Paracetamol

evidence_span

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experimental_model

Cerebrospinal fluid and blood sampled from 26 adult male patients after intravenous paracetamol

exposure

1 gram intravenous paracetamol, with AM404 measured by liquid chromatography-tandem mass spectrometry

limitations

The first human demonstration that the metabolite reaches the central nervous system, and simultaneously the strongest quantitative objection to its importance, since the concentrations found are far below the reported potency of the compound.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

The metabolite really is in human brain fluid, at about a thousandth of the concentration it is thought to need.

primary_references

[apap-p29238213] First evidence of the conversion of paracetamol to AM404 in human cerebrospinal fluid. (2017). https://pubmed.ncbi.nlm.nih.gov/29238213/ DOI: 10.2147/jpr.s143500

tissue_or_cell_type

Cerebrospinal fluid

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 363–374

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cerebrospinal fluid and blood sampled from 26 adult male patients after intravenous paracetamol · source_derived_draft · unverified_draft

### apap-am404-in-human-csf-but-low Cerebrospinal fluid and blood were collected from 26 adult male patients between 10 and 211 minutes after intravenous administration of 1 gram of paracetamol, AM404 was detected in 17 of the 26 evaluable cerebrospinal fluid samples at 5 to 40 nanomoles per litre and paracetamol was measurable within 10 minutes with a maximum measured concentration of 60 micromoles per litre at 206 minutes, the first report of AM404 in human cerebrospinal fluid after paracetamol, although the measured concentrations were far below the previously documented half-maximal inhibitory concentration for this metabolite. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The metabolite really is in human brain fluid, at about a thousandth of the concentration it is thought to need. organism: Human tissue_or_cell_type: Cerebrospinal fluid experimental_model: Cerebrospinal fluid and blood sampled from 26 adult male patients after intravenous paracetamol limitations: The first human demonstration that the metabolite reaches the central nervous system, and simultaneously the strongest quantitative objection to its importance, since the concentrations found are far below the reported potency of the compound. exposure: 1 gram intravenous paracetamol, with AM404 measured by liquid chromatography-tandem mass spectrometry evidence_span: {"source_cache": "artifacts/paracetamol-research/29238213.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3f8c752d7c1931585f2ce5bc6059b45b103e73fbc7e067912b0d2c60e8541165", "start_char": 0, "end_char": 1557, "text_sha256": "3f8c752d7c1931585f2ce5bc6059b45b103e73fbc7e067912b0d2c60e8541165"} [apap-p29238213] First evidence of the conversion of paracetamol to AM404 in human cerebrospinal fluid. (2017). https://pubmed.ncbi.nlm.nih.gov/29238213/ DOI: 10.2147/jpr.s143500

evidence_span

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experimental_model

Cisternal cerebrospinal fluid sampled from unanaesthetised cats during fever and after antipyretics

exposure

Shigella dysenteriae pyrogen given into the third ventricle, cisterna magna or intravenously, with indomethacin, paracetamol and aspirin

limitations

Bioassay on a stomach strip rather than direct measurement, and prostaglandin E-like activity rather than identified prostaglandin E2. It is the record that connects fever to central prostaglandin and to this drug.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Cat

plain_language

Fever raises a prostaglandin in the fluid round the brain, and this drug brings both down together.

primary_references

[apap-p4588122] Effect of pyrogen and antipyretics on prostaglandin acitvity in cisternal c.s.f. of unanaesthetized cats. (1973). https://pubmed.ncbi.nlm.nih.gov/4588122/ DOI: 10.1113/jphysiol.1973.sp010346

tissue_or_cell_type

Cerebrospinal fluid and hypothalamus

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 285–296

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cisternal cerebrospinal fluid sampled from unanaesthetised cats during fever and after antipyretics · source_derived_draft · unverified_draft

### apap-antipyresis-follows-central-prostaglandin Prostaglandin E-like activity in cisternal cerebrospinal fluid was usually undetectable or low at normal body temperature and increased, often many-fold, during pyrogen fever irrespective of the route of pyrogen administration, and the antipyretic drugs indomethacin, paracetamol and aspirin injected intraperitoneally during the fever brought down temperature and returned the activity to low levels, with chromatography placing the activity in the zone of the E series prostaglandins, supporting the theory that pyrogens produce fever by increasing prostaglandin synthesis in the preoptic anterior hypothalamic area and that antipyretics of the aspirin type act by inhibiting that synthesis. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Fever raises a prostaglandin in the fluid round the brain, and this drug brings both down together. organism: Cat tissue_or_cell_type: Cerebrospinal fluid and hypothalamus experimental_model: Cisternal cerebrospinal fluid sampled from unanaesthetised cats during fever and after antipyretics limitations: Bioassay on a stomach strip rather than direct measurement, and prostaglandin E-like activity rather than identified prostaglandin E2. It is the record that connects fever to central prostaglandin and to this drug. exposure: Shigella dysenteriae pyrogen given into the third ventricle, cisterna magna or intravenously, with indomethacin, paracetamol and aspirin evidence_span: {"source_cache": "artifacts/paracetamol-research/4588122.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "274f00794352ea4d44e1ef2c2cf46a094d9a03752d7c485a2d6222e519534aa9", "start_char": 0, "end_char": 2254, "text_sha256": "274f00794352ea4d44e1ef2c2cf46a094d9a03752d7c485a2d6222e519534aa9"} [apap-p4588122] Effect of pyrogen and antipyretics on prostaglandin acitvity in cisternal c.s.f. of unanaesthetized cats. (1973). https://pubmed.ncbi.nlm.nih.gov/4588122/ DOI: 10.1113/jphysiol.1973.sp010346

evidence_span

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experimental_model

Tissue glutathione and covalent binding of tritiated metabolites in CD-1 mice and Sprague-Dawley rats

exposure

Intraperitoneal acetaminophen, with and without prior 3-methylcholanthrene induction

limitations

Compares two organs and two species in the same design. The authors note the covalent binding measurement is extremely sensitive to trace radiochemical impurity, which is an honest caution about the method.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Mouse and rat

plain_language

The drug empties the cell of its protective thiol and then sticks to proteins, most of all in mouse liver.

primary_references

[apap-p660552] Covalent binding of metabolites of acetaminophen to kidney protein and depletion of renal glutathione. (1978). https://pubmed.ncbi.nlm.nih.gov/660552/ DOI: 10.1016/s0022-3565(25)31316-9

tissue_or_cell_type

Liver, kidney cortex and renal papilla

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 402–413

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Tissue glutathione and covalent binding of tritiated metabolites in CD-1 mice and Sprague-Dawley rats · source_derived_draft · unverified_draft

### apap-binding-tracks-glutathione-loss After intraperitoneal acetaminophen, tissue glutathione was reduced more in mice than in rats and more in liver than in kidney without appearance of oxidized glutathione in either tissue, covalent binding of tritiated metabolites to tissue protein was likewise greater in mice than rats and greater in liver than kidney, prior 3-methylcholanthrene produced far greater induced changes in liver than kidney suggesting the reactive metabolite forms by slightly different mechanisms in each organ, and at doses below those causing demonstrable acute toxicity the duration of covalent binding was longer for renal papilla than for renal cortex or liver. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The drug empties the cell of its protective thiol and then sticks to proteins, most of all in mouse liver. organism: Mouse and rat tissue_or_cell_type: Liver, kidney cortex and renal papilla experimental_model: Tissue glutathione and covalent binding of tritiated metabolites in CD-1 mice and Sprague-Dawley rats limitations: Compares two organs and two species in the same design. The authors note the covalent binding measurement is extremely sensitive to trace radiochemical impurity, which is an honest caution about the method. exposure: Intraperitoneal acetaminophen, with and without prior 3-methylcholanthrene induction evidence_span: {"source_cache": "artifacts/paracetamol-research/660552.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7041ada7ee2ce923645d1103db3a3dccc3febcf138c5095e24aa96cdbc04e9e3", "start_char": 0, "end_char": 1309, "text_sha256": "7041ada7ee2ce923645d1103db3a3dccc3febcf138c5095e24aa96cdbc04e9e3"} [apap-p660552] Covalent binding of metabolites of acetaminophen to kidney protein and depletion of renal glutathione. (1978). https://pubmed.ncbi.nlm.nih.gov/660552/ DOI: 10.1016/s0022-3565(25)31316-9

evidence_span

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experimental_model

Cloning and expression of cyclooxygenase-1-derived transcripts from canine cerebral cortex in insect cells

exposure

Canine COX-3 compared with murine cyclooxygenase-1 and -2 against acetaminophen, phenacetin, antipyrine and dipyrone

limitations

The paper that proposed the answer. Its activity data are for the canine protein expressed in insect cells; the human claim is about messenger RNA abundance, not about an active protein.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Dog and human

plain_language

A third form of the enzyme was reported in dog brain, and it was the one this drug blocked.

primary_references

[apap-p12242329] COX-3, a cyclooxygenase-1 variant inhibited by acetaminophen and other analgesic/antipyretic drugs: cloning, structure, and expression. (2002). https://pubmed.ncbi.nlm.nih.gov/12242329/ DOI: 10.1073/pnas.162468699

tissue_or_cell_type

Cerebral cortex

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 194–205

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cloning and expression of cyclooxygenase-1-derived transcripts from canine cerebral cortex in insect cells · source_derived_draft · unverified_draft

### apap-cox3-proposed A third distinct cyclooxygenase isozyme, COX-3, made from the cyclooxygenase-1 gene but retaining intron 1 in its messenger RNA, was described as expressed in canine cerebral cortex and as an approximately 5.2 kilobase transcript most abundant in human cerebral cortex and heart, the retained intron introducing an insertion of 30 to 34 amino acids into the hydrophobic signal peptide; canine COX-3 expressed in insect cells possessed glycosylation-dependent cyclooxygenase activity and was selectively inhibited by analgesic and antipyretic drugs such as acetaminophen, phenacetin, antipyrine and dipyrone, so that inhibition of COX-3 could represent a primary central mechanism by which these drugs decrease pain and possibly fever. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: A third form of the enzyme was reported in dog brain, and it was the one this drug blocked. organism: Dog and human tissue_or_cell_type: Cerebral cortex experimental_model: Cloning and expression of cyclooxygenase-1-derived transcripts from canine cerebral cortex in insect cells limitations: The paper that proposed the answer. Its activity data are for the canine protein expressed in insect cells; the human claim is about messenger RNA abundance, not about an active protein. exposure: Canine COX-3 compared with murine cyclooxygenase-1 and -2 against acetaminophen, phenacetin, antipyrine and dipyrone evidence_span: {"source_cache": "artifacts/paracetamol-research/12242329.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0c00962f9e58da9af386335ac3312d5c260d637270d80481a6f55d0ebec67a78", "start_char": 0, "end_char": 1711, "text_sha256": "0c00962f9e58da9af386335ac3312d5c260d637270d80481a6f55d0ebec67a78"} [apap-p12242329] COX-3, a cyclooxygenase-1 variant inhibited by acetaminophen and other analgesic/antipyretic drugs: cloning, structure, and expression. (2002). https://pubmed.ncbi.nlm.nih.gov/12242329/ DOI: 10.1073/pnas.162468699

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

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experimental_model

Double-blind placebo-controlled oral challenge and desensitisation in three aspirin-sensitive asthmatic subjects

exposure

1000 to 2000 milligram acetaminophen challenges, with aspirin desensitisation and acetaminophen desensitisation

limitations

Three subjects, selected for a history of reacting, so the frequency of cross-reactivity cannot be read from it. The cross-desensitisation result is what identifies the shared mechanism.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

Desensitise the patient to aspirin and they stop reacting to paracetamol, so it is the same mechanism at work.

primary_references

[apap-p2666482] Cross sensitivity with acetaminophen in aspirin-sensitive subjects with asthma. (1989). https://pubmed.ncbi.nlm.nih.gov/2666482/ DOI: 10.1016/0091-6749(89)90174-7

tissue_or_cell_type

Airway

trigger_kind

biomarker_context Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 454–465

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind placebo-controlled oral challenge and desensitisation in three aspirin-sensitive asthmatic subjects · source_derived_draft · unverified_draft

### apap-cross-desensitisation-shows-shared-mechanism Three aspirin-sensitive asthmatic subjects with a history of reactions underwent double-blind placebo-controlled challenges and reacted to 1000 milligrams of acetaminophen with a greater than 20% fall in forced expiratory volume in one second, two were desensitized to aspirin and then rechallenged with 1000 milligrams of acetaminophen without reaction, and two were desensitized to acetaminophen achieving refractoriness to 1500 but not 2000 milligrams, so cross sensitivity was documented at large challenge doses and the cross desensitization suggests similar mechanisms are responsible for reactions to aspirin, non-steroidal anti-inflammatory drugs and acetaminophen. Condition category: biomarker_context nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Desensitise the patient to aspirin and they stop reacting to paracetamol, so it is the same mechanism at work. organism: Human tissue_or_cell_type: Airway experimental_model: Double-blind placebo-controlled oral challenge and desensitisation in three aspirin-sensitive asthmatic subjects limitations: Three subjects, selected for a history of reacting, so the frequency of cross-reactivity cannot be read from it. The cross-desensitisation result is what identifies the shared mechanism. exposure: 1000 to 2000 milligram acetaminophen challenges, with aspirin desensitisation and acetaminophen desensitisation evidence_span: {"source_cache": "artifacts/paracetamol-research/2666482.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9c731e77d65955b683aa03e7df1252729e11b1fb8bed714b9138f22c725eac2b", "start_char": 0, "end_char": 1081, "text_sha256": "9c731e77d65955b683aa03e7df1252729e11b1fb8bed714b9138f22c725eac2b"} [apap-p2666482] Cross sensitivity with acetaminophen in aspirin-sensitive subjects with asthma. (1989). https://pubmed.ncbi.nlm.nih.gov/2666482/ DOI: 10.1016/0091-6749(89)90174-7

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_span

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experimental_model

Brain and spinal cord metabolite identification in wild-type and fatty acid amide hydrolase knockout mice

exposure

Acetaminophen, with the conjugation step tested by genetic deletion of the conjugating enzyme

limitations

Identifies a previously unknown route of drug metabolism and proves the enzyme by knockout. The downstream activities are measured on purified enzyme and cell lines rather than in the treated animal.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Mouse

plain_language

The brain takes the drug apart and builds the pieces into something new, and that something is what acts.

primary_references

[apap-p15987694] Conversion of acetaminophen to the bioactive N-acylphenolamine AM404 via fatty acid amide hydrolase-dependent arachidonic acid conjugation in the nervous system. (2005). https://pubmed.ncbi.nlm.nih.gov/15987694/ DOI: 10.1074/jbc.m501489200

tissue_or_cell_type

Brain and spinal cord

trigger_kind

machinery_impairment Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 298–309

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Brain and spinal cord metabolite identification in wild-type and fatty acid amide hydrolase knockout mice · source_derived_draft · unverified_draft

### apap-faah-builds-am404 Acetaminophen, following deacetylation to its primary amine, is conjugated with arachidonic acid in the brain and the spinal cord to form the potent TRPV1 agonist N-arachidonoylphenolamine, and this conjugation is absent in mice lacking the enzyme fatty acid amide hydrolase; AM404 also inhibits purified cyclooxygenase-1 and -2 and prostaglandin synthesis in lipopolysaccharide-stimulated macrophages and acts on the endogenous cannabinoid system, identifying fatty acid conjugation as a novel pathway for drug metabolism. Condition category: machinery_impairment nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The brain takes the drug apart and builds the pieces into something new, and that something is what acts. organism: Mouse tissue_or_cell_type: Brain and spinal cord experimental_model: Brain and spinal cord metabolite identification in wild-type and fatty acid amide hydrolase knockout mice limitations: Identifies a previously unknown route of drug metabolism and proves the enzyme by knockout. The downstream activities are measured on purified enzyme and cell lines rather than in the treated animal. exposure: Acetaminophen, with the conjugation step tested by genetic deletion of the conjugating enzyme evidence_span: {"source_cache": "artifacts/paracetamol-research/15987694.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8da7599ee6674ced34346ae03fae0e421bcc5c1f53b0cb879145d7a511502001", "start_char": 0, "end_char": 1093, "text_sha256": "8da7599ee6674ced34346ae03fae0e421bcc5c1f53b0cb879145d7a511502001"} [apap-p15987694] Conversion of acetaminophen to the bioactive N-acylphenolamine AM404 via fatty acid amide hydrolase-dependent arachidonic acid conjugation in the nervous system. (2005). https://pubmed.ncbi.nlm.nih.gov/15987694/ DOI: 10.1074/jbc.m501489200

evidence_span

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experimental_model

Ex vivo and in vitro human whole blood cyclooxygenase assays in five volunteers given a single oral dose

exposure

1000 milligrams oral acetaminophen, with coagulation-induced thromboxane B2 and lipopolysaccharide-induced prostaglandin E2 as isoform indices

limitations

Measures both isoform indices in dosed people and relates them to plasma concentration. Five volunteers and a single dose.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

In people it blocks the second enzyme as hard as a proper anti-inflammatory does, and never blocks the first enough to touch platelets.

primary_references

[apap-p17884974] Acetaminophen (paracetamol) is a selective cyclooxygenase-2 inhibitor in man. (2008). https://pubmed.ncbi.nlm.nih.gov/17884974/ DOI: 10.1096/fj.07-8506com

tissue_or_cell_type

Whole blood

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 259–270

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Ex vivo and in vitro human whole blood cyclooxygenase assays in five volunteers given a single oral dose · source_derived_draft · unverified_draft

### apap-four-fold-cox2-selective-in-man In vitro acetaminophen elicited a 4.4-fold selectivity toward cyclooxygenase-2 inhibition with half-maximal inhibitory concentrations of 113.7 micromolar for cyclooxygenase-1 and 25.8 micromolar for cyclooxygenase-2, following a single oral 1000 milligram dose maximal ex vivo inhibitions were 56% for cyclooxygenase-1 and 83% for cyclooxygenase-2, plasma concentrations remained above the in vitro cyclooxygenase-2 value for at least 5 hours, and ex vivo values compared favourably with in vitro ones; acetaminophen inhibited cyclooxygenase-2 by more than 80%, comparable to non-steroidal anti-inflammatory drugs and selective inhibitors, but the greater than 95% cyclooxygenase-1 blockade relevant for suppression of platelet function was not achieved, and in view of its substantial cyclooxygenase-2 inhibition the cardiovascular warnings defined for selective inhibitors should also be considered. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: In people it blocks the second enzyme as hard as a proper anti-inflammatory does, and never blocks the first enough to touch platelets. organism: Human tissue_or_cell_type: Whole blood experimental_model: Ex vivo and in vitro human whole blood cyclooxygenase assays in five volunteers given a single oral dose limitations: Measures both isoform indices in dosed people and relates them to plasma concentration. Five volunteers and a single dose. exposure: 1000 milligrams oral acetaminophen, with coagulation-induced thromboxane B2 and lipopolysaccharide-induced prostaglandin E2 as isoform indices evidence_span: {"source_cache": "artifacts/paracetamol-research/17884974.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e2856e9fc1c319219fd3d3cb145f70bb1157f7ca0baa0221594c9583cf7ddc23", "start_char": 0, "end_char": 1857, "text_sha256": "e2856e9fc1c319219fd3d3cb145f70bb1157f7ca0baa0221594c9583cf7ddc23"} [apap-p17884974] Acetaminophen (paracetamol) is a selective cyclooxygenase-2 inhibitor in man. (2008). https://pubmed.ncbi.nlm.nih.gov/17884974/ DOI: 10.1096/fj.07-8506com

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

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experimental_model

Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition

exposure

Acetaminophen with 2 micromolar arachidonic acid, and with prostaglandin G2, 12-hydroperoxyeicosatetraenoic acid or tert-butyl hydroperoxide added back

limitations

The decisive record of the chapter: it measures a 435-fold difference between two human cell types, shows it is not isoform selectivity, and reverses it by adding the peroxide back.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

The same drug is four hundred times weaker in a platelet than in an inflamed blood vessel, and it is not because the enzymes differ.

primary_references

[apap-p12011469] Determinants of the cellular specificity of acetaminophen as an inhibitor of prostaglandin H(2) synthases. (2002). https://pubmed.ncbi.nlm.nih.gov/12011469/ DOI: 10.1073/pnas.102588199

tissue_or_cell_type

Endothelium and platelets

trigger_kind

biomarker_context Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 90–101

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition · source_derived_draft · unverified_draft

### apap-four-hundred-fold-cell-difference Acetaminophen inhibited prostaglandin H synthase activity with a half-maximal inhibitory concentration of 4.3 micromolar in interleukin-1-alpha-stimulated human umbilical vein endothelial cells against 1,870 micromolar in the platelet with 2 micromolar arachidonic acid as substrate, and this difference is not caused by isoform selectivity because acetaminophen inhibits purified ovine prostaglandin H synthase-1 and murine recombinant synthase-2 equally. Condition category: biomarker_context nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The same drug is four hundred times weaker in a platelet than in an inflamed blood vessel, and it is not because the enzymes differ. organism: Human tissue_or_cell_type: Endothelium and platelets experimental_model: Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition limitations: The decisive record of the chapter: it measures a 435-fold difference between two human cell types, shows it is not isoform selectivity, and reverses it by adding the peroxide back. exposure: Acetaminophen with 2 micromolar arachidonic acid, and with prostaglandin G2, 12-hydroperoxyeicosatetraenoic acid or tert-butyl hydroperoxide added back evidence_span: {"source_cache": "artifacts/paracetamol-research/12011469.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d", "start_char": 0, "end_char": 1561, "text_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d"} [apap-p12011469] Determinants of the cellular specificity of acetaminophen as an inhibitor of prostaglandin H(2) synthases. (2002). https://pubmed.ncbi.nlm.nih.gov/12011469/ DOI: 10.1073/pnas.102588199

evidence_span

{"source_cache": "artifacts/paracetamol-research/2511429.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8dbe8c6f23fc857be6bba07e2a518c59f8dc76c9f8625c25ba84030c43f6e636", "start_char": 0, "end_char": 1593, "text_sha256": "8dbe8c6f23fc857be6bba07e2a518c59f8dc76c9f8625c25ba84030c43f6e636"}

experimental_model

Prostaglandin H synthase apoenzyme reconstituted with manganese or iron protoporphyrin

exposure

Eugenol, guaiacol, butylated hydroxyanisole and acetaminophen against both reconstituted forms, with prostaglandin G2 added

limitations

The manganese-reconstituted enzyme retains cyclooxygenase but little peroxidase activity, which is what lets this study separate the two proposed sites. Its conclusion is the opposite of the peroxide-tone account.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Enzyme

plain_language

In an enzyme stripped of its peroxidase the drug still works, which argues it also competes at the other site.

primary_references

[apap-p2511429] Mechanism of inhibition of prostaglandin H synthase by eugenol and other phenolic peroxidase substrates. (1989). https://pubmed.ncbi.nlm.nih.gov/2511429/ DOI: 10.1016/s0026-895x(25)09658-0

tissue_or_cell_type

Reconstituted prostaglandin H synthase

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 155–166

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prostaglandin H synthase apoenzyme reconstituted with manganese or iron protoporphyrin · source_derived_draft · unverified_draft

### apap-maybe-the-cox-site-instead Higher concentrations of eugenol were required to inhibit iron-reconstituted prostaglandin H synthase than the manganese-reconstituted enzyme which retains cyclooxygenase but not peroxidase activity, inhibition was highly dependent on arachidonic acid concentration, adding 10 micromolar prostaglandin G2 did not prevent the inhibitory effects, and other phenolic compounds including guaiacol, butylated hydroxyanisole and acetaminophen inhibited the manganese enzyme similarly, demonstrating that these compounds specifically inhibit the cyclooxygenase component in addition to or independent of their effect on peroxide tone, which the authors suggest is due to competition with arachidonic acid for the active site. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: In an enzyme stripped of its peroxidase the drug still works, which argues it also competes at the other site. organism: Enzyme tissue_or_cell_type: Reconstituted prostaglandin H synthase experimental_model: Prostaglandin H synthase apoenzyme reconstituted with manganese or iron protoporphyrin limitations: The manganese-reconstituted enzyme retains cyclooxygenase but little peroxidase activity, which is what lets this study separate the two proposed sites. Its conclusion is the opposite of the peroxide-tone account. exposure: Eugenol, guaiacol, butylated hydroxyanisole and acetaminophen against both reconstituted forms, with prostaglandin G2 added evidence_span: {"source_cache": "artifacts/paracetamol-research/2511429.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8dbe8c6f23fc857be6bba07e2a518c59f8dc76c9f8625c25ba84030c43f6e636", "start_char": 0, "end_char": 1593, "text_sha256": "8dbe8c6f23fc857be6bba07e2a518c59f8dc76c9f8625c25ba84030c43f6e636"} [apap-p2511429] Mechanism of inhibition of prostaglandin H synthase by eugenol and other phenolic peroxidase substrates. (1989). https://pubmed.ncbi.nlm.nih.gov/2511429/ DOI: 10.1016/s0026-895x(25)09658-0

evidence_span

{"source_cache": "artifacts/paracetamol-research/12598417.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e5796a25a03c77d12e8376a60aa094e481bd0c2ab58b29ddcb70027ab477b267", "start_char": 0, "end_char": 1894, "text_sha256": "e5796a25a03c77d12e8376a60aa094e481bd0c2ab58b29ddcb70027ab477b267"}

experimental_model

Human whole blood and isolated monocytes and platelets with parallel prostaglandin E2 and thromboxane B2 measurement

exposure

Acetaminophen at therapeutic plasma concentrations of 100 and 300 micromolar, in whole blood and in isolated cells

limitations

The whole blood against isolated cell comparison shows plasma components matter, and measuring two prostanoids in parallel separates the synthase from the downstream synthase. Ex vivo only.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

In whole blood it nearly abolishes the inflammatory prostaglandin; in isolated cells it manages only sixty per cent.

primary_references

[apap-p12598417] Effects of acetaminophen on constitutive and inducible prostanoid biosynthesis in human blood cells. (2003). https://pubmed.ncbi.nlm.nih.gov/12598417/ DOI: 10.1038/sj.bjp.0705078

tissue_or_cell_type

Monocytes and platelets

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 272–283

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human whole blood and isolated monocytes and platelets with parallel prostaglandin E2 and thromboxane B2 measurement · source_derived_draft · unverified_draft

### apap-plasma-changes-the-answer Acetaminophen inhibited lipopolysaccharide-induced whole blood prostaglandin E2 and thromboxane B2 production with half-maximal inhibitory concentrations of 44 and 94 micromolar, at therapeutic concentrations of 100 and 300 micromolar it reduced prostaglandin E2 more than thromboxane B2, but in isolated monocytes both were maximally reduced by only 60%, and at the same concentrations it caused a similar and incomplete inhibition of platelet prostaglandin E2 and thromboxane B2 during whole blood clotting, so that in the presence of plasma the drug almost completely suppressed inducible prostaglandin E2 biosynthesis through effects on both cyclooxygenase-2 and inducible prostaglandin E synthase. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: In whole blood it nearly abolishes the inflammatory prostaglandin; in isolated cells it manages only sixty per cent. organism: Human tissue_or_cell_type: Monocytes and platelets experimental_model: Human whole blood and isolated monocytes and platelets with parallel prostaglandin E2 and thromboxane B2 measurement limitations: The whole blood against isolated cell comparison shows plasma components matter, and measuring two prostanoids in parallel separates the synthase from the downstream synthase. Ex vivo only. exposure: Acetaminophen at therapeutic plasma concentrations of 100 and 300 micromolar, in whole blood and in isolated cells evidence_span: {"source_cache": "artifacts/paracetamol-research/12598417.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e5796a25a03c77d12e8376a60aa094e481bd0c2ab58b29ddcb70027ab477b267", "start_char": 0, "end_char": 1894, "text_sha256": "e5796a25a03c77d12e8376a60aa094e481bd0c2ab58b29ddcb70027ab477b267"} [apap-p12598417] Effects of acetaminophen on constitutive and inducible prostanoid biosynthesis in human blood cells. (2003). https://pubmed.ncbi.nlm.nih.gov/12598417/ DOI: 10.1038/sj.bjp.0705078

evidence_span

{"source_cache": "artifacts/paracetamol-research/11370851.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4eeda4b163828f2cc2a4341c4810df6bf6c683d6165eeb09479104f185e52ca4", "start_char": 0, "end_char": 1086, "text_sha256": "4eeda4b163828f2cc2a4341c4810df6bf6c683d6165eeb09479104f185e52ca4"}

experimental_model

Purified ovine cyclooxygenase-1 and human cyclooxygenase-2 assayed with and without a peroxide-removing system

exposure

Acetaminophen with and without glutathione peroxidase and glutathione

limitations

Adding a peroxide-removing system is the manipulation that reveals the mechanism, because it changes potency thirtyfold without changing the drug. Purified enzyme, so the concentrations are not tissue concentrations.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Sheep and human enzyme

plain_language

Take the peroxide away and the same drug becomes thirty times stronger, which is the whole mechanism in one experiment.

primary_references

[apap-p11370851] Mechanism of acetaminophen inhibition of cyclooxygenase isoforms. (2001). https://pubmed.ncbi.nlm.nih.gov/11370851/ DOI: 10.1006/abbi.2000.2232

tissue_or_cell_type

Purified cyclooxygenase

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 77–88

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified ovine cyclooxygenase-1 and human cyclooxygenase-2 assayed with and without a peroxide-removing system · source_derived_draft · unverified_draft

### apap-potency-depends-on-peroxide The potency of acetaminophen against both purified ovine cyclooxygenase-1 and human cyclooxygenase-2 was increased approximately 30-fold by the presence of glutathione peroxidase and glutathione, giving half-maximal inhibitory concentrations of 33 and 980 micromolar respectively, acetaminophen was found to be a good reducing agent of both enzymes, and the results are consistent with a mechanism in which it reduces the active oxidized form of the enzyme to the resting form, so that inhibition would be more effective under conditions of low peroxide concentration, consistent with the known tissue selectivity. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Take the peroxide away and the same drug becomes thirty times stronger, which is the whole mechanism in one experiment. organism: Sheep and human enzyme tissue_or_cell_type: Purified cyclooxygenase experimental_model: Purified ovine cyclooxygenase-1 and human cyclooxygenase-2 assayed with and without a peroxide-removing system limitations: Adding a peroxide-removing system is the manipulation that reveals the mechanism, because it changes potency thirtyfold without changing the drug. Purified enzyme, so the concentrations are not tissue concentrations. exposure: Acetaminophen with and without glutathione peroxidase and glutathione evidence_span: {"source_cache": "artifacts/paracetamol-research/11370851.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4eeda4b163828f2cc2a4341c4810df6bf6c683d6165eeb09479104f185e52ca4", "start_char": 0, "end_char": 1086, "text_sha256": "4eeda4b163828f2cc2a4341c4810df6bf6c683d6165eeb09479104f185e52ca4"} [apap-p11370851] Mechanism of acetaminophen inhibition of cyclooxygenase isoforms. (2001). https://pubmed.ncbi.nlm.nih.gov/11370851/ DOI: 10.1006/abbi.2000.2232

evidence_span

{"source_cache": "artifacts/paracetamol-research/7506185.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b38b08631ecb8137b8297b631b8dab0a4378d5445e29c557e3586b546e0e874f", "start_char": 0, "end_char": 1590, "text_sha256": "b38b08631ecb8137b8297b631b8dab0a4378d5445e29c557e3586b546e0e874f"}

experimental_model

Oral challenge series in 112 and then 284 patients intolerant of non-steroidal anti-inflammatory drugs

exposure

Challenges with aspirin, dipyrone, paracetamol, imidazole-hydroxybenzoate and nimesulide

limitations

Provides the denominator that the case reports lack, and records two anaphylactic shocks during challenge, which is why the authors restrict the procedure.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

About one in twelve challenges with paracetamol was positive in people already intolerant of these drugs.

primary_references

[apap-p7506185] Oral challenge with alternative nonsteroidal antiinflammatory drugs (NSAIDs) and paracetamol in patients intolerant to these agents. (1993). https://pubmed.ncbi.nlm.nih.gov/7506185/ DOI: 10.2165/00003495-199300461-00065

tissue_or_cell_type

Whole body

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 480–491

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Oral challenge series in 112 and then 284 patients intolerant of non-steroidal anti-inflammatory drugs · source_derived_draft · unverified_draft

### apap-seven-in-eighty-three Of 237 challenges with various non-steroidal anti-inflammatory drugs and paracetamol in 101 intolerant patients, 19 challenges were positive and 2 patients developed anaphylactic shock, with a ratio of positive to total challenges of 7 of 83 for paracetamol, 2 of 49 for imidazole-hydroxybenzoate and 0 of 30 for nimesulide, and the authors conclude that a positive history of intolerance to a given drug is sufficient reason to contraindicate its use even for diagnostic challenge, which should be restricted to assessing tolerability of alternatives. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: About one in twelve challenges with paracetamol was positive in people already intolerant of these drugs. organism: Human tissue_or_cell_type: Whole body experimental_model: Oral challenge series in 112 and then 284 patients intolerant of non-steroidal anti-inflammatory drugs limitations: Provides the denominator that the case reports lack, and records two anaphylactic shocks during challenge, which is why the authors restrict the procedure. exposure: Challenges with aspirin, dipyrone, paracetamol, imidazole-hydroxybenzoate and nimesulide evidence_span: {"source_cache": "artifacts/paracetamol-research/7506185.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b38b08631ecb8137b8297b631b8dab0a4378d5445e29c557e3586b546e0e874f", "start_char": 0, "end_char": 1590, "text_sha256": "b38b08631ecb8137b8297b631b8dab0a4378d5445e29c557e3586b546e0e874f"} [apap-p7506185] Oral challenge with alternative nonsteroidal antiinflammatory drugs (NSAIDs) and paracetamol in patients intolerant to these agents. (1993). https://pubmed.ncbi.nlm.nih.gov/7506185/ DOI: 10.2165/00003495-199300461-00065

evidence_span

{"source_cache": "artifacts/paracetamol-research/3124965.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502", "start_char": 0, "end_char": 2236, "text_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502"}

experimental_model

Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation

exposure

Acetaminophen from 20 micromolar to above 10 millimolar, with glutathione, ascorbate and indomethacin

limitations

Shows that the drug both stimulates and inhibits the same enzyme depending on concentration, and that the enzyme makes NAPQI from it. A microsomal preparation at concentrations far above therapeutic.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Sheep

plain_language

At low concentrations the drug feeds the enzyme and at high concentrations it stalls it, both by handing over electrons.

primary_references

[apap-p3124965] Acetaminophen and analogs as cosubstrates and inhibitors of prostaglandin H synthase. (1988). https://pubmed.ncbi.nlm.nih.gov/3124965/ DOI: 10.1016/0009-2797(88)90101-9

tissue_or_cell_type

Seminal vesicle microsomes

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 116–127

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation · source_derived_draft · unverified_draft

### apap-stimulates-then-inhibits Relatively low concentrations of acetaminophen from 20 to 200 micromolar stimulate prostaglandin H synthase activity in ram seminal vesicle microsomes whereas concentrations above 10 millimolar inhibit the conversion of arachidonic acid to prostaglandin G2, both activities apparently involving reduction of oxidized complexes of the enzyme and roughly correlating with the electrochemical half-wave oxidation potentials of a series of hydroxyacetanilides, consistent with common intermediate enzyme forms for both cyclooxygenase and hydroperoxidase catalysed reactions of which one is reduced at low drug concentrations to stimulate and another at higher concentrations to inhibit. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: At low concentrations the drug feeds the enzyme and at high concentrations it stalls it, both by handing over electrons. organism: Sheep tissue_or_cell_type: Seminal vesicle microsomes experimental_model: Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation limitations: Shows that the drug both stimulates and inhibits the same enzyme depending on concentration, and that the enzyme makes NAPQI from it. A microsomal preparation at concentrations far above therapeutic. exposure: Acetaminophen from 20 micromolar to above 10 millimolar, with glutathione, ascorbate and indomethacin evidence_span: {"source_cache": "artifacts/paracetamol-research/3124965.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502", "start_char": 0, "end_char": 2236, "text_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502"} [apap-p3124965] Acetaminophen and analogs as cosubstrates and inhibitors of prostaglandin H synthase. (1988). https://pubmed.ncbi.nlm.nih.gov/3124965/ DOI: 10.1016/0009-2797(88)90101-9

evidence_span

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experimental_model

Human HepG2 cells and mice given acute and repeated doses, with PPAR-alpha-deficient animals and a human case

exposure

0.5 to 20 millimolar in cells and 750 milligrams per kilogram in mice, acute and repeated over four days

limitations

Follows a lipid signalling system across cells, mice, knockouts and one human case. The biphasic time course is the informative part and complicates any single-timepoint reading.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human cells, mouse and human

plain_language

The same lipid system that makes the painkilling metabolite is knocked down by an overdose and then rebounds, and animals lacking it fare worse.

primary_references

[apap-p29056914] Acetaminophen-Induced Liver Injury Alters the Acyl Ethanolamine-Based Anti-Inflammatory Signaling System in Liver. (2017). https://pubmed.ncbi.nlm.nih.gov/29056914/ DOI: 10.3389/fphar.2017.00705

tissue_or_cell_type

Liver

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 441–452

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human HepG2 cells and mice given acute and repeated doses, with PPAR-alpha-deficient animals and a human case · source_derived_draft · unverified_draft

### apap-the-lipid-brake-fails-then-rebounds Acetaminophen produced a biphasic response in the N-acyl ethanolamide and PPAR alpha system, with decreased PPAR alpha expression after 6 hours followed by a generalised increase of system components including PPAR alpha, NAPE-PLD and fatty acid amide hydrolase and of the N-acyl ethanolamides after 24 hours, confirmed in mice where gene expression of PPAR alpha and fatty acid amide hydrolase fell at 6 hours and rose by 24 hours, repeated administration decreased both and increased liver N-acyl ethanolamides with complete restoration after 15 days of rest, immunohistochemistry in a human case of acetaminophen hepatotoxicity confirmed the decrements, and damage-related alterations after repeated administration were aggravated in PPAR alpha-deficient mice. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The same lipid system that makes the painkilling metabolite is knocked down by an overdose and then rebounds, and animals lacking it fare worse. organism: Human cells, mouse and human tissue_or_cell_type: Liver experimental_model: Human HepG2 cells and mice given acute and repeated doses, with PPAR-alpha-deficient animals and a human case limitations: Follows a lipid signalling system across cells, mice, knockouts and one human case. The biphasic time course is the informative part and complicates any single-timepoint reading. exposure: 0.5 to 20 millimolar in cells and 750 milligrams per kilogram in mice, acute and repeated over four days evidence_span: {"source_cache": "artifacts/paracetamol-research/29056914.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2ca7517052bab3c774f315af85f3aa8cdf810e43dc44444724bff46e2f1bdab3", "start_char": 0, "end_char": 2081, "text_sha256": "2ca7517052bab3c774f315af85f3aa8cdf810e43dc44444724bff46e2f1bdab3"} [apap-p29056914] Acetaminophen-Induced Liver Injury Alters the Acyl Ethanolamine-Based Anti-Inflammatory Signaling System in Liver. (2017). https://pubmed.ncbi.nlm.nih.gov/29056914/ DOI: 10.3389/fphar.2017.00705

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/paracetamol-research/36191122.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "859db1958aeb26b75a34a32e4dd1c4713dc7db413717cefe62a3659856db7568", "start_char": 0, "end_char": 3325, "text_sha256": "859db1958aeb26b75a34a32e4dd1c4713dc7db413717cefe62a3659856db7568"}

experimental_model

Review of point-of-care testing and antidote guidance for acute overdose

exposure

Serum acetaminophen concentration interpreted against the Rumack-Matthew nomogram

limitations

A health-technology review rather than primary research. The nomogram figures it quotes are derived from patients not treated with antidote, which is stated.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

Above a concentration that can be read off a chart, the liver fails in most people unless the antidote is given.

primary_references

[apap-p36191122] Point-of-Care Testing and N-Acetylcysteine for Acute Acetaminophen Overdose (2021). https://pubmed.ncbi.nlm.nih.gov/36191122/

tissue_or_cell_type

Liver

trigger_kind

biomarker_context Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 428–439

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Review of point-of-care testing and antidote guidance for acute overdose · source_derived_draft · unverified_draft

### apap-the-nomogram-and-the-antidote Acetaminophen overdose is the leading cause of acute liver failure in Canada and around the world with approximately 4,500 hospitalisations each year in Canada and about 6% of those hospitalised developing liver injury including acute liver failure that may require transplant or lead to death, and on the Rumack-Matthew nomogram derived from patients not treated with antidote a serum concentration above 200 milligrams per litre at 4 hours carries a 60% incidence of severe hepatotoxicity and 5% mortality rising to 90% and 24% at 300 milligrams per litre, with treatment by N-acetylcysteine required above 140 milligrams per litre at 4 hours. Condition category: biomarker_context nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Above a concentration that can be read off a chart, the liver fails in most people unless the antidote is given. organism: Human tissue_or_cell_type: Liver experimental_model: Review of point-of-care testing and antidote guidance for acute overdose limitations: A health-technology review rather than primary research. The nomogram figures it quotes are derived from patients not treated with antidote, which is stated. exposure: Serum acetaminophen concentration interpreted against the Rumack-Matthew nomogram evidence_span: {"source_cache": "artifacts/paracetamol-research/36191122.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "859db1958aeb26b75a34a32e4dd1c4713dc7db413717cefe62a3659856db7568", "start_char": 0, "end_char": 3325, "text_sha256": "859db1958aeb26b75a34a32e4dd1c4713dc7db413717cefe62a3659856db7568"} [apap-p36191122] Point-of-Care Testing and N-Acetylcysteine for Acute Acetaminophen Overdose (2021). https://pubmed.ncbi.nlm.nih.gov/36191122/

evidence_span

{"source_cache": "artifacts/paracetamol-research/11113024.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f3d9785240d2bc30e79775035576d3b017471500c110d627653e6fd80e820eee", "start_char": 0, "end_char": 1012, "text_sha256": "f3d9785240d2bc30e79775035576d3b017471500c110d627653e6fd80e820eee"}

experimental_model

Review of the evidence for an unidentified cyclooxygenase form, written before COX-3 was cloned

exposure

Acetaminophen compared against its effects on urinary prostaglandin metabolites and on platelet and gastric prostaglandin synthesis

limitations

A review that states the puzzle precisely before an answer existed. The human observations it collects are the clinical signature any mechanism has to explain.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human and animal

plain_language

It lowers prostaglandins measured in urine while leaving the platelet and the stomach alone, and that is the puzzle every account has to solve.

primary_references

[apap-p11113024] Mechanism of action of acetaminophen: is there a cyclooxygenase 3? (2000). https://pubmed.ncbi.nlm.nih.gov/11113024/ DOI: 10.1086/317520

tissue_or_cell_type

Platelets, gastric mucosa and tissue homogenates

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 207–218

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Review of the evidence for an unidentified cyclooxygenase form, written before COX-3 was cloned · source_derived_draft · unverified_draft

### apap-the-puzzle-stated Acetaminophen has potent antipyretic and analgesic actions but very weak anti-inflammatory activity, and when administered to humans it reduces levels of prostaglandin metabolites in urine but does not reduce synthesis of prostaglandins by blood platelets or by the stomach mucosa; because it is a weak inhibitor in vitro of both cyclooxygenase-1 and -2 the possibility exists that it inhibits a so far unidentified form, and in animal studies cyclooxygenase in homogenates of different tissues varies in sensitivity to its inhibitory action, which may be evidence that there are more than two isoforms. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: It lowers prostaglandins measured in urine while leaving the platelet and the stomach alone, and that is the puzzle every account has to solve. organism: Human and animal tissue_or_cell_type: Platelets, gastric mucosa and tissue homogenates experimental_model: Review of the evidence for an unidentified cyclooxygenase form, written before COX-3 was cloned limitations: A review that states the puzzle precisely before an answer existed. The human observations it collects are the clinical signature any mechanism has to explain. exposure: Acetaminophen compared against its effects on urinary prostaglandin metabolites and on platelet and gastric prostaglandin synthesis evidence_span: {"source_cache": "artifacts/paracetamol-research/11113024.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f3d9785240d2bc30e79775035576d3b017471500c110d627653e6fd80e820eee", "start_char": 0, "end_char": 1012, "text_sha256": "f3d9785240d2bc30e79775035576d3b017471500c110d627653e6fd80e820eee"} [apap-p11113024] Mechanism of action of acetaminophen: is there a cyclooxygenase 3? (2000). https://pubmed.ncbi.nlm.nih.gov/11113024/ DOI: 10.1086/317520

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/paracetamol-research/10400483.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7ea713edb6955db38992c5372794d93c0d52f841d3f8897817286f7f66d28605", "start_char": 0, "end_char": 2662, "text_sha256": "7ea713edb6955db38992c5372794d93c0d52f841d3f8897817286f7f66d28605"}

experimental_model

Elective oral challenges in 256 patients with a history of pseudoallergic skin reactions to non-steroidal anti-inflammatory drugs

exposure

Increasing doses of acetaminophen and nimesulide across three patient groups

limitations

A large challenge series that puts a rate on the cross-reactivity and identifies risk factors. Patients were selected for a history of reacting, so the rates apply to that population and not to the general one.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

One patient in five who reacts to aspirin also reacts to paracetamol, so it is not automatically the safe substitute.

primary_references

[apap-p10400483] Risk factors for acetaminophen and nimesulide intolerance in patients with NSAID-induced skin disorders. (1999). https://pubmed.ncbi.nlm.nih.gov/10400483/ DOI: 10.1016/s1081-1206(10)63166-3

tissue_or_cell_type

Skin

trigger_kind

biomarker_context Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 467–478

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Elective oral challenges in 256 patients with a history of pseudoallergic skin reactions to non-steroidal anti-inflammatory drugs · source_derived_draft · unverified_draft

### apap-twenty-percent-cross-react Of 256 patients with a history of recent pseudoallergic skin reactions caused by non-steroidal anti-inflammatory drugs who underwent elective oral challenges, 48 or 19% reacted to acetaminophen or nimesulide, with similar proportions among those with chronic urticaria at 23% and otherwise normal subjects with a history of aspirin-induced urticaria at 19% while pyrazolone-intolerant patients showed the lowest number at 4%, aspirin intolerance was a risk factor for acetaminophen or nimesulide induced urticaria with a relative risk of 5.4, a history of anaphylactoid reactions carried a relative risk of 5.7, and atopy raised reactivity to nimesulide from 9 to 23%. Condition category: biomarker_context nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: One patient in five who reacts to aspirin also reacts to paracetamol, so it is not automatically the safe substitute. organism: Human tissue_or_cell_type: Skin experimental_model: Elective oral challenges in 256 patients with a history of pseudoallergic skin reactions to non-steroidal anti-inflammatory drugs limitations: A large challenge series that puts a rate on the cross-reactivity and identifies risk factors. Patients were selected for a history of reacting, so the rates apply to that population and not to the general one. exposure: Increasing doses of acetaminophen and nimesulide across three patient groups evidence_span: {"source_cache": "artifacts/paracetamol-research/10400483.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7ea713edb6955db38992c5372794d93c0d52f841d3f8897817286f7f66d28605", "start_char": 0, "end_char": 2662, "text_sha256": "7ea713edb6955db38992c5372794d93c0d52f841d3f8897817286f7f66d28605"} [apap-p10400483] Risk factors for acetaminophen and nimesulide intolerance in patients with NSAID-induced skin disorders. (1999). https://pubmed.ncbi.nlm.nih.gov/10400483/ DOI: 10.1016/s1081-1206(10)63166-3

evidence_span

{"source_cache": "artifacts/glutathione-research/6424115.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08", "start_char": 0, "end_char": 1307, "text_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08"}

experimental_model

Enzyme oxidation and radiolabeled binding assays

exposure

NAPQI or acetaminophen with reductants

limitations

Experimental chemistry; no new human dose threshold or treatment regimen is inferred.

nutrient_topic

Glutathione research collection; topical membership is not evidence of a direct dietary effect. · GSH

organism

Mouse microsomes and cell-free cytochrome-P450 system

plain_language

The parent drug and its reactive metabolite are separate chemical entities.

primary_references

[glutathione-p6424115] N-acetyl-p-benzoquinone imine: a cytochrome P-450-mediated oxidation product of acetaminophen. (1984). https://pubmed.ncbi.nlm.nih.gov/6424115/ DOI: 10.1073/pnas.81.5.1327

tissue_or_cell_type

Acetaminophen reactive-metabolite handling

Glutathione: metabolism, signaling and nutrient connections (2026-09-17) · lines 1048–1059

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Enzyme oxidation and radiolabeled binding assays · source_derived_draft · unverified_draft

### glutathione-acetaminophen-napqi Cytochrome-P450-mediated acetaminophen oxidation produced NAPQI in the experimental oxidation system. Condition category: normal nutrient_topic: Glutathione research collection; topical membership is not evidence of a direct dietary effect. plain_language: The parent drug and its reactive metabolite are separate chemical entities. organism: Mouse microsomes and cell-free cytochrome-P450 system tissue_or_cell_type: Acetaminophen reactive-metabolite handling experimental_model: Enzyme oxidation and radiolabeled binding assays limitations: Experimental chemistry; no new human dose threshold or treatment regimen is inferred. exposure: NAPQI or acetaminophen with reductants evidence_span: {"source_cache": "artifacts/glutathione-research/6424115.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08", "start_char": 0, "end_char": 1307, "text_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08"} [glutathione-p6424115] N-acetyl-p-benzoquinone imine: a cytochrome P-450-mediated oxidation product of acetaminophen. (1984). https://pubmed.ncbi.nlm.nih.gov/6424115/ DOI: 10.1073/pnas.81.5.1327

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/paracetamol-research/12011469.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d", "start_char": 0, "end_char": 1561, "text_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d"}

experimental_model

Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition

exposure

Acetaminophen with 2 micromolar arachidonic acid, and with prostaglandin G2, 12-hydroperoxyeicosatetraenoic acid or tert-butyl hydroperoxide added back

limitations

The decisive record of the chapter: it measures a 435-fold difference between two human cell types, shows it is not isoform selectivity, and reverses it by adding the peroxide back.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Human

plain_language

Put the peroxide back and the drug stops working, which is why the platelet is untouched.

primary_references

[apap-p12011469] Determinants of the cellular specificity of acetaminophen as an inhibitor of prostaglandin H(2) synthases. (2002). https://pubmed.ncbi.nlm.nih.gov/12011469/ DOI: 10.1073/pnas.102588199

tissue_or_cell_type

Endothelium and platelets

trigger_kind

biomarker_context Imported condition classification; unverified.

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 103–114

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition · source_derived_draft · unverified_draft

### apap-peroxide-reverses-it Increasing the peroxide product of the cyclooxygenase, prostaglandin G2, by elevating the concentration of either enzyme or substrate reverses the inhibitory action of acetaminophen, as does adding prostaglandin G2 itself, 0.3 micromolar 12-hydroperoxyeicosatetraenoic acid which is a major product of the platelet completely reverses the action on synthase-1, and inhibition in endothelial cells is abrogated by tert-butyl hydroperoxide, supporting the hypothesis that hydroperoxide concentration contributes to the cellular selectivity. Condition category: biomarker_context nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Put the peroxide back and the drug stops working, which is why the platelet is untouched. organism: Human tissue_or_cell_type: Endothelium and platelets experimental_model: Interleukin-1-alpha-stimulated human endothelial cells and human platelets compared, with hydroperoxide addition limitations: The decisive record of the chapter: it measures a 435-fold difference between two human cell types, shows it is not isoform selectivity, and reverses it by adding the peroxide back. exposure: Acetaminophen with 2 micromolar arachidonic acid, and with prostaglandin G2, 12-hydroperoxyeicosatetraenoic acid or tert-butyl hydroperoxide added back evidence_span: {"source_cache": "artifacts/paracetamol-research/12011469.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d", "start_char": 0, "end_char": 1561, "text_sha256": "7e599890f658a63c52471fbc7e6853d7db6a5ecbe892241a39c8a633b3ab2d0d"} [apap-p12011469] Determinants of the cellular specificity of acetaminophen as an inhibitor of prostaglandin H(2) synthases. (2002). https://pubmed.ncbi.nlm.nih.gov/12011469/ DOI: 10.1073/pnas.102588199

evidence_span

{"source_cache": "artifacts/paracetamol-research/12538810.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "23bbb8a6c280cfcae85e304695c2a93f2c748c804befc1e006f415f4f8dfaed0", "start_char": 0, "end_char": 1592, "text_sha256": "23bbb8a6c280cfcae85e304695c2a93f2c748c804befc1e006f415f4f8dfaed0"}

experimental_model

Prostaglandin H synthase inhibition by salicylate compared with phenolic inhibitors, using manganese-reconstituted enzyme

exposure

Salicylate and benzoic acid analogues, with 12-hydroperoxyeicosatetraenoic acid and prostaglandin G2

limitations

Recorded here because it separates paracetamol from salicylate mechanistically while showing both are peroxide-sensitive. The work is on salicylate, which is stated on the claim.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Enzyme

plain_language

Two drugs that both stop working when peroxide is high, reaching that point by different routes.

primary_references

[apap-p12538810] Inhibition of prostaglandin H2 synthases by salicylate is dependent on the oxidative state of the enzymes. (2003). https://pubmed.ncbi.nlm.nih.gov/12538810/ DOI: 10.1124/jpet.102.042853

tissue_or_cell_type

Prostaglandin H synthase

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 168–179

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prostaglandin H synthase inhibition by salicylate compared with phenolic inhibitors, using manganese-reconstituted enzyme · source_derived_draft · unverified_draft

### apap-salicylate-is-not-a-cosubstrate Salicylate inhibits prostaglandin H synthase-1 and -2 with a potency inversely related to ambient hydroperoxide concentrations and its inhibition of synthase-1 was prevented by 12-hydroperoxyeicosatetraenoic acid, but unlike typical phenolic inhibitors such as acetaminophen, salicylate was ineffective as a reducing cosubstrate for the peroxidase activity, implicating the cyclooxygenase site as its target; 12-HPETE does not prevent inhibition of the manganese-reconstituted enzyme by salicylate, indicating that reversal by hydroperoxides depends on electron transfer between the cyclooxygenase and peroxidase active sites. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Two drugs that both stop working when peroxide is high, reaching that point by different routes. organism: Enzyme tissue_or_cell_type: Prostaglandin H synthase experimental_model: Prostaglandin H synthase inhibition by salicylate compared with phenolic inhibitors, using manganese-reconstituted enzyme limitations: Recorded here because it separates paracetamol from salicylate mechanistically while showing both are peroxide-sensitive. The work is on salicylate, which is stated on the claim. exposure: Salicylate and benzoic acid analogues, with 12-hydroperoxyeicosatetraenoic acid and prostaglandin G2 evidence_span: {"source_cache": "artifacts/paracetamol-research/12538810.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "23bbb8a6c280cfcae85e304695c2a93f2c748c804befc1e006f415f4f8dfaed0", "start_char": 0, "end_char": 1592, "text_sha256": "23bbb8a6c280cfcae85e304695c2a93f2c748c804befc1e006f415f4f8dfaed0"} [apap-p12538810] Inhibition of prostaglandin H2 synthases by salicylate is dependent on the oxidative state of the enzymes. (2003). https://pubmed.ncbi.nlm.nih.gov/12538810/ DOI: 10.1124/jpet.102.042853

evidence_span

{"source_cache": "artifacts/curcumin-research/22725836.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "255db8a54957c442fe6fca1d21aafe393e3a5506bec7330b49e1bb6f85d86127", "start_char": 0, "end_char": 1977, "text_sha256": "255db8a54957c442fe6fca1d21aafe393e3a5506bec7330b49e1bb6f85d86127"}

experimental_model

Randomized six-way crossover in eight healthy volunteers

exposure

4 g curcuminoids plus 24 mg piperine, four doses over two days before each probe drug

limitations

Short regimen and small sample. A null result for these probes does not establish no interactions with all medicines or preparations.

nutrient_topic

Curcumin research collection; topical membership is not evidence of a direct dietary effect. · Curcumin

organism

Homo sapiens

plain_language

The conjugation probe did not reproduce the in-vitro prediction.

primary_references

[curcumin-p22725836] Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers. (2013). https://pubmed.ncbi.nlm.nih.gov/22725836/ DOI: 10.1111/j.1365-2125.2012.04364.x

tissue_or_cell_type

Drug pharmacokinetics

Curcumin: metabolism, signaling and nutrient connections (2026-09-17) · lines 944–955

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized six-way crossover in eight healthy volunteers · source_derived_draft · unverified_draft

### curcumin-acetaminophen-null No meaningful overall acetaminophen pharmacokinetic change was found. Condition category: normal nutrient_topic: Curcumin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The conjugation probe did not reproduce the in-vitro prediction. organism: Homo sapiens tissue_or_cell_type: Drug pharmacokinetics experimental_model: Randomized six-way crossover in eight healthy volunteers limitations: Short regimen and small sample. A null result for these probes does not establish no interactions with all medicines or preparations. exposure: 4 g curcuminoids plus 24 mg piperine, four doses over two days before each probe drug evidence_span: {"source_cache": "artifacts/curcumin-research/22725836.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "255db8a54957c442fe6fca1d21aafe393e3a5506bec7330b49e1bb6f85d86127", "start_char": 0, "end_char": 1977, "text_sha256": "255db8a54957c442fe6fca1d21aafe393e3a5506bec7330b49e1bb6f85d86127"} [curcumin-p22725836] Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers. (2013). https://pubmed.ncbi.nlm.nih.gov/22725836/ DOI: 10.1111/j.1365-2125.2012.04364.x

availability_state

biomarker_context Imported condition classification; unverified.

evidence_access

Primary abstract

experimental_model

Human predose/postdose urine NMR after a standard acetaminophen dose.

limitations

The authors proposed competition for O-sulfonation; the association does not prove tyrosine intake depletes sulfate or increases drug toxicity.

nutrient_topic

L-Tyrosine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Tyrosine

plain_language

Microbial metabolism can correlate with how a drug is processed.

primary_references

Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19667173/ · DOI 10.1073/pnas.0904489106

trigger_kind

biomarker_context Imported condition classification; unverified.

L-Tyrosine: catecholamines, thyroid chemistry, pigment, metabolism and cross-nutrient mechanisms (2026-09-19) · lines 372–378

AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human predose/postdose urine NMR after a standard acetaminophen dose. · source_derived_draft · unverified_draft

## l-tyrosine-cresol-drug-sulfation Microbial metabolism can correlate with how a drug is processed. Higher predose urinary p-cresol sulfate was associated with a lower postdose acetaminophen sulfate-to-glucuronide ratio. Model: Human predose/postdose urine NMR after a standard acetaminophen dose. Limitations: The authors proposed competition for O-sulfonation; the association does not prove tyrosine intake depletes sulfate or increases drug toxicity. Evidence access: Primary abstract Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19667173/ · DOI 10.1073/pnas.0904489106

evidence_span

{"source_cache": "artifacts/paracetamol-research/15650114.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1661f4d2b21244e0fc16b9a3b947cf4d09d39be35367ed263cce441f43a60563", "start_char": 0, "end_char": 1473, "text_sha256": "1661f4d2b21244e0fc16b9a3b947cf4d09d39be35367ed263cce441f43a60563"}

experimental_model

Cloning and sequencing of rat COX-1b from cerebral endothelial cells with transfection and antibody generation

exposure

Rat COX-1b complementary DNA transfected into COS-7 cells, assayed for activity and for effect on acetaminophen inhibition

limitations

Tests the proposal in a second species by building the protein and asking whether it works. The protein is detected in rat tissue, so the finding is that it exists and is not a cyclooxygenase.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Rat

plain_language

In the rat the retained intron shifts the reading frame, so what is made is a different protein altogether and not an enzyme.

primary_references

[apap-p15650114] Cloning and characterization of cyclooxygenase-1b (putative cyclooxygenase-3) in rat. (2005). https://pubmed.ncbi.nlm.nih.gov/15650114/ DOI: 10.1124/jpet.104.079533

tissue_or_cell_type

Cerebral endothelial cells

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 220–231

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cloning and sequencing of rat COX-1b from cerebral endothelial cells with transfection and antibody generation · source_derived_draft · unverified_draft

### apap-frameshift-makes-a-different-protein The 98 base pair intron 1 of the cyclooxygenase-1 gene remains unprocessed in rat COX-1b messenger RNA, causing a frameshift mutation and a 127 amino acid open reading frame with no sequence similarity with known cyclooxygenases, and transfection of COS-7 cells produced a protein of the expected size which was also detected in rat tissues with highest expression in heart, kidney and neuronal tissue, but rat COX-1b does not have cyclooxygenase activity and does not have any effect on the inhibition of prostaglandin production by acetaminophen, leading the authors to propose the name cyclooxygenase variant protein instead. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: In the rat the retained intron shifts the reading frame, so what is made is a different protein altogether and not an enzyme. organism: Rat tissue_or_cell_type: Cerebral endothelial cells experimental_model: Cloning and sequencing of rat COX-1b from cerebral endothelial cells with transfection and antibody generation limitations: Tests the proposal in a second species by building the protein and asking whether it works. The protein is detected in rat tissue, so the finding is that it exists and is not a cyclooxygenase. exposure: Rat COX-1b complementary DNA transfected into COS-7 cells, assayed for activity and for effect on acetaminophen inhibition evidence_span: {"source_cache": "artifacts/paracetamol-research/15650114.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1661f4d2b21244e0fc16b9a3b947cf4d09d39be35367ed263cce441f43a60563", "start_char": 0, "end_char": 1473, "text_sha256": "1661f4d2b21244e0fc16b9a3b947cf4d09d39be35367ed263cce441f43a60563"} [apap-p15650114] Cloning and characterization of cyclooxygenase-1b (putative cyclooxygenase-3) in rat. (2005). https://pubmed.ncbi.nlm.nih.gov/15650114/ DOI: 10.1124/jpet.104.079533

evidence_span

{"source_cache": "artifacts/paracetamol-research/3124965.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502", "start_char": 0, "end_char": 2236, "text_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502"}

experimental_model

Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation

exposure

Acetaminophen from 20 micromolar to above 10 millimolar, with glutathione, ascorbate and indomethacin

limitations

Shows that the drug both stimulates and inhibits the same enzyme depending on concentration, and that the enzyme makes NAPQI from it. A microsomal preparation at concentrations far above therapeutic.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Sheep

plain_language

The prostaglandin enzyme can itself turn the drug into the liver-damaging metabolite.

primary_references

[apap-p3124965] Acetaminophen and analogs as cosubstrates and inhibitors of prostaglandin H synthase. (1988). https://pubmed.ncbi.nlm.nih.gov/3124965/ DOI: 10.1016/0009-2797(88)90101-9

tissue_or_cell_type

Seminal vesicle microsomes

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 129–140

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation · source_derived_draft · unverified_draft

### apap-the-enzyme-makes-napqi Using acetaminophen as a probe, at low concentrations it is converted in a cooxidation reaction with arachidonic acid to the dimer 4,4-dihydroxy-3,3-biacetanilide and other polymeric products, and the electrophilic metabolite N-acetyl-p-benzoquinone imine was detected directly and indirectly by its reaction with glutathione to form 3-S-glutathionylacetaminophen; the same products were formed by the synthase with hydrogen peroxide in reactions not inhibited by indomethacin, and formation of all products was inhibited by ascorbic acid and butylated hydroxyanisole. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: The prostaglandin enzyme can itself turn the drug into the liver-damaging metabolite. organism: Sheep tissue_or_cell_type: Seminal vesicle microsomes experimental_model: Ram seminal vesicle microsomal prostaglandin H synthase with product identification by cooxidation limitations: Shows that the drug both stimulates and inhibits the same enzyme depending on concentration, and that the enzyme makes NAPQI from it. A microsomal preparation at concentrations far above therapeutic. exposure: Acetaminophen from 20 micromolar to above 10 millimolar, with glutathione, ascorbate and indomethacin evidence_span: {"source_cache": "artifacts/paracetamol-research/3124965.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502", "start_char": 0, "end_char": 2236, "text_sha256": "dcc85a1ab66984973092042b5553f43fbbe5eb10b674614c9b1fa991b3969502"} [apap-p3124965] Acetaminophen and analogs as cosubstrates and inhibitors of prostaglandin H synthase. (1988). https://pubmed.ncbi.nlm.nih.gov/3124965/ DOI: 10.1016/0009-2797(88)90101-9

evidence_span

{"source_cache": "artifacts/paracetamol-research/23940628.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cc9d85547497bfdf88095aaeccf5a11cb9198140ebb35523d5da1b85f76e0a44", "start_char": 0, "end_char": 2208, "text_sha256": "cc9d85547497bfdf88095aaeccf5a11cb9198140ebb35523d5da1b85f76e0a44"}

experimental_model

Metabolite formation and antinociception for 4-aminophenol and a vanillylamine analogue across knockouts and pharmacological blockade

exposure

Systemic 4-aminophenol and 4-hydroxy-3-methoxybenzylamine, with fatty acid amide hydrolase, TRPV1, cannabinoid and serotonergic manipulations

limitations

The broadest test of the route: it reconstructs the whole chain from metabolite formation to descending pathway, and shows the profile of the metabolite matches that of the parent drug.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Mouse and rat

plain_language

Every step of the proposed chain was cut in turn, and cutting any of them stopped the painkilling.

primary_references

[apap-p23940628] Fatty acid amide hydrolase-dependent generation of antinociceptive drug metabolites acting on TRPV1 in the brain. (2013). https://pubmed.ncbi.nlm.nih.gov/23940628/ DOI: 10.1371/journal.pone.0070690

tissue_or_cell_type

Brain and spinal cord

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 324–335

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Metabolite formation and antinociception for 4-aminophenol and a vanillylamine analogue across knockouts and pharmacological blockade · source_derived_draft · unverified_draft

### apap-the-whole-chain Systemic 4-aminophenol and 4-hydroxy-3-methoxybenzylamine led to dose-dependent formation of AM404 and of arvanil and olvanil respectively in the mouse brain, the order of potency of these lipid metabolites as TRPV1 activators being arvanil equal to olvanil much greater than AM404, both parent amines displayed antinociceptive activity in rodent pain tests, formation of these metabolites and the antinociceptive effects were substantially reduced or disappeared in fatty acid amide hydrolase null mice, activity was lost in TRPV1 null mice, intracerebroventricular capsazepine eliminated the effects, and in the rat, inhibition of fatty acid amide hydrolase, TRPV1, cannabinoid CB1 receptors and spinal 5-HT3 or 5-HT1A receptors and chemical deletion of bulbospinal serotonergic pathways all prevented the action, giving a pharmacological profile identical to that previously reported for paracetamol. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Every step of the proposed chain was cut in turn, and cutting any of them stopped the painkilling. organism: Mouse and rat tissue_or_cell_type: Brain and spinal cord experimental_model: Metabolite formation and antinociception for 4-aminophenol and a vanillylamine analogue across knockouts and pharmacological blockade limitations: The broadest test of the route: it reconstructs the whole chain from metabolite formation to descending pathway, and shows the profile of the metabolite matches that of the parent drug. exposure: Systemic 4-aminophenol and 4-hydroxy-3-methoxybenzylamine, with fatty acid amide hydrolase, TRPV1, cannabinoid and serotonergic manipulations evidence_span: {"source_cache": "artifacts/paracetamol-research/23940628.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cc9d85547497bfdf88095aaeccf5a11cb9198140ebb35523d5da1b85f76e0a44", "start_char": 0, "end_char": 2208, "text_sha256": "cc9d85547497bfdf88095aaeccf5a11cb9198140ebb35523d5da1b85f76e0a44"} [apap-p23940628] Fatty acid amide hydrolase-dependent generation of antinociceptive drug metabolites acting on TRPV1 in the brain. (2013). https://pubmed.ncbi.nlm.nih.gov/23940628/ DOI: 10.1371/journal.pone.0070690

evidence_span

{"source_cache": "artifacts/paracetamol-research/16438952.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8fe3f4535ff4a14c2e417850a583722fc34262e925952ff2fdd9fe244c7e218f", "start_char": 0, "end_char": 509, "text_sha256": "8fe3f4535ff4a14c2e417850a583722fc34262e925952ff2fdd9fe244c7e218f"}

experimental_model

Hot plate test in rats with two cannabinoid receptor antagonists

exposure

Paracetamol with AM281 and SR141716A at doses that prevent the action of a cannabinoid agonist

limitations

A short report with the antagonist doses anchored to a positive control. One pain test in one species.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Rat

plain_language

Two different blockers of the cannabinoid receptor each stopped the painkiller working.

primary_references

[apap-p16438952] The analgesic activity of paracetamol is prevented by the blockade of cannabinoid CB1 receptors. (2006). https://pubmed.ncbi.nlm.nih.gov/16438952/ DOI: 10.1016/j.ejphar.2005.12.015

tissue_or_cell_type

Whole animal

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 350–361

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Hot plate test in rats with two cannabinoid receptor antagonists · source_derived_draft · unverified_draft

### apap-two-antagonists-block-it In rats using the hot plate test the analgesic effect of paracetamol was prevented by two antagonists at cannabinoid CB1 receptors, AM281 and SR141716A, at doses that prevent the analgesic activity of the cannabinoid CB1 agonist HU210, suggesting that paracetamol-induced antinociception involves the cannabinoid system. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Two different blockers of the cannabinoid receptor each stopped the painkiller working. organism: Rat tissue_or_cell_type: Whole animal experimental_model: Hot plate test in rats with two cannabinoid receptor antagonists limitations: A short report with the antagonist doses anchored to a positive control. One pain test in one species. exposure: Paracetamol with AM281 and SR141716A at doses that prevent the action of a cannabinoid agonist evidence_span: {"source_cache": "artifacts/paracetamol-research/16438952.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8fe3f4535ff4a14c2e417850a583722fc34262e925952ff2fdd9fe244c7e218f", "start_char": 0, "end_char": 509, "text_sha256": "8fe3f4535ff4a14c2e417850a583722fc34262e925952ff2fdd9fe244c7e218f"} [apap-p16438952] The analgesic activity of paracetamol is prevented by the blockade of cannabinoid CB1 receptors. (2006). https://pubmed.ncbi.nlm.nih.gov/16438952/ DOI: 10.1016/j.ejphar.2005.12.015

evidence_span

{"source_cache": "artifacts/paracetamol-research/15879007.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "857ae81119eac4c47a63027afa15fde1b0099c377c0d444e13da087ea71dec86", "start_char": 0, "end_char": 807, "text_sha256": "857ae81119eac4c47a63027afa15fde1b0099c377c0d444e13da087ea71dec86"}

experimental_model

Critical review of the COX-3 literature

exposure

Evaluation of the expression levels, kinetics and species differences of the proposed isoform

limitations

A review rather than new data. It states the species-specific reason the proposal fails and the reason it would not matter even where the protein is active.

nutrient_topic

Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. · Paracetamol

organism

Dog, rodent and human

plain_language

Even in the dog the amounts are too small to matter, and in people the protein is not an enzyme.

primary_references

[apap-p15879007] Acetaminophen and the cyclooxygenase-3 puzzle: sorting out facts, fictions, and uncertainties. (2005). https://pubmed.ncbi.nlm.nih.gov/15879007/ DOI: 10.1124/jpet.105.085431

tissue_or_cell_type

Cyclooxygenase variants

Paracetamol: the enzyme it reduces rather than blocks, the isoform that turned out not to exist, the metabolite that carries the analgesia, and the metabolite that destroys the liver (2026-09-22) · lines 246–257

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Critical review of the COX-3 literature · source_derived_draft · unverified_draft

### apap-unlikely-in-any-species Although COX-3 might have cyclooxygenase activity in canines and that activity might be inhibited by acetaminophen, its low expression level and the kinetics indicate unlikely clinical relevance, and in rodents and humans COX-3 encodes proteins with completely different amino acid sequences than cyclooxygenase-1 or -2 and without cyclooxygenase activity, so it is improbable that it plays a role in prostaglandin-mediated fever and pain in these species. Condition category: normal nutrient_topic: Paracetamol research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from the metabolites NAPQI and AM404. plain_language: Even in the dog the amounts are too small to matter, and in people the protein is not an enzyme. organism: Dog, rodent and human tissue_or_cell_type: Cyclooxygenase variants experimental_model: Critical review of the COX-3 literature limitations: A review rather than new data. It states the species-specific reason the proposal fails and the reason it would not matter even where the protein is active. exposure: Evaluation of the expression levels, kinetics and species differences of the proposed isoform evidence_span: {"source_cache": "artifacts/paracetamol-research/15879007.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "857ae81119eac4c47a63027afa15fde1b0099c377c0d444e13da087ea71dec86", "start_char": 0, "end_char": 807, "text_sha256": "857ae81119eac4c47a63027afa15fde1b0099c377c0d444e13da087ea71dec86"} [apap-p15879007] Acetaminophen and the cyclooxygenase-3 puzzle: sorting out facts, fictions, and uncertainties. (2005). https://pubmed.ncbi.nlm.nih.gov/15879007/ DOI: 10.1124/jpet.105.085431

evidence_span

{"source_cache": "artifacts/glutathione-research/6424115.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08", "start_char": 0, "end_char": 1307, "text_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08"}

experimental_model

Enzyme oxidation and radiolabeled binding assays

exposure

NAPQI or acetaminophen with reductants

limitations

Cell-free/microsomal finding; vitamin C is not established here as a clinical antidote.

nutrient_topic

Glutathione research collection; topical membership is not evidence of a direct dietary effect. · GSH

organism

Mouse microsomes and cell-free cytochrome-P450 system

plain_language

Different reductants changed the same reactive intermediate by different chemistry.

primary_references

[glutathione-p6424115] N-acetyl-p-benzoquinone imine: a cytochrome P-450-mediated oxidation product of acetaminophen. (1984). https://pubmed.ncbi.nlm.nih.gov/6424115/ DOI: 10.1073/pnas.81.5.1327

tissue_or_cell_type

Acetaminophen reactive-metabolite handling

Glutathione: metabolism, signaling and nutrient connections (2026-09-17) · lines 1061–1072

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Enzyme oxidation and radiolabeled binding assays · source_derived_draft · unverified_draft

### glutathione-napqi-ascorbate Ascorbic acid decreased binding through reduction of NAPQI to acetaminophen in the comparison. Condition category: normal nutrient_topic: Glutathione research collection; topical membership is not evidence of a direct dietary effect. plain_language: Different reductants changed the same reactive intermediate by different chemistry. organism: Mouse microsomes and cell-free cytochrome-P450 system tissue_or_cell_type: Acetaminophen reactive-metabolite handling experimental_model: Enzyme oxidation and radiolabeled binding assays limitations: Cell-free/microsomal finding; vitamin C is not established here as a clinical antidote. exposure: NAPQI or acetaminophen with reductants evidence_span: {"source_cache": "artifacts/glutathione-research/6424115.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08", "start_char": 0, "end_char": 1307, "text_sha256": "8c45563e89388d200eb64ae63d12b388ef5cca91369a585157ef27b39f525b08"} [glutathione-p6424115] N-acetyl-p-benzoquinone imine: a cytochrome P-450-mediated oxidation product of acetaminophen. (1984). https://pubmed.ncbi.nlm.nih.gov/6424115/ DOI: 10.1073/pnas.81.5.1327