Component

Naproxen

Naproxen. Species, exposure and limitations are retained in each linked claim.

5 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Although ibuprofen, naproxen and celecoxib all had the potential to compete with aspirin for access to the substrate binding channel of cyclooxygenase-1 in vitro, measuring aspirin target engagement directly by mass spectrometry after a single therapeutic dose of each followed by 325 milligrams of aspirin revealed a potent drug-drug interaction between ibuprofen and aspirin and between naproxen and aspirin but not between celecoxib and aspirin.

    Naproxen → Aspirin / acetylsalicylic acid source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/aspirin-research/25385584.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b2de8f18887f336c8c735f7ffbd1b72b92e5da43aa6388c229590dea120439f2", "start_char": 0, "end_char": 1242, "text_sha256": "b2de8f18887f336c8c735f7ffbd1b72b92e5da43aa6388c229590dea120439f2"}
    experimental_model
    Mass-spectrometric assay of cyclooxygenase-1 acetylation in platelets from volunteers given an NSAID followed by aspirin
    exposure
    A single therapeutic dose of ibuprofen, naproxen or celecoxib followed by 325 milligrams of aspirin
    limitations
    Measures target engagement directly rather than inferring it from platelet function, and separates the drugs. A single dose of each, in volunteers rather than patients.
    nutrient_topic
    Aspirin research collection; topical membership is not evidence of a direct clinical effect, and aspirin is recorded separately from salicylate, the metabolite it becomes. · Aspirin / acetylsalicylic acid
    organism
    Human
    plain_language
    Ibuprofen and naproxen block aspirin in people; celecoxib does not.
    primary_references
    [asa-p25385584] Differential impairment of aspirin-dependent platelet cyclooxygenase acetylation by nonsteroidal antiinflammatory drugs. (2014). https://pubmed.ncbi.nlm.nih.gov/25385584/ DOI: 10.1073/pnas.1406997111
    tissue_or_cell_type
    Platelets
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Aspirin: the serine it acetylates, the enzyme that acetylation creates, the dose that separates platelet from vessel wall, and the metabolite that is a different drug (2026-09-22) · lines 455–466

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mass-spectrometric assay of cyclooxygenase-1 acetylation in platelets from volunteers given an NSAID followed by aspirin · source_derived_draft · unverified_draft

    ### asa-which-nsaids-interact Although ibuprofen, naproxen and celecoxib all had the potential to compete with aspirin for access to the substrate binding channel of cyclooxygenase-1 in vitro, measuring aspirin target engagement directly by mass spectrometry after a single therapeutic dose of each followed by 325 milligrams of aspirin revealed a potent drug-drug interaction between ibuprofen and aspirin and between naproxen and aspirin but not between celecoxib and aspirin. Condition category: biomarker_context nutrient_topic: Aspirin research collection; topical membership is not evidence of a direct clinical effect, and aspirin is recorded separately from salicylate, the metabolite it becomes. plain_language: Ibuprofen and naproxen block aspirin in people; celecoxib does not. organism: Human tissue_or_cell_type: Platelets experimental_model: Mass-spectrometric assay of cyclooxygenase-1 acetylation in platelets from volunteers given an NSAID followed by aspirin limitations: Measures target engagement directly rather than inferring it from platelet function, and separates the drugs. A single dose of each, in volunteers rather than patients. exposure: A single therapeutic dose of ibuprofen, naproxen or celecoxib followed by 325 milligrams of aspirin evidence_span: {"source_cache": "artifacts/aspirin-research/25385584.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b2de8f18887f336c8c735f7ffbd1b72b92e5da43aa6388c229590dea120439f2", "start_char": 0, "end_char": 1242, "text_sha256": "b2de8f18887f336c8c735f7ffbd1b72b92e5da43aa6388c229590dea120439f2"} [asa-p25385584] Differential impairment of aspirin-dependent platelet cyclooxygenase acetylation by nonsteroidal antiinflammatory drugs. (2014). https://pubmed.ncbi.nlm.nih.gov/25385584/ DOI: 10.1073/pnas.1406997111
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. The time-dependent reduction in potency of anandamide toward inhibition of cannabinoid agonist binding in rat cerebellar membranes was blocked by ibuprofen but not by acetylsalicylic acid, sulindac, acetaminophen or to any significant extent by ketoprofen and naproxen, a direct assay of anandamide amidase gave a half-maximal inhibitory concentration for ibuprofen of approximately 400 micromolar, and that potency was of the same order as required for inhibition of cyclooxygenase-2 in cell-free systems and as the peak plasma concentrations following a two times 200 milligram dose regimen, so following therapeutic doses the metabolism of anandamide may be affected.

    Ibuprofen → Metabolism of anandamide by amidohydrolase source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/ibuprofen-research/9060042.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2c89a26f3812060e97e7bb481126a90840282d64348fc8d4ae9d1dcc7f0a4543", "start_char": 0, "end_char": 1394, "text_sha256": "2c89a26f3812060e97e7bb481126a90840282d64348fc8d4ae9d1dcc7f0a4543"}
    experimental_model
    Rat cerebellar membrane preparations assayed by time-dependent loss of anandamide potency and by direct amidase assay
    exposure
    Ibuprofen compared against acetylsalicylic acid, sulindac, acetaminophen, ketoprofen and naproxen
    limitations
    The comparator set is what distinguishes this from a class effect: five other drugs failed. The concentration required is high, and the authors relate it to peak plasma levels rather than measuring them.
    nutrient_topic
    Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. · Ibuprofen
    organism
    Rat
    plain_language
    Ibuprofen, and not the other painkillers tested, slows the destruction of the body’s own cannabis-like signal.
    primary_references
    [ibu-p9060042] Ibuprofen inhibits the metabolism of the endogenous cannabimimetic agent anandamide. (1997). https://pubmed.ncbi.nlm.nih.gov/9060042/ DOI: 10.1111/j.1600-0773.1997.tb00291.x
    tissue_or_cell_type
    Cerebellar membranes

    Ibuprofen: the enantiomer that works, the one that was called inactive, the one-way chemistry that turns one into the other, and the targets that are not cyclooxygenase (2026-09-22) · lines 448–459

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Rat cerebellar membrane preparations assayed by time-dependent loss of anandamide potency and by direct amidase assay · source_derived_draft · unverified_draft

    ### ibu-blocks-anandamide-breakdown The time-dependent reduction in potency of anandamide toward inhibition of cannabinoid agonist binding in rat cerebellar membranes was blocked by ibuprofen but not by acetylsalicylic acid, sulindac, acetaminophen or to any significant extent by ketoprofen and naproxen, a direct assay of anandamide amidase gave a half-maximal inhibitory concentration for ibuprofen of approximately 400 micromolar, and that potency was of the same order as required for inhibition of cyclooxygenase-2 in cell-free systems and as the peak plasma concentrations following a two times 200 milligram dose regimen, so following therapeutic doses the metabolism of anandamide may be affected. Condition category: normal nutrient_topic: Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. plain_language: Ibuprofen, and not the other painkillers tested, slows the destruction of the body’s own cannabis-like signal. organism: Rat tissue_or_cell_type: Cerebellar membranes experimental_model: Rat cerebellar membrane preparations assayed by time-dependent loss of anandamide potency and by direct amidase assay limitations: The comparator set is what distinguishes this from a class effect: five other drugs failed. The concentration required is high, and the authors relate it to peak plasma levels rather than measuring them. exposure: Ibuprofen compared against acetylsalicylic acid, sulindac, acetaminophen, ketoprofen and naproxen evidence_span: {"source_cache": "artifacts/ibuprofen-research/9060042.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2c89a26f3812060e97e7bb481126a90840282d64348fc8d4ae9d1dcc7f0a4543", "start_char": 0, "end_char": 1394, "text_sha256": "2c89a26f3812060e97e7bb481126a90840282d64348fc8d4ae9d1dcc7f0a4543"} [ibu-p9060042] Ibuprofen inhibits the metabolism of the endogenous cannabimimetic agent anandamide. (1997). https://pubmed.ncbi.nlm.nih.gov/9060042/ DOI: 10.1111/j.1600-0773.1997.tb00291.x
    Complete structured claim and evidence

  2. Measurement of the inhibitory potency of non-steroidal anti-inflammatory drugs on cyclooxygenase isoforms is strongly influenced by variations in experimental conditions, the concentration of protein in the assay medium being particularly important because these drugs are highly protein bound in vivo so that assays based on human whole blood provide the most suitable test system, and of the drugs investigated only meloxicam showed selectivity for cyclooxygenase-2 at therapeutically relevant concentrations while standard drugs such as naproxen inhibited both isoforms to an equal degree.

    The human whole blood assay of cyclooxygenase activity → The ratio of cyclooxygenase-1 to cyclooxygenase-2 inhibitory potency source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/ibuprofen-research/9219317.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "d3edafe44ec9bf9e15505ffebb96add5467f8874fe8b585ce3878c473f250714", "start_char": 0, "end_char": 1162, "text_sha256": "d3edafe44ec9bf9e15505ffebb96add5467f8874fe8b585ce3878c473f250714"}
    experimental_model
    Comparison of cyclooxygenase inhibitory potency across assay systems, using the human whole blood assay
    exposure
    Standard non-steroidal anti-inflammatory drugs compared at therapeutically relevant concentrations
    limitations
    Argues that the whole blood assay is the appropriate test because these drugs are highly protein bound. It reports conclusions about the class, with naproxen named rather than ibuprofen.
    nutrient_topic
    Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. · Ibuprofen
    organism
    Human
    plain_language
    Measured in blood rather than in a tube of enzyme, the ordinary anti-inflammatories hit both enzymes about equally.
    primary_references
    [ibu-p9219317] Differentiating among nonsteroidal antiinflammatory drugs by pharmacokinetic and pharmacodynamic profiles. (1997). https://pubmed.ncbi.nlm.nih.gov/9219317/ DOI: 10.1016/s0049-0172(97)80050-9
    tissue_or_cell_type
    Whole blood

    Ibuprofen: the enantiomer that works, the one that was called inactive, the one-way chemistry that turns one into the other, and the targets that are not cyclooxygenase (2026-09-22) · lines 344–355

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Comparison of cyclooxygenase inhibitory potency across assay systems, using the human whole blood assay · source_derived_draft · unverified_draft

    ### ibu-no-selectivity-in-whole-blood Measurement of the inhibitory potency of non-steroidal anti-inflammatory drugs on cyclooxygenase isoforms is strongly influenced by variations in experimental conditions, the concentration of protein in the assay medium being particularly important because these drugs are highly protein bound in vivo so that assays based on human whole blood provide the most suitable test system, and of the drugs investigated only meloxicam showed selectivity for cyclooxygenase-2 at therapeutically relevant concentrations while standard drugs such as naproxen inhibited both isoforms to an equal degree. Condition category: normal nutrient_topic: Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. plain_language: Measured in blood rather than in a tube of enzyme, the ordinary anti-inflammatories hit both enzymes about equally. organism: Human tissue_or_cell_type: Whole blood experimental_model: Comparison of cyclooxygenase inhibitory potency across assay systems, using the human whole blood assay limitations: Argues that the whole blood assay is the appropriate test because these drugs are highly protein bound. It reports conclusions about the class, with naproxen named rather than ibuprofen. exposure: Standard non-steroidal anti-inflammatory drugs compared at therapeutically relevant concentrations evidence_span: {"source_cache": "artifacts/ibuprofen-research/9219317.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "d3edafe44ec9bf9e15505ffebb96add5467f8874fe8b585ce3878c473f250714", "start_char": 0, "end_char": 1162, "text_sha256": "d3edafe44ec9bf9e15505ffebb96add5467f8874fe8b585ce3878c473f250714"} [ibu-p9219317] Differentiating among nonsteroidal antiinflammatory drugs by pharmacokinetic and pharmacodynamic profiles. (1997). https://pubmed.ncbi.nlm.nih.gov/9219317/ DOI: 10.1016/s0049-0172(97)80050-9
    Complete structured claim and evidence

  3. The S(+) isomer of ibuprofen was 32-, 41- and 96-fold more potent than the R(-) isomer for inhibition of prostaglandin endoperoxide H synthase-1 activity, human platelet aggregation and serotonin secretion respectively, while on prostaglandin endoperoxide H synthase-2 the ibuprofen isomers showed no selectivity, and indomethacin, S(+)-ibuprofen and S(+)-naproxen were 6-, 27- and 5-fold more potent as inhibitors of synthase-1 than of synthase-2.

    S(+)-ibuprofen → R(-)-ibuprofen source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/ibuprofen-research/11755111.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1dd77f4a1eebd7777285c424b1731f4744d0fa593e62cfbde0a92dbb6242b239", "start_char": 0, "end_char": 2074, "text_sha256": "1dd77f4a1eebd7777285c424b1731f4744d0fa593e62cfbde0a92dbb6242b239"}
    experimental_model
    Reporter and enzyme assays comparing ibuprofen isomers against naproxen and indomethacin across four readouts
    exposure
    S(+)- and R(-)-ibuprofen compared directly on cyclooxygenase-1 and -2, platelet function and nuclear receptor activation
    limitations
    The only record here that measures both enantiomers on the same panel, which is what makes the fold-differences meaningful. Several different assay systems are combined.
    nutrient_topic
    Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. · Ibuprofen
    organism
    Rat, human and sheep systems
    plain_language
    At the first enzyme one hand is thirty to ninety times stronger; at the second enzyme the two hands are indistinguishable.
    primary_references
    [ibu-p11755111] Activation of peroxisome proliferator-activated receptor isoforms and inhibition of prostaglandin H(2) synthases by ibuprofen, naproxen, and indomethacin. (2001). https://pubmed.ncbi.nlm.nih.gov/11755111/ DOI: 10.1016/s0006-2952(01)00822-x
    tissue_or_cell_type
    Transfected cells, hepatoma cells, platelets and purified enzyme

    Ibuprofen: the enantiomer that works, the one that was called inactive, the one-way chemistry that turns one into the other, and the targets that are not cyclooxygenase (2026-09-22) · lines 318–329

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Reporter and enzyme assays comparing ibuprofen isomers against naproxen and indomethacin across four readouts · source_derived_draft · unverified_draft

    ### ibu-thirty-two-fold-at-cox1 The S(+) isomer of ibuprofen was 32-, 41- and 96-fold more potent than the R(-) isomer for inhibition of prostaglandin endoperoxide H synthase-1 activity, human platelet aggregation and serotonin secretion respectively, while on prostaglandin endoperoxide H synthase-2 the ibuprofen isomers showed no selectivity, and indomethacin, S(+)-ibuprofen and S(+)-naproxen were 6-, 27- and 5-fold more potent as inhibitors of synthase-1 than of synthase-2. Condition category: normal nutrient_topic: Ibuprofen research collection; topical membership is not evidence of a direct clinical effect, and the racemate is recorded separately from each of its two enantiomers. plain_language: At the first enzyme one hand is thirty to ninety times stronger; at the second enzyme the two hands are indistinguishable. organism: Rat, human and sheep systems tissue_or_cell_type: Transfected cells, hepatoma cells, platelets and purified enzyme experimental_model: Reporter and enzyme assays comparing ibuprofen isomers against naproxen and indomethacin across four readouts limitations: The only record here that measures both enantiomers on the same panel, which is what makes the fold-differences meaningful. Several different assay systems are combined. exposure: S(+)- and R(-)-ibuprofen compared directly on cyclooxygenase-1 and -2, platelet function and nuclear receptor activation evidence_span: {"source_cache": "artifacts/ibuprofen-research/11755111.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1dd77f4a1eebd7777285c424b1731f4744d0fa593e62cfbde0a92dbb6242b239", "start_char": 0, "end_char": 2074, "text_sha256": "1dd77f4a1eebd7777285c424b1731f4744d0fa593e62cfbde0a92dbb6242b239"} [ibu-p11755111] Activation of peroxisome proliferator-activated receptor isoforms and inhibition of prostaglandin H(2) synthases by ibuprofen, naproxen, and indomethacin. (2001). https://pubmed.ncbi.nlm.nih.gov/11755111/ DOI: 10.1016/s0006-2952(01)00822-x
    Complete structured claim and evidence

  4. Prostanoid production by rat aorta, heart, lung and whole blood was inhibited by all drugs tested with the order of potency SC560 greater than naproxen greater than acetaminophen greater than or equal to rofecoxib while in brain and cerebellum no differences among drug potencies were found, Western blotting using a commercially available antibody raised against canine COX-3 failed to detect any immunoreactive proteins, and the authors conclude that cyclooxygenase-1 and -2 are the functional forms present in the rat tissues tested, that acetaminophen is not a selective inhibitor of cyclooxygenase activities in the central nervous system, and that expression of an active cyclooxygenase protein from COX-3 messenger RNA in the rat is apparently impossible.

    COX-3 / COX-1b, a cyclooxygenase-1 transcript retaining intron 1 → Antinociception in thermal, mechanical and chemical pain tests source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/paracetamol-research/15148345.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6ca43f39a9bb4cbc398f4f7f6e3401854f6c100b72fb7fdf952ee49486438d3c", "start_char": 0, "end_char": 1940, "text_sha256": "6ca43f39a9bb4cbc398f4f7f6e3401854f6c100b72fb7fdf952ee49486438d3c"}
    experimental_model
    Comparison of acetaminophen, rofecoxib, naproxen and SC560 across rat aorta, heart, lung, brain, cerebellum and whole blood
    exposure
    Four drugs of differing isoform selectivity, with transcript and protein detection including an anti-canine-COX-3 antibody
    limitations
    Tests the proposal functionally across tissues and looks for the protein directly. A rat study, and a negative Western blot is weaker evidence than a positive 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
    Rat
    plain_language
    Nobody could find the protein, and in brain the drug showed no special selectivity at all.
    primary_references
    [apap-p15148345] Cyclooxygenases 1, 2, and 3 and the production of prostaglandin I2: investigating the activities of acetaminophen and cyclooxygenase-2-selective inhibitors in rat tissues. (2004). https://pubmed.ncbi.nlm.nih.gov/15148345/ DOI: 10.1124/jpet.103.063875
    tissue_or_cell_type
    Multiple tissues

    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 233–244

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Comparison of acetaminophen, rofecoxib, naproxen and SC560 across rat aorta, heart, lung, brain, cerebellum and whole blood · source_derived_draft · unverified_draft

    ### apap-no-cox3-protein-found Prostanoid production by rat aorta, heart, lung and whole blood was inhibited by all drugs tested with the order of potency SC560 greater than naproxen greater than acetaminophen greater than or equal to rofecoxib while in brain and cerebellum no differences among drug potencies were found, Western blotting using a commercially available antibody raised against canine COX-3 failed to detect any immunoreactive proteins, and the authors conclude that cyclooxygenase-1 and -2 are the functional forms present in the rat tissues tested, that acetaminophen is not a selective inhibitor of cyclooxygenase activities in the central nervous system, and that expression of an active cyclooxygenase protein from COX-3 messenger RNA in the rat is apparently impossible. 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: Nobody could find the protein, and in brain the drug showed no special selectivity at all. organism: Rat tissue_or_cell_type: Multiple tissues experimental_model: Comparison of acetaminophen, rofecoxib, naproxen and SC560 across rat aorta, heart, lung, brain, cerebellum and whole blood limitations: Tests the proposal functionally across tissues and looks for the protein directly. A rat study, and a negative Western blot is weaker evidence than a positive one. exposure: Four drugs of differing isoform selectivity, with transcript and protein detection including an anti-canine-COX-3 antibody evidence_span: {"source_cache": "artifacts/paracetamol-research/15148345.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6ca43f39a9bb4cbc398f4f7f6e3401854f6c100b72fb7fdf952ee49486438d3c", "start_char": 0, "end_char": 1940, "text_sha256": "6ca43f39a9bb4cbc398f4f7f6e3401854f6c100b72fb7fdf952ee49486438d3c"} [apap-p15148345] Cyclooxygenases 1, 2, and 3 and the production of prostaglandin I2: investigating the activities of acetaminophen and cyclooxygenase-2-selective inhibitors in rat tissues. (2004). https://pubmed.ncbi.nlm.nih.gov/15148345/ DOI: 10.1124/jpet.103.063875
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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