This page shows what was measured, who it was measured in, and what that does not settle.
What Naproxen does in the body
Pain, fever and inflammation, especially where it needs to last
Naproxen blocks the two enzymes that turn a fatty acid released by injured tissue into prostaglandins — the messengers that make nerve endings fire more easily, blood vessels leak and the body raise its temperature. What separates it from ibuprofen is not the mechanism but the clock: naproxen stays in the blood for twelve to seventeen hours instead of two, so one dose covers most of a day. That long occupancy also means it holds platelets down for longer, which looks like heart protection and is in fact a bleeding risk, and its own label warns it is not a replacement for the aspirin that actually protects hearts.
What happened in people
Number needed to treat 2.7 (95% CI 2.3 to 3.2) for at least 50% pain relief over four to six hours from a single 500/550 mg dose
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
That naproxen carries a lower cardiovascular thrombotic risk than other NSAIDs — an FDA advisory committee voted 16 to 9 that the data do not support it and the label does not say it
Where it acts
The cyclooxygenase channel of COX-1 and COX-2 in inflamed tissue, gastric mucosa, kidney and platelets — occupied for far longer than by any other common NSAID because of a 12-to-17-hour half-life
Kind of result
Symptoms and quality of life
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
Its recorded molecular formula is C14H13NaO3, weighing 252.23.
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 150 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Stand-in result
A stand-in result is a number measured because the real result takes too long.
A picture of it, and where the picture fails
It is like judging a journey by the speedometer rather than by arriving.
Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.
What people get wrong. A stand-in result is often reported as the result itself.
A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
Pathway
A pathway is a chain of steps inside a cell, each one setting off the next.
A picture of it, and where the picture fails
A pathway is like a row of dominoes.
Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.
What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.
An ordered series of molecular interactions producing a defined cellular change.
What happened in people◇Read from sources, not yet reviewed
What was measured, goal by goal
One row for each goal a registered study measured something for. One column for each kind of thing that could be measured.
Registered studies list 40 outcome measures that RNAWiki could read. A registered study says what someone planned to measure. It does not say what they found. 0 of the matched studies tested this substance, and 0 posted a result.
There is no single score. A strong test result and a weak life result are different facts.
Goals down the side, kinds of measurement across the top. Each cell says what kind of thing was registered, not what was found.
Goal
Life outcome
What a body can do
How a person feels
A test result
A step in the body
Harms
How long
Who was studied
Pain
∅Nothing in the sources checkedNo registered study lists a life outcome for this goal.
∅Nothing in the sources checkedNo registered study lists a performance measure for this goal.
…Waiting for a reviewer8 registered symptom measure.
∅Nothing in the sources checkedNo registered study lists a test result for this goal.
∅Nothing in the sources checkedNo registered study lists a body-step measure for this goal.
—Not recordedHarms were not a registered measure for this goal.
—Not recordedNo finished study window is recorded.
…Waiting for a reviewerWho was studied is listed further down the page.
Which registered measures put each goal on this table
Pain
s assessment of arthritis pain; s assessment of arthritis pain using a visual analogue scale; pressure pain threshold area under the curve; visual analogue scale of pain; pain intensity; pain assessed by visual analogue scale; pain vas; vas pain scale
Sorted by fixed word lists, version v1. A name the rules do not recognise stays unsorted rather than moving to the nearest column.
What each mark on this table means
∅ Nothing in the sources checked
No registered study lists a life outcome for this goal.
… Waiting for a reviewer
8 registered symptom measure.
— Not recorded
Harms were not a registered measure for this goal.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Antiplatelet Trialists Collaboration composite of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, adjudicated
Naproxen 2.5%, celecoxib 2.3%, ibuprofen 2.7% in the intention-to-treat analysis; hazard ratio celecoxib against naproxen 0.93 (95% CI 0.76 to 1.13), p<0.001 for non-inferiority. Gastrointestinal events significantly lower on celecoxib than naproxen (p=0.01); renal events not significantly different (p=0.19)
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Mean naproxen dose achieved was 852±103 mg daily, below the 1,000 mg used in the CNT high-dose analyses. 68.8% of patients stopped study drug and 27.4% discontinued follow-up entirely.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
Cardiovascular or cerebrovascular composite three-year incidence 8.25% on naproxen against 5.68% on placebo, hazard ratio 1.63 (95% CI 1.04 to 2.55). Antihypertensive initiation 45.0% against 34.1%, hazard ratio 1.40 (1.12 to 1.75). No improvement in cognitive function; weak evidence of a detrimental effect of naproxen on the global summary score (-0.05 SD, p=0.02)
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The trial was suspended in December 2004 after the celecoxib arm of a different trial reported cardiovascular harm, so follow-up ranged from 1 to 46 months and the cardiovascular analysis was unplanned. It is the only randomised placebo-controlled cardiovascular signal that exists for naproxen at an over-the-counter dose, and it points the opposite way from the drug’s reputation.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily
Interval reported. 95% CI 1
Written into the record, not signed off as a reviewed claim.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
Proportion of participants with at least 50% pain relief over four to six hours after a single oral dose
✓ The study showed what it set out to show
Who was studied
Cochrane CD004234 — pooled single-dose postoperative pain trials
How many people
1509
Study design
Systematic review of 15 randomised, double-blind, placebo-controlled trials
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Number needed to treat 2.7 (95% CI 2.3 to 3.2) at 500/550 mg across nine studies and 784 participants; median time to rescue medication 8.9 hours against 2.0 hours on placebo
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. No dose response was demonstrated over the range 200/220 mg to 500/550 mg, on limited data at the lower doses. The models are predominantly dental extraction and the horizon is six hours.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily
Interval reported. 95% CI 2
Written into the record, not signed off as a reviewed claim.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
RNAWiki holds 3 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
■Symptoms and quality of lifeEvidence recorded. Pain, tiredness, mood, sleep, as the person rated it.8 registered measures of this kind.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.7 registered measures of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
■AnimalsEvidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in Rat. A result in animals says what to test next. It does not say what happens in people.
■Cells in a dishEvidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Where a source records it acting
Joints: In rheumatoid arthritis, improvement was demonstrated by a reduction in joint swelling and a reduction in duration of morning stiffness
US prescribing information · 000155a8-709c-44e5-a75f-cd890f3a7caf · read 2026-08-27
Start
Naproxen
What a person takes: Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily.
The measurement behind this step
Rapidly and completely absorbed with an in vivo bioavailability of about 95%; the different dosage forms are bioequivalent for total exposure but differ in the pattern of absorption, which is why the sodium salt is used where speed of onset matters. Plasma protein binding exceeds 99% and elimination half-life is twelve to seventeen hours — several times longer than ibuprofen, and the source of both its convenience and its prolonged platelet and gastric effects.
Getting in
One hand only, set in the factory
Most drugs in this family are sold as a mixture of two mirror-image forms and the body sorts it out. Naproxen is sold as the active form alone, because the synthesis sets it.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
The single S-(+) enantiomer of 2-(6-methoxynaphthalen-2-yl)propanoic acid. Absolute bioavailability about 95%; plasma protein binding above 99%. Naproxen sodium is the same molecule as a salt for faster dissolution — 220 mg of the sodium salt carries 200 mg of naproxen.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
It blocks the same channel — and then does not leave for half a day
Naproxen sits in the enzyme’s tunnel and blocks it, like ibuprofen. The difference is the clock: it clears in twelve to seventeen hours rather than two, so one dose covers most of a day.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Reversible competitive inhibition of the cyclooxygenase site of PTGS1 and PTGS2, without selectivity between them. The elimination half-life of twelve to seventeen hours is the longest among widely used non-selective NSAIDs and is the reason for twice-daily dosing and for a prolonged platelet effect.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
Less prostaglandin means nerve endings need a stronger stimulus before they fire, and inflamed tissue leaks less fluid. In pooled trials, one 500 mg dose halved pain in enough patients to give a number needed to treat of 2.7.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The label states that prostaglandins sensitise afferent nerves and potentiate the action of bradykinin in inducing pain, and are mediators of inflammation, and that naproxen’s mode of action may be due to a decrease of prostaglandins in peripheral tissues. Cochrane CD004234: NNT 2.7 (95% CI 2.3 to 3.2) for at least 50% pain relief over four to six hours at 500/550 mg, median time to rescue 8.9 hours against 2.0 on placebo.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
The stomach pays the most of any drug in the class
The same enzyme keeps the stomach lining protected. Because naproxen occupies it for so much longer than ibuprofen does, the lining gets less recovery time — and naproxen has the highest measured rate of serious gastric bleeding of the common anti-inflammatories.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Upper gastrointestinal complications rate ratio 4.22 (95% CI 2.71 to 6.56) against placebo, the highest in the CNT analysis of 280 placebo-controlled trials. In PRECISION, gastrointestinal events were significantly lower on celecoxib than on naproxen (p=0.01).
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
Platelets stay suppressed — which is not the same as heart protection
Long occupancy of the platelet enzyme looks like what aspirin does, and it is not. Naproxen lets go again; aspirin does not. Its own label says naproxen is not a substitute for low-dose aspirin.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Reversible platelet COX-1 inhibition producing incomplete thromboxane suppression that recovers as drug clears, against aspirin’s covalent acetylation of Ser-529 which the anucleate platelet cannot repair. Label section 12.2 documents naproxen reducing aspirin’s thromboxane inhibition from 98.7% to as low as 84.3%, worst during naproxen washout.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
Measured: no significant increase in major vascular events in pooled randomised trials, and a 63% higher cardiovascular event rate in a randomised prevention trial in the elderly. Voted down: putting a lower-cardiovascular-risk claim in the label, 16 to 9.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
CNT: major vascular events rate ratio 0.93 (95% CI 0.69 to 1.27), not significant; heart failure roughly doubled as with every NSAID. ADAPT: cardiovascular and cerebrovascular composite hazard ratio 1.63 (1.04 to 2.55) against placebo in 2,528 participants. FDA joint advisory committee, February 2014: 16 to 9 that the data do not support a lower cardiovascular thrombotic risk for naproxen.
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What it would be like to take◇Read from sources, not yet reviewed
Felt, measured, or meaningful
Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.
Felt
Things a person could notice without a test.
s assessment of arthritis pain
s assessment of arthritis pain using a visual analogue scale
pressure pain threshold area under the curve
visual analogue scale of pain
pain intensity
pain assessed by visual analogue scale
pain vas
vas pain scale
Measured
Things only a test, a scale or a device shows.
systolic blood pressure at week 6/final visit
observed maximum concentration
time of maximum concentration
serum c reactive protein at day 7
cmax in plasma of dph hcl
pk profile of lesinurad from plasma and urine
serum urate 5 0 / at month 3
Meaningful
Things that change how a life goes, not only a number.
No registered study measured anything of this kind.
A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.
Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.
Measured, but not felt. A number moves. The person notices nothing. Both can be true.
Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.
Matters, but takes years. The result that counts may take longer than anyone would keep watching.
Names that fit none of the three (25)
numerical rating scale
womac
monitored for long term safety of pn 400
acr 20 criteria responder
acr pediatric 30
pk parameters
pharmacokinetics parameters
pharmacokinetics
study compound s biochemical selectivity for cox 2
bleeding and spotting days
treatment success event rates in each group
perimetric mean deviation
bioequivalence based on cmax and auc parameters
safety assessments
safety
part a number of intolerance events
adverse events as a measure of safety and tolerability
clinical laboratory tests
apparent terminal rate constant apparent terminal half life
apparent systemic clearance after extravascular dosing
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
What it would be like to take◇Read from sources, not yet reviewed
How long anything takes
Nine different lengths of time that get confused with each other. None of them is worked out from another.
Before anything is noticed.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before a test result moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before performance moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
How long the result was watched.No finished study window is recorded for a study that tested this substance.
How long people took it.How long people actually took it is not stored. The study window is not the same thing.
How long people were followed.Follow-up length is not stored separately. It is never read off the study window, which would be a different thing.
How fast the body clears it. 12 to 17 hours hours
Read from the label, which states: “The plasma half-life of the naproxen anion in humans ranges from 12 to 17 hours.”
How long effects linger.RNAWiki does not store this separately, and never works it out from another figure on this page.
Beyond the studies. Nothing is recorded about the long term.
The longest finished study sets the edge of what anyone measured.
A study window is not how long people took it, and neither is how long they were followed. Where RNAWiki holds only one of the three, it shows one.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Adults and children with inflammatory arthritis or pain, and very large numbers of people buying naproxen sodium over the counter. Not people in the setting of coronary artery bypass graft surgery, and not people with aspirin-sensitive asthma.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness in pediatric patients below the age of 2 years have not been established.”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
On older people, the label states: “The hepatic and renal tolerability of long-term naproxen administration was studied in two double-blind clinical trials involving 586 patients.”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Use of NSAIDs, including naproxen sodium, can cause premature closure of the fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment.”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
On people who are breastfeeding, the label states: “8.3 Females and Males of Reproductive Potential Infertility Females Based on the mechanism of action, the use of prostaglandin-mediated NSAIDs, including naproxen sodium may delay or prevent rupture of ovarian follicles, which has been associated with reversible infertility in some women.”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
On people with reduced liver function, the label states: “Caution is advised when high doses are required and some adjustment of dosage may be required in these patients.”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
On people with reduced kidney function, the label states: “Naproxen-containing products are not recommended for use in patients with moderate to severe and severe renal impairment (creatinine clearance <30 mL/min) [see Warnings and Precautions (5.6) , Clinical Pharmacology (12.3) ].”
US prescribing information · 37b264f9-b46d-4635-8fab-246b1e08b653 · read 2026-08-30
Where the result stopped carrying
ADAPT: naproxen did not prevent Alzheimer’s dementia, showed weak evidence of cognitive harm, and had a higher cardiovascular event rate than placebo
The gastrointestinal record is the worst of the common NSAIDs on randomised data
The aspirin interaction persists after naproxen is stopped and had not normalised by day 13 in the label’s study
No dose response could be demonstrated between the over-the-counter and prescription strengths in pooled single-dose trials
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied for a different goal
The studies measured something else entirely.
On this record: Some registered studies measured things that match no goal on this page.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (10)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S3, S6.
No source is stored against this line.
What is in the pack
Rapidly and completely absorbed with an in vivo bioavailability of about 95%; the different dosage forms are bioequivalent for total exposure but differ in the pattern of absorption, which is why the sodium salt is used where speed of onset matters.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: Plasma protein binding exceeds 99% and elimination half-life is twelve to seventeen hours — several times longer than ibuprofen, and the source of both its convenience and its prolonged platelet and gastric effects.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Boxed warning for cardiovascular thrombotic events including fatal myocardial infarction and stroke, and for gastrointestinal bleeding, ulceration and perforation which can occur at any time and without warning symptoms. Contraindicated in the setting of coronary artery bypass graft surgery. Synergistic bleeding risk with warfarin, and increased bleeding risk with SSRIs and SNRIs. Interferes with the antiplatelet effect of low-dose aspirin, most markedly during naproxen washout, and is not a substitute for it. May diminish the antihypertensive effect of ACE inhibitors, ARBs and beta-blockers, and co-administration with an ACE inhibitor or ARB in elderly, volume-depleted or renally impaired patients may cause deterioration of renal function including acute renal failure. Raises serum digoxin and lithium concentrations.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analys… · a recorded source, not a stored snapshot
These are reports people sent to a regulator. They do not show the medicine caused the reaction.
Nobody counted how many people took the medicine and reported nothing.
The same event can be reported more than once, and many reports are incomplete.
News coverage, lawsuits and new warnings change how often people report.
A count is not a rate and not a risk.
Naproxen appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 6316 reaction mentions were counted. One report can name several reactions.
open-targets-adr · recorded 2026-06-24 · a recorded source, not a stored snapshot
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Oral tablets, delayed-release tablets, controlled-release tablets and oral suspension, as naproxen or as the more rapidly dissolving naproxen sodium; taken twice daily
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
A recorded note compares this form with the others that are sold. It is kept below, word for word.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
The recorded note, unchanged: Plasma protein binding exceeds 99% and elimination half-life is twelve to seventeen hours — several times longer than ibuprofen, and the source of both its convenience and its prolonged platelet and gastric effects.
No source is stored against this line.
What is recorded as being sold
578 products list this as an active ingredient in the United States drug directory. 515 of them contain it and nothing else.
FDA National Drug Code directory · 72036-145 · read 2026-08-29
They are sold as capsule, capsule, liquid filled, powder, suspension, tablet and tablet, coated, taken oral.
FDA National Drug Code directory · 72036-145 · read 2026-08-29
The regulator's established pharmacologic class for it is anti-inflammatory agents, cyclooxygenase inhibitors [moa] and non-steroidal [cs].
FDA National Drug Code directory · 72036-145 · read 2026-08-29
452 published labels name it as an active ingredient. 396 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 3d01220c-c5ec-4604-8cef-9ecb807ccd53 · read 2026-08-29
Those labels are classed as human otc drug and human prescription drug.
US prescribing information · 3d01220c-c5ec-4604-8cef-9ecb807ccd53 · read 2026-08-29
6 marketed supplement labels list this ingredient, classed as other combinations and vitamin.
Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Naproxen is tablets (naproxen); film-coated tablets (naproxen sodium) at Naproxen Tablets, USP: 250 mg, 375 mg and 500 mg; Naproxen Sodium Tablets, USP: 275 mg and 550 mg, recorded as prescription product; fda label in effect 2026-01-29 in the United States.
US prescribing information · 000155a8-709c-44e5-a75f-cd890f3a7caf · read 2026-08-27
Recorded price in US: 0.04377–0.23301 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 69 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Recorded price in US: 0.11732–0.19124 USD per one millilitre, across 5 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Naproxen studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That naproxen carries a lower cardiovascular thrombotic risk than other NSAIDs — an FDA advisory committee voted 16 to 9 that the data do not support it and the label does not say it
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That naproxen can stand in for cardioprotective aspirin, which the label explicitly denies
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That a non-significant rate ratio of 0.93 is a demonstration of cardiovascular safety rather than an absence of a demonstrated increase
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the vascular composite settles the cardiac question, when heart failure risk was roughly doubled by every NSAID regimen studied including naproxen
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Naproxen are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
An FDA advisory committee voted 16 to 9 against the claim that naproxen is safer for the heart
In plain words
The belief that naproxen is the heart-friendly NSAID is the single most widespread thing said about it. In February 2014 the FDA convened its arthritis and drug safety committees to decide whether the label should say so. They voted 16 to 9 that the data do not support it.
What was measured
That naproxen carries a lower cardiovascular thrombotic risk than other NSAIDs — an inference from indirect comparisons that a regulator’s advisory committee examined and declined to place in the label
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The committee’s objection was about the shape of the evidence, not the direction of it. Naproxen’s apparent cardiovascular advantage comes overwhelmingly from trials in which naproxen was the comparator arm for a coxib, so the finding is a difference between two drugs rather than a measurement of naproxen against placebo — and dissenters noted that preferential labelling might inadvertently cause harm by increasing use and with it naproxen’s gastrointestinal risk, which is the highest of the class. The published summary of the meeting records the vote as 16 to nine that the data do not support naproxen’s lower cardiovascular thrombotic risk as compared with other NSAIDs, and concludes that there is insufficient evidence to conclude from a population perspective that there are differences between the major marketed NSAIDs in regard to their potential for cardiovascular events. The label was not changed. Every prescription naproxen product still carries the same boxed cardiovascular thrombotic warning as every other NSAID.
Written into the record, not signed off as a reviewed claim
The one randomised result the reputation is built on, stated exactly
In plain words
In the biggest pooled analysis of randomised NSAID trials ever assembled, naproxen was the only traditional anti-inflammatory that did not significantly increase major vascular events. That result is real, and it is a non-significant finding, not a demonstration of safety.
What was measured
Rate ratio for major vascular events, major coronary events, vascular death and heart failure, by molecule, against placebo
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The CNT Collaboration pooled individual participant data from 280 trials of an NSAID against placebo (124,513 participants, 68,342 person-years) and 474 trials of one NSAID against another (229,296 participants). Major vascular events — non-fatal myocardial infarction, non-fatal stroke or vascular death — were increased by about a third by a coxib (rate ratio 1.37, 95% CI 1.14 to 1.66) and by diclofenac (1.41, 1.12 to 1.78). For naproxen the rate ratio was 0.93 (0.69 to 1.27), which is not a significant increase; vascular death alone was 1.08 (0.48 to 2.47). Two things must be said alongside it. The confidence interval reaches 1.27, so a 27% increase is not excluded. And heart failure risk was roughly doubled by all NSAID regimens in the analysis, naproxen included — the vascular composite is not the only cardiac endpoint.
Written into the record, not signed off as a reviewed claim
Naproxen has the worst upper gastrointestinal record of the common NSAIDs
In plain words
The same analysis that gave naproxen its heart reputation gave it the highest rate of serious stomach and duodenal complications of every drug it examined — a 4.22-fold increase, worse than ibuprofen, worse than diclofenac, worse than the coxibs.
What was measured
Rate ratio for upper gastrointestinal perforation, obstruction or bleed against placebo, by molecule
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Upper gastrointestinal complications — perforation, obstruction or bleed — rose against placebo by a rate ratio of 4.22 (95% CI 2.71 to 6.56, p<0.0001) for naproxen, 3.97 (2.22 to 7.10) for ibuprofen, 1.89 (1.16 to 3.09) for diclofenac and 1.81 (1.17 to 2.81) for coxibs. In the head-to-head PRECISION trial, gastrointestinal events were significantly lower with celecoxib than with naproxen (p=0.01). This is the trade being made whenever naproxen is chosen for its cardiovascular profile, and it is rarely stated in those terms: the drug with the least measured vascular signal has the most measured bleeding.
Written into the record, not signed off as a reviewed claim
ADAPT: randomised to naproxen, more cardiovascular events, and no protection against dementia
In plain words
A prevention trial randomised 2,528 people over seventy to naproxen, celecoxib or placebo to see whether anti-inflammatories prevent Alzheimer’s. They do not. And the naproxen group had a 63% higher rate of cardiovascular and cerebrovascular events than placebo.
What was measured
Three-year incidence of a cardiovascular and cerebrovascular composite, and initiation of antihypertensive treatment, in 2,528 randomised elderly participants
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
ADAPT randomised 2,528 participants aged 70 and over with a family history of Alzheimer’s dementia to celecoxib 200 mg twice daily, naproxen sodium 220 mg twice daily or placebo, and was suspended in December 2004 after the APC trial reported cardiovascular harm with celecoxib. The composite of cardiovascular or cerebrovascular death, myocardial infarction, stroke, congestive heart failure or transient ischaemic attack occurred in 28/717 on celecoxib (three-year incidence 5.54%), 40/713 on naproxen (8.25%) and 37/1,070 on placebo (5.68%) — hazard ratio 1.10 (95% CI 0.67 to 1.79) for celecoxib and 1.63 (1.04 to 2.55) for naproxen. Antihypertensive treatment was started in 45.0% on naproxen against 34.1% on placebo, hazard ratio 1.40 (1.12 to 1.75). The trial’s own conclusion was that the naproxen data, although not definitive, are suggestive of increased cardiovascular and cerebrovascular risk. On the question it was designed to answer, neither drug improved cognitive function, and there was weak evidence of a detrimental effect of naproxen on the global summary score (-0.05 SD, p=0.02); the ten-year follow-up study confirmed no protection.
Written into the record, not signed off as a reviewed claim
The over-the-counter dose was never shown to be weaker than the prescription dose
In plain words
The pharmacy sells 220 mg and the prescription pad writes 500 mg. In the pooled single-dose trials, no dose-response could be demonstrated anywhere between them — though the data at the low end were thin.
What was measured
Number needed to treat for at least 50% pain relief over four to six hours, and dose-response across 200/220 mg to 500/550 mg
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The Cochrane review of single-dose oral naproxen and naproxen sodium for acute postoperative pain included 15 studies in 1,509 participants. In the nine studies using 500 or 550 mg (784 participants) the number needed to treat for at least 50% pain relief over four to six hours was 2.7 (95% CI 2.3 to 3.2), with median time to rescue medication of 8.9 hours against 2.0 hours on placebo. The review states that no dose response was demonstrated over the range 200/220 mg to 500/550 mg, and immediately qualifies it: limited data were identified at the lower doses. That is an absence of evidence for a difference and not evidence of no difference — but it does mean that the more-than-doubled dose separating the over-the-counter product from the prescription one has never been shown to buy more analgesia in this setting, while it does buy proportionally more exposure to the gastrointestinal and renal effects.
Written into the record, not signed off as a reviewed claim
It interferes with aspirin too — and the interference is worst after you stop it
In plain words
Naproxen blocks aspirin from reaching its target in platelets, the same way ibuprofen does. The unexpected part, measured in the study printed in naproxen’s own label, is that the worst interference came in the days after naproxen was stopped.
What was measured
Percentage serum thromboxane B2 inhibition at 24 hours with aspirin alone against aspirin plus naproxen, during dosing and through washout
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Section 12.2 of the naproxen label reports a healthy-volunteer study: ten days of naproxen 220 mg once daily with 81 mg immediate-release aspirin reduced serum thromboxane B2 inhibition at 24 hours after the day-10 dose from 98.7% with aspirin alone to 93.1%. The interaction was greater when naproxen was given 30 minutes before aspirin (98.7% against 87.7%) and minimal in the reverse order (95.4%). On naproxen 220 mg twice daily the interaction was minimal during dosing (95.7%) but far more prominent after naproxen was discontinued on day 11 (84.3%), and had still not normalised by day 13 (90.7%). The label draws the conclusion explicitly: because there may be an increased risk of cardiovascular events following discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, a patient on cardioprotective aspirin who needs intermittent analgesia should be considered for a non-interfering NSAID or a non-NSAID. The same section states that naproxen is not a substitute for low dose aspirin for cardiovascular protection.
Source
Naproxen tablets United States prescribing information, sections 7 and 12.2 (openFDA label endpoint, ANDA 078250)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
How many documents were read
387 documents were read for this substance.
RNAWiki source record
149 of them state the same bioavailability, and they agree.
RNAWiki source record
149 of them state the same volumeOfDistribution, and they agree.
RNAWiki source record
Where else this substance is registered
FDA substance identifier (UNII)
57Y76R9ATQ
CAS registry number
22204-53-1
PubChem compound
156391
RxNorm concept
7258
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Written into the record, not signed off.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✓ Passed
Safety mode resolved
Suppression classes recorded: S3, S6.
✓ Passed
Canonical metadata present
slug and display name present
What is missing or unclear◇Read from sources, not yet reviewed
How this medicine reached us
Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.
What the approval register records
109 approved applications cover products containing this substance. The earliest was NDA017581, approved 19760311 to ATNAHS PHARMA US.
This order is fixed in code and does not count clicks or time on the page.
What is not here
3 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A long-acting non-selective cyclooxygenase inhibitor that relieves at least half of postoperative pain in enough patients to give a number needed to treat of 2.7, and is widely believed to be the heart-safe NSAID on the strength of a single non-significant randomised result — while the same meta-analysis gave it the highest upper gastrointestinal complication rate of the class at 4.22, a randomised prevention trial found a cardiovascular hazard ratio of 1.63, and its own label states it is not a substitute for low-dose aspirin.
Recorded evidence blocks (12)
Q2
What did Naproxen's largest trial (24081 people) and its longest (12 years) measure?
24081 people in Naproxen's largest registered study, 12 years in its longest registered window, measuring Change From Baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function Subscale at Week 16: Baseline Observation Carried Forward (BOCF). ClinicalTrials.gov · 2026-09-01
55 phase4, 52 phase1, 49 phase2, 45 phase3, 23 na, 4 early phase1; NCT00153660; 2016-12; no ageing endpoint recorded. Last human test completed 2025, NCT05900336.
Interpretation These counts include studies where Naproxen was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase4
55
phase1
52
phase2
49
phase3
45
na
23
early phase1
4
1 more recorded row
Last recorded human testNCT05900336
2025-08-01
recorded 2026-09-01 · last checked 2026-09-04
Q3
From rat to human: where has Naproxen shown healthspan?
Change From Baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function Subscale at Week 16: Baseline Observation… — the recorded outcome words.
Show the evidence
rat
mechanism-only
humanNCT00830063
healthspan; Change From Baseline in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function Subscale at Week 16: Baseline Observation Carried Forward (BOCF); 218
recorded 2026-09-01 · last checked 2026-09-04
Q4
21 of Naproxen's trials stopped: safety, futility/efficacy, accrual/recruitment, funding/business, other?
safety (2), futility/efficacy (2), accrual/recruitment (7), funding/business (2) and other (8): Naproxen's stop wording, clustered. ClinicalTrials.gov · 2026-09-01
"Extreme toxicity"; 21 of 218 registered studies
Show the evidence
Trial
NCT00383487
terminated; "Extreme toxicity"
NCT00410995
terminated; "Study never initiated."
NCT00418782
terminated; "Results of interim analysis indicate lack of efficacy when compared to placebo."
NCT00586365
withdrawn; "Too difficult to satisfy all the inclusion criteria."
NCT00780325
terminated; "A total of three parts were planned for this study. The sponsor funded only Part 1, so that neither Part 2 nor Part 3 of this study has been conducted."
NCT00945178
terminated; "The study was terminated due to results in another study (NCT00878501)."
14 further recorded trials
NCT01147458
terminated; "See termination reason in detailed description."
NCT01442428
withdrawn; "2011 Thailand flooding led to loss of GMP pharmacy, project delays, and further regulatory challenges."
NCT01612975
terminated; "Recruitment futile"
NCT01726920
withdrawn; "Due to budget limitations, the company decided to withdraw this study."
NCT01982799
withdrawn; "Not enough funding"
NCT02094807
withdrawn; "Slow inclusion rate. Awaiting results from NCT02132416."
NCT02108548
terminated; "Gastrointestinal safety findings"
NCT02502006
terminated; "Funding was not available to complete enrollment"
NCT02689024
terminated; "recruitment too slow; intervention was standard care in patients who were not included; acute care pathways changed due to policy regarding hip fracture patients"
NCT03699293
terminated; "Our group moved from Inova Heart and Vascular institute to Sinai Hospital with Platelet and Thrombosis, LLC taking over sponsorship. Study was then IRB approved at Sinai on March, 2020 but closed prior to any additional enrolment due to…"
NCT03949673
terminated; "Lack of enrollment"
NCT04015596
terminated; "Low recruitment"
NCT04038346
terminated; "Study with overlapping patient population"
NCT04115098
terminated; "lack of recruitment"
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Naproxen used PN 200 tablets (500 mg naproxen and 20 mg omeprazole) — over how long?
20 recorded entries; human; also "PN 200 tablets (500 mg naproxen and 20 mg omeprazole)", "Naproxen 500 mg tablets (PN 200 minus omeprazole)", "Naproxen Sodium 660mg"
Show the evidence
human
NCT00367211
PN 200 tablets (500 mg naproxen and 20 mg omeprazole)
NCT00367211
Naproxen 500 mg tablets (PN 200 minus omeprazole)
NCT00751556
Naproxen Sodium 660mg
NCT00751556
Commercial Aleve 220 mg
NCT00803764
Naproxen Tablets, 500 mg
NCT01052792
Anaprox DS 550 mg
14 more recorded rows
humanNCT01118273
Naproxen Sodium 440 mg (BAYH6689) / DPH 50mg
humanNCT01118273
Naproxen Sodium 440 mg (BAYH6689)
humanNCT01118273
Naproxen Sodium 220 mg (BAYH6689) / DPH 50mg
humanNCT01118273
Naproxen Sodium 220 mg (BAYH6689)
humanNCT01165307
Naprosyn 250 mg tablets
humanNCT01280591
Naproxen sodium 440 mg / DPH 50 mg (BAY98-7111)
humanNCT01280591
Naproxen sodium 220 mg / DPH 50 mg (BAY98-7111)
humanNCT01280591
Naproxen sodium 440 mg (BAYH6689)
humanNCT01495858
Naproxen Sodium 440 mg / DPH 25 mg (BAY98-7111)
humanNCT01884272
naproxen 250 mg
humanNCT01994226
Naproxen 750 mg/250 mg
humanNCT02549469
Naproxen Sodium ER (BAY117031), 20% HPMC
humanNCT02549469
Naproxen Sodium ER (BAY117031), 30% HPMC
humanNCT02549469
Naproxen Sodium ER (BAY117031), 40% HPMC
recorded 2026-09-01 · last checked 2026-09-04
Q6
Naproxen's half-life is 12 to 17 hours — which schedules were studied?
12 to 17 hours, the half-life Naproxen's label states. openfda-label · f6f4a670-235e-4235-84a8-a74dc8ca5586 · 2026-08-27
bioavailability 95% %.
Show the evidence
half life
12 to 17 hours hours; The plasma half-life of the naproxen anion in humans ranges from 12 to 17 hours.
bioavailability
95% %; Naproxen and naproxen sodium are rapidly and completely absorbed from the gastrointestinal tract with an in vivo bioavailability of 95%.
metabolism
Elimination Metabolism Naproxen is extensively metabolized in the liver to 6-0-desmethyl naproxen, and both parent and metabolites do not induce metabolizing enzymes.
recorded 2026-08-27 · last checked 2026-09-04
Q7
Which of 1st peak rms knee index, acr 20 criteria responder and acr pediatric 30 did Naproxen's trials measure?
1st peak rms knee index, acr 20 criteria responder and acr pediatric 30 lead 40 outcome terms across Naproxen's trials. ClinicalTrials.gov · 2026-09-01
s assessment of arthritis pain, acr 20 criteria responder, s assessment of arthritis pain using a visual analogue scale, acr pediatric 30, pk parameters and pressure pain threshold area under the curve follow.
Show the evidence
numerical rating scale
1
womac
1
monitored for long term safety of pn 400
1
s assessment of arthritis pain
1
acr 20 criteria responder
1
s assessment of arthritis pain using a visual analogue scale
1
14 more recorded rows
acr pediatric 30
1
pk parameters
1
pressure pain threshold area under the curve
1
pharmacokinetics parameters
1
pharmacokinetics
1
study compound s biochemical selectivity for cox 2
1
bleeding and spotting days
1
systolic blood pressure at week 6/final visit
1
treatment success event rates in each group
1
perimetric mean deviation
1
bioequivalence based on cmax and auc parameters
1
safety assessments
1
safety
1
part a number of intolerance events
1
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which of Naproxen's 15 ongoing trials reports first?
Frequency of gout flare; To establish the effect of naproxen or aspirin on the abundance of T cells and other immune; latest 2031-12-01
Show the evidence
Trial
NCT04875702
"Treat-to-Target Serum Urate Versus Treat-to-Avoid Symptoms in Gout"; n 650; "Frequency of gout flare"; 2028-10-31
NCT05411718
"A Phase IIa Randomized, Double-Blinded Clinical Trial of Naproxen or Aspirin for Cancer Immune Interception in Lynch Syndrome"; n 40; "To establish the effect of naproxen or aspirin on the abundance of T cells and other immune"; 2026-11-30
NCT05430230
"Study of Nonsteroidal Anti-inflammatory Drugs in People With Painful Knee Osteoarthritis"; n 20; "Mean of one week's daily pain ratings on Numeric Pain Scale (NRS) 0-10; higher worse"; 2027-09-01
NCT05463367
"Project 1 Aim 2, Adaptations of the Brain in Chronic Pain With Opioid Exposure"; n 60; "Differences across drugs in Withdrawal relief assessed by Pain and Craving Index (PCI)."; 2025-06-01
NCT05851976
"Duloxetine for LBP"; n 120; "Number of participants with moderate or severe Low Back Pain (LBP)"; 2027-05
NCT06274151
"Optimal Treatment of Acute Skeletal Muscle Injury"; n 20; "Effect of anti-inflammatory medicine on cellular profile in skeletal muscle"; 2029-12-31
9 further recorded trials
NCT06562816
"Comparing Trypsin-Chymotrypsin and Naproxen Sodium for Post-endodontic Treatment Pain"; n 100; "Change in post-endodontic treatment pain score using Numeric Rating Scale"; 2025-01-31
NCT06861920
"NSAID Use for Treating Dysmenorrhea and Preventing Chronic Pelvic Pain (NSAID HEAL)"; n 600; "M1 = Non-Menstrual Pelvic Pain (NMPP) Mediation by Menstrual Pain"; 2030-07
NCT06903585
"Non Steroidal Anti-inflammatory Drugs in the Prevention of Bone Pain Flares After Palliative Radiotherapy"; n 385; "Occurrence of a pain flare within the first 10 days after palliative radiation therapy"; 2029-04
NCT06917118
"Multimodal Pain Management After Wide Awake Local Anesthesia No Tourniquet Orthopedic Hand Surgery: A Randomized Control Trial"; n 100; "VAS Pain Scores"; 2025-12-01
NCT07277712
"A Study to Evaluate the Pharmacokinetics and Food-effect of IN-M00002 Tablet in Healthy Adult Volunteers"; n 74; "AUCt of tegoprazan"; 2026-09-30
NCT07549490
"Human Experimental Models of Pain (HEMP)"; n 25; "Change from baseline in pain intensity after cold pressor test"; 2030-12-31
NCT07665476
"Naproxen Versus Placebo as Adjunct Treatment of Cellulitis"; n 884; "Number of Participants with Early Clinical Response Assessed by Change in Lesion Area (cm²)"; 2031-12-01
NCT07743606
"NSAIDS Following Elective Lumbar Spine Fusion"; n 428; "Revision surgery for symptomatic lumbar spinal fusion nonunion"; 2028-12-31
NCT07750639
"Reducing Opioid Use After Upper Extremity Surgery: Testing Lower Prescriptions and Pill Quantity"; n 260; "Number of Participants Requesting an Additional Postoperative Pain Medication Refill"; 2026-10-14
recorded 2026-09-01 · last checked 2026-09-04
Q9
Which 87 trials of Naproxen posted no result?
Posted no result
87 of 87 completed trials
Registrations
NCT00004845, NCT00092729, NCT00240773, NCT00648258, NCT00652808 and NCT00434083, and 81 more
Completion dates
oldest 2001-12; newest 2024-08-20
Show the evidence
Trial
NCT00004845
2001-12
NCT00092729
2002-12-06
NCT00240773
2003-06
NCT00648258
2004-04
NCT00652808
2004-09
NCT00434083
2005-01
14 further recorded trials
NCT00643799
2005-01
NCT00650455
2005-01
NCT00433732
2005-04
NCT00652925
2005-04
NCT00137033
2005-07
NCT01052129
2006-05
NCT01052792
2006-06
NCT00303017
2006-09
NCT00366262
2007-03
NCT00222976
2007-05
NCT02549469
2007-05
NCT00367211
2007-09
NCT00542555
2007-09
NCT00928837
2007-09
Q10
At the median, Naproxen's trials enrolled 100 people — anything larger?
Median enrolment
100
Largest enrolment
24081
Registered trials counted
213
Q11
What do 6316 spontaneous reports say about Naproxen — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Naproxen appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 6316 reaction mentions were counted: drug hypersensitivity 1152; pain 769; vomiting 686; rash 675. open-targets-adr · CHEMBL1200806 · 2026-06-24
Show the evidence
drug hypersensitivity
1152
pain
769
vomiting
686
rash
675
arthralgia
639
condition aggravated
524
4 more recorded rows
drug intolerance
508
gastrointestinal haemorrhage
456
synovitis
456
acute kidney injury
451
recorded 2026-06-24 · last checked 2026-09-04
Q12
Was Naproxen studied with fasting and exercise?
fasting and exercise are named in Naproxen's label sentences: "Its pharmacokinetic profile after single and multiple dosing was compared to immediate release (IR) naproxen sodium in two randomized, open-label, crossover studies, under fasting and fed conditions." openfda-label+europepmc · 2025-04-01
2 recorded statements; fasting, exercise
Show the evidence
fasting
Its pharmacokinetic profile after single and multiple dosing was compared to immediate release (IR) naproxen sodium in two randomized, open-label, crossover studies, under fasting and fed conditions.
exercise
The purpose of this study was to compare the effects of three different NSAIDS: naproxen sodium, ibuprofen, flurbiprofen or a placebo on musculoskeletal adaptations in rodents with or without 6 weeks of aerobic exercise.
recorded 2025-04-01 · last checked 2026-09-04
Q13
What is recorded about Naproxen and autophagy?
"The non-selective COX inhibitor indomethacin (IND) can be nephrotoxic, but the impact of selective COX-2 inhibitor celecoxib (CEL) or the non-selective naproxen (NAP) on renal autophagy and EGR1 remain obscure." — where Naproxen and autophagy appear together. Europe PMC · pathway abstract search · 2026-01-01
"The non-selective COX inhibitor indomethacin (IND) can be nephrotoxic, but the impact of selective COX-2 inhibitor celecoxib (CEL) or the non-selective naproxen (NAP) on renal autophagy and EGR1 remain obscure."
mTOR
PMID 42602154
"Selective adjunctive strategies, most notably mTOR inhibition with sirolimus and combination clarithromycin-naproxen-oseltamivir, show early hypothesis-generating signals but require confirmatory trials."
PMID 40242503
"Furthermore, <b>CIME</b> is successfully created by the introduction of a temporally on-demand regulatory system: naproxen anti-inflammatory drugs are preferentially released to regulate M1/M2 macrophage polarization through PI3K/Akt/mTOR signaling pathway at early stage, while TGFβ3/CTGF growth factors are on-demand released to promote fibrochondrogenic differentiation of stem cells in the…"
AMPKPMID 28977822
"EIS Regimen uses the antifungal drug itraconazole to block Hedgehog signaling, the antidiabetes drug metformin to block AMP kinase (AMPK), the analgesic drug naproxen to block Rac1, the anti-fibrosis drug pirfenidone to block transforming growth factor-beta (TGF-beta), the psychiatric drug quetiapine to block receptor activator NFkB ligand (RANKL) and the antibiotic rifampin to block Wnt- all by…"
IGF-1
PMID 16257278
"Conversely, only the high OA group showed a significant inhibition of IGF-1 production when PGE2 synthesis was reduced with Naproxen, a non-steroidal antiinflammatory drug (NSAID) that inhibits cyclooxygenases (COX)."
PMID 8675801
"Agents tested included Demecolcine (an inhibitor of cytoskeletal contraction), growth factors (i.e., TGF-beta 1, PDGF, and IGF-1), and non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin, ibuprofen, naproxen, and flurbiprofen)."
recorded 2026-01-01 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
Naproxen sodium anhydrous, Naproxen sodium component of aleve-d, Naproxen sodium component of treximet, Naproxen sodium salt, Good Sense Naproxen Sodium
Sources (11)
Sources
ClinicalTrials.govclinicaltrials.gov ·
ClinicalTrials.govClinicalTrials.gov API v2 snapshot 2026-09-01T09:00:05 ·
ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · Open Targets 26.06 — CC0 · derived from this page's own recorded fields; no external licence · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
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