This page shows what was measured, who it was measured in, and what that does not settle.
What Sulfasalazine does in the body
One half, an aspirin relative, stays in the colon and calms the inflamed lining there.
Sulfasalazine is two molecules chemically welded together by a bond that human enzymes cannot cut and gut bacteria can. Swallowed, it passes almost untouched through the stomach and small intestine and arrives in the colon, where bacteria break the weld and release both halves. The other half, a sulfa antibiotic, is absorbed into the bloodstream and is the part that acts on rheumatoid arthritis. Which half matters depends entirely on which disease is being treated.
Why people take it. Ulcerative colitis and rheumatoid arthritis
What happened in people
No significant difference in radiographic progression, pain, quality of life or major adverse events between those two regimens in RACAT
✎ 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.
RACAT made a twenty-cent tablet the comparator that a TNF inhibitor had to beat, and it did not
Where it acts
Two different places, depending on the disease. For colitis the colon lumen and epithelium, where gut bacteria split the molecule and release the active half locally. For rheumatoid arthritis, the systemic circulation, which the other half reaches after absorption.
Kind of result
Symptoms and quality of life
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · 3XC8GUZ6CB · read 2026-08-29
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
The recorded use, written for a reader without medical training. Not signed off.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 115 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.
Receptor
A receptor is a part of a cell that a signal fits into.
A picture of it, and where the picture fails
A receptor is like a lock waiting for one key.
Where that stops being true. A lock either opens or does not. A receptor can be half-triggered, or worn out.
What people get wrong. Fitting a receptor is read as causing a benefit. It causes a step, and nothing more.
A protein that binds a specific ligand and converts that binding into a cellular response.
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 reviewer1 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
pain
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
1 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.
Change in DAS28 from baseline to week 48
✓ The study showed what it set out to show
Who was studied
RACAT / CSP 551 (NCT00405275)
How many people
353
Study design
Phase 4, randomised, double-blind, non-inferiority, with blinded switch at 24 weeks
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
-2.1 with triple therapy against -2.3 with etanercept plus methotrexate, P=0.26; non-inferiority met with a 95% upper confidence limit of 0.41 against a margin of 0.6, P=0.002
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. Non-inferiority, not equivalence or superiority: the point estimate favoured the biologic by 0.2 DAS28 points. Twenty-seven percent of each group required a blinded switch at 24 weeks, so this compares strategies rather than fixed regimens.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Immediate-release oral tablet and delayed-release (enteric-coated) oral tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
No difference in mean DAS28-ESR over weeks 48 to 102 between methotrexate plus etanercept and oral triple therapy, whether started immediately or stepped up at week 24
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. Radiographic progression did differ and favoured the biologic: change from baseline 0.64 with methotrexate plus etanercept against 1.69 with oral triple therapy, P=0.047. A clinical equivalence with a radiographic difference is exactly the finding most likely to be quoted as one thing or the other.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Immediate-release oral tablet and delayed-release (enteric-coated) oral tablet
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 2 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 eventEvidence recorded. Death, a heart attack, a stroke, a hospital stay.4 registered measures of this kind. No reviewed result.
■What a body can do day to dayEvidence recorded. Walking, dressing, breathing, recovering.1 registered measure of this kind.
■Measured performanceEvidence recorded. How much was lifted, how far was run, how fast.1 registered measure of this kind.
■Symptoms and quality of lifeEvidence recorded. Pain, tiredness, mood, sleep, as the person rated it.1 registered measure of this kind.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.9 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 Mouse, 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
Intestines: In the intestine, sulfasalazine is metabolized by intestinal bacteria to sulfapyridine and 5-aminosalicylic acid; sulfapyridine is relatively well absorbed from the intestine while 5-aminosalicylic acid is much less well absorbed
US prescribing information · 029716bd-ee1a-484c-bf1f-ec8d02d5281b · read 2026-08-28
Start
Sulfasalazine
What a person takes: Immediate-release oral tablet and delayed-release (enteric-coated) oral tablet.
The measurement behind this step
A colon-targeted prodrug in which the targeting is biological rather than pharmaceutical: the azo bond is cleaved only by bacterial azoreductases, which exist in the colon and not in human tissue. Only about 10 to 30% of an oral dose is absorbed intact, and much of that returns to the gut in bile. The enteric-coated form exists to reduce upper gastrointestinal irritation and is the presentation used for rheumatoid arthritis. Absorption of the liberated sulfapyridine, and therefore systemic toxicity, depends on NAT2 acetylator phenotype.
Getting in
Swallowed whole and almost entirely not absorbed
Most drugs are designed to be absorbed. This one is designed not to be. Between seven and nine tenths of a dose passes through the stomach and small intestine untouched.
╌╌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
Only about 10 to 30% of intact sulfasalazine is absorbed from the small intestine, and much of that is returned to the gut lumen in bile. The molecule is large, dianionic at intestinal pH and a poor passive-diffusion substrate — properties that would normally count as a formulation failure and are here the whole point.
The bond joining the two halves can only be broken by bacterial enzymes, and those bacteria live in the colon. The drug therefore releases itself exactly where colitis is.
╌╌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
Bacterial azoreductases reduce the azo bond, liberating sulfapyridine and 5-aminosalicylic acid. Humans have no equivalent enzyme, which makes the colon the only site of activation. Suppression of colonic flora by antibiotics reduces cleavage and therefore the delivered dose of both moieties.
The aspirin relative is poorly absorbed from the colon, so it sits on the inflamed lining at high concentration and low body-wide exposure.
──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
5-aminosalicylic acid acts locally on colonic epithelium, with described actions including PPAR-gamma agonism, inhibition of NF-kappaB activation, scavenging of reactive oxygen species and inhibition of leukotriene synthesis. It is largely acetylated in the mucosa and excreted in faeces. In the moiety experiment it produced pronounced histological improvement in about 30% of patients against 5% for sulfapyridine.
The sulfa antibiotic is absorbed from the colon into the bloodstream. It is the part that treats rheumatoid arthritis, and nobody is entirely sure how.
╌╌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
Sulfapyridine is absorbed, acetylated in the liver at a rate set by NAT2 acetylator phenotype, and excreted renally. Slow acetylators reach higher serum concentrations and experience more toxicity. Its disease-modifying mechanism in rheumatoid arthritis is not established; candidate actions include inhibition of NF-kappaB, inhibition of AICAR transformylase with consequent adenosine release, suppression of angiogenesis, and an effect on gut or oral bacteria.
The colitis improvement comes from the half that stayed behind, and the arthritis improvement from the half that travelled. Two moiety experiments, done eight years apart, established which was which.
╌╌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
Histological improvement in ulcerative colitis in about 30% with sulfasalazine or 5-ASA against 5% with sulfapyridine; a pronounced second-line effect in rheumatoid arthritis with sulfapyridine comparable to sulfasalazine, and only a weak first-line effect with 5-ASA. In RACAT, a regimen containing sulfasalazine produced a DAS28 change of -2.1 against -2.3 for etanercept plus methotrexate.
Nausea, headache, rash and a reversible drop in sperm count all track with the sulfa half. In colitis, that half does no useful work, which is why a whole class of successor drugs exists to deliver the other half alone.
╌╌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
Sulfapyridine-related adverse effects scale with serum concentration and therefore with acetylator phenotype. Severe labelled reactions include Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS, agranulocytosis and aplastic anaemia. Reversible oligospermia resolves within months of stopping. The mesalazine class exists precisely because the 1977 experiment made this trade-off indefensible in colitis.
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.
pain
Measured
Things only a test, a scale or a device shows.
brachial artery flow mediated dilation
maximum concentration at steady state
minimum concentration at steady state
average concentration of administration interval
time of maximum concentration
area under the concentrations time curve
maximum concentration
vascular inflammation as measured by fdg pet/ct at 6 months
area under the concentration time curve
Meaningful
Things that change how a life goes, not only a number.
remission according to das28 crp at week 16
remission according to das28 crp at week 52
remission according to das28 crp at week 104
health assessment questionnaire disability index at week 12
clinical remission
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)
disease activity erythrocyte sedimentation rate
48 week change in das28
asas20
whole gut transit time
renal clearance
area under the curve of administration window
oro cecal transit time
average whole gut transit time
renal clearances
terminal half life
residence time
distribution volume at steady state
total body clearance
treatment emergent adverse events
validated aid associated product technical failures
clinical failures
treatment emergent adverse events and serious adverse events
achieving good eular response at the end of 12 weeks
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. 7.6 ± 3.4 hours hours
Read from the label, which states: “The observed plasma half-life for intravenous sulfasalazine is 7.6 ± 3.4 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.
People with ulcerative colitis, particularly where the disease is confined to the colon; people with rheumatoid arthritis, usually as part of triple therapy with methotrexate and hydroxychloroquine; and people with ankylosing spondylitis with peripheral joint involvement.
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: “The safety and effectiveness of sulfasalazine delayed release tablets in pediatric patients below the age of 2 years with ulcerative colitis have not been established.”
US prescribing information · 257cee60-b68f-4c2b-b57d-8e4d73d17e09 · read 2026-08-30
On people who are pregnant, the label states: “There are no adequate and well-controlled studies of sulfasalazine in pregnant women.”
US prescribing information · 257cee60-b68f-4c2b-b57d-8e4d73d17e09 · read 2026-08-30
On people who are breastfeeding, the label states: “Sulfonamides, including sulfasalazine, are present in human milk (see Pregnancy, Clinical Considerations ).”
US prescribing information · 257cee60-b68f-4c2b-b57d-8e4d73d17e09 · read 2026-08-30
Where the result stopped carrying
The bacterial theory of rheumatoid arthritis that the drug was designed around was abandoned; the drug survived it
Sulfapyridine, the carrier, produces most of the adverse effects and does no useful work in colitis, which cost sulfasalazine that indication to the mesalazine class
Separating the moieties in rheumatoid arthritis identified the active half but not a better-tolerated one: sulfapyridine alone had a similar toxicity profile to the parent
The drug does nothing at all until bacteria act on it, so its delivered dose is outside both the prescriber’s and the patient’s control
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 change is too small to feel
A real change can still sit below what a person notices.
On this record: RACAT made a twenty-cent tablet the comparator that a TNF inhibitor had to beat, and it did not
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 (9)
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.
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
Immediate-release oral tablet and delayed-release (enteric-coated) oral tablet
✎ 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
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
A colon-targeted prodrug in which the targeting is biological rather than pharmaceutical: the azo bond is cleaved only by bacterial azoreductases, which exist in the colon and not in human tissue.
✎ 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: Only about 10 to 30% of an oral dose is absorbed intact, and much of that returns to the gut in bile. The enteric-coated form exists to reduce upper gastrointestinal irritation and is the presentation used for rheumatoid arthritis. Absorption of the liberated sulfapyridine, and therefore systemic toxicity, depends on NAT2 acetylator phenotype.
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
Most adverse effects track the sulfapyridine moiety and its serum concentration: nausea, headache, rash, and reversible oligospermia in men, which resolves within months of stopping. Labelled serious reactions include Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, agranulocytosis, aplastic anaemia and hepatotoxicity, which is why blood counts and liver tests are monitored in the early months. Contraindicated in sulfonamide or salicylate hypersensitivity and in intestinal or urinary obstruction. It interferes with folate absorption, and it turns urine and sometimes skin yellow-orange and can permanently stain soft contact lenses.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
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.
Sulfasalazine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 36567 reaction mentions were counted. One report can name several reactions.
The recorded terms (10)
rheumatoid arthritis — 6080 reaction mentions
drug intolerance — 4705 reaction mentions
pain — 4189 reaction mentions
joint swelling — 3592 reaction mentions
fatigue — 3220 reaction mentions
arthralgia — 3149 reaction mentions
treatment failure — 3092 reaction mentions
rash — 2976 reaction mentions
alopecia — 2785 reaction mentions
drug hypersensitivity — 2779 reaction mentions
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
Immediate-release oral tablet and delayed-release (enteric-coated) oral tablet
✎ 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
Only about 10 to 30% of an oral dose is absorbed intact, and much of that returns to the gut in bile. The enteric-coated form exists to reduce upper gastrointestinal irritation and is the presentation used for rheumatoid arthritis. Absorption of the liberated sulfapyridine, and therefore systemic toxicity, depends on NAT2 acetylator phenotype.
✎ 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 which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
24 products list this as an active ingredient in the United States drug directory. 24 of them contain it and nothing else.
FDA National Drug Code directory · 59116-0633 · read 2026-08-29
They are sold as powder, tablet and tablet, delayed release, taken oral.
FDA National Drug Code directory · 59116-0633 · read 2026-08-29
The regulator's established pharmacologic class for it is aminosalicylate [epc] and aminosalicylic acids [cs].
FDA National Drug Code directory · 59116-0633 · read 2026-08-29
14 published labels name it as an active ingredient. 14 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 257cee60-b68f-4c2b-b57d-8e4d73d17e09 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 257cee60-b68f-4c2b-b57d-8e4d73d17e09 · read 2026-08-29
Sulfasalazine is tablets at Tablets, USP 500 mg, recorded as prescription product; fda label in effect 2022-12-12 in the United States.
US prescribing information · 029716bd-ee1a-484c-bf1f-ec8d02d5281b · read 2026-08-28
Recorded price in US: 0.20034 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 12 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.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Sulfasalazine 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 sulfapyridine working in rheumatoid arthritis supports a bacterial cause of the disease — the observation is real and the inference is still open
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 triple therapy is as good as or better than a TNF inhibitor; the trial established non-inferiority within a 0.6 margin with the point estimate favouring the biologic
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 variation in colonic azoreductase activity changes clinical outcome — mechanistically certain and never measured against one
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 same molecule works the same way in both its licensed diseases; two experiments established the opposite
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 Sulfasalazine 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.
Designed on a wrong hypothesis, and it works for a different reason
In plain words
Nanna Svartz built this drug in the late 1930s from a sulfa antibiotic and an aspirin relative, because she thought rheumatoid arthritis was caused by a streptococcal infection. That theory was abandoned. The drug turned out to work in two diseases, and the antibiotic half is the part that does the work in arthritis — which is not evidence that the theory was right, and is the reason the question keeps being asked.
What was measured
That sulfapyridine working in rheumatoid arthritis supports a bacterial cause of the disease — the observation is real and the inference has never been closed either way
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Sulfasalazine was synthesised as a deliberate conjugate of sulfapyridine, an antibacterial sulfonamide, and 5-aminosalicylic acid, an anti-inflammatory salicylate, on the working hypothesis that rheumatoid arthritis had a bacterial aetiology and that a drug combining antibacterial and anti-inflammatory activity would target it. The infectious theory of rheumatoid arthritis was not sustained. Two separate moiety experiments, decades apart, then established that different halves carry the effect in the drug’s two diseases. In the arthritis experiment the authors noted explicitly that the efficacy of the antibacterial component "yet again permits speculation about the role of a bacterial pathogen in the aetiopathogenesis of rheumatoid disease" — a speculation that remains unresolved, with the modern version framed around the gut and oral microbiome rather than around a single organism.
Written into the record, not signed off as a reviewed claim
The 1977 enema experiment: 5-ASA is the active half in colitis
In plain words
Three groups of patients with active ulcerative colitis were given nightly enemas of either the whole drug, or one half, or the other half, for two weeks. The whole drug and the salicylate half produced about the same improvement on biopsy. The antibiotic half produced almost none.
What was measured
Histological improvement on biopsy after two weeks of moiety-specific retention enemas
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Retention enemas of sulfasalazine, sulfapyridine or 5-aminosalicylic acid were given daily for two weeks to patients with sigmoidoscopic evidence of active ulcerative colitis, in a blind controlled trial with each patient receiving one preparation. Pronounced histological improvement was observed in approximately 30% of patients receiving sulfasalazine or 5-aminosalicylic acid, and in only 5% of those receiving sulfapyridine. The authors concluded that the active therapeutic moiety is 5-ASA and that sulfapyridine functions as a carrier ensuring the 5-ASA is liberated in the colon. That conclusion created the entire mesalazine class, which is sulfasalazine with the carrier removed and a formulation put in its place.
Written into the record, not signed off as a reviewed claim
The 1985 experiment: sulfapyridine is the active half in arthritis
In plain words
The same question was asked in rheumatoid arthritis and got the opposite answer. Given separately over twenty-four weeks, the antibiotic half worked about as well as the whole drug. The salicylate half — the one that works in colitis — barely did anything.
What was measured
Second-line disease-modifying effect over 24 weeks with each moiety administered separately
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Sulfapyridine and 5-aminosalicylic acid were assessed separately over 24 weeks in the treatment of rheumatoid arthritis. Sulfapyridine showed a pronounced second-line effect comparable with sulfasalazine and with a similar toxicity profile, whereas 5-aminosalicylic acid showed only a weak first-line effect. The authors concluded that sulfapyridine is the active moiety responsible for the second-line effect in rheumatoid arthritis. Taken with the 1977 colitis experiment, this establishes that a single marketed molecule delivers its benefit through opposite halves in its two licensed indications — an unusual situation, and the reason the mesalazine class replaced sulfasalazine in colitis while sulfasalazine itself remains in rheumatology.
Written into the record, not signed off as a reviewed claim
RACAT: triple therapy matched a biologic over 48 weeks
In plain words
Three hundred and fifty-three people with rheumatoid arthritis still active on methotrexate were randomly given either two cheap old tablets added on, or an injected biologic. After a year the disease scores were the same, and so were the X-rays. The tablets cost cents; the biologic costs tens of thousands a year.
What was measured
Change in DAS28 from baseline to week 48, non-inferiority against etanercept plus methotrexate, double-blind
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
RACAT was a 48-week double-blind non-inferiority trial in 353 participants with rheumatoid arthritis active despite methotrexate, randomised to triple therapy — methotrexate, sulfasalazine and hydroxychloroquine — or to etanercept plus methotrexate, with blinded switching at 24 weeks for those below a prespecified improvement threshold. Twenty-seven percent in each group switched. The change in DAS28 between baseline and 48 weeks was -2.1 with triple therapy and -2.3 with etanercept plus methotrexate (P=0.26); non-inferiority was met, with the 95% upper confidence limit of 0.41 below the prespecified margin of 0.6 (P=0.002). There were no significant between-group differences in radiographic progression, pain, health-related quality of life, or major adverse events. Response after switching did not differ significantly between groups (P=0.08).
Written into the record, not signed off as a reviewed claim
Non-inferiority is not equivalence, and the trial says what it says
In plain words
RACAT showed the cheap combination was not meaningfully worse than the biologic. It did not show the two were identical, and it was not designed to. The distinction matters because the result is often reported as though the biologic had been beaten.
What was measured
That triple therapy is as good as, or better than, a TNF inhibitor — the trial established non-inferiority within a 0.6 DAS28 margin, with the point estimate favouring the biologic by 0.2
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The prespecified non-inferiority margin was a DAS28 difference of 0.6. The observed difference favoured etanercept plus methotrexate by 0.2 points with a 95% upper confidence limit of 0.41 — inside the margin, and pointing the same direction. A non-inferiority design establishes that the difference is smaller than a stated threshold of clinical importance; it does not establish that there is no difference, and it cannot establish superiority. Both arms also included a blinded switch at 24 weeks for non-responders, which was used by 27% of each group, so the 48-week comparison is of strategies rather than of fixed regimens. The finding is important and the correct statement of it is narrower than the headline.
Written into the record, not signed off as a reviewed claim
The carrier half causes most of the harm, which is why it was removed
In plain words
The sulfa half of the molecule is responsible for most of the side effects — rash, headache, nausea and a reversible drop in sperm count. Once it was established that this half did nothing useful in colitis, the obvious move was to deliver the other half on its own, and that is what the mesalazine drugs are.
What was measured
Histological response by moiety in colitis, and the consequent removal of the sulfonamide carrier from the treatment class
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Adverse effects attributable to the sulfapyridine moiety include nausea, headache, rash and reversible oligospermia, with incidence related to serum sulfapyridine concentration and therefore to acetylator phenotype: slow acetylators reach higher concentrations and experience more toxicity. Severe reactions on the label include Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, agranulocytosis and aplastic anaemia. The 1977 finding that 5-ASA carried the colitis effect made the carrier’s toxicity indefensible in that indication and created the mesalazine class — pH-dependent, time-dependent and azo-bonded formulations of 5-ASA without any sulfonamide. In rheumatoid arthritis the same reasoning cannot be applied, because there the sulfapyridine is the active moiety.
Written into the record, not signed off as a reviewed claim
The drug depends on the patient’s gut bacteria to work at all
In plain words
Nothing happens until bacteria in the colon cut the molecule in half. That means the delivered dose depends on the person’s microbiome, and a course of antibiotics can reduce it. This is rarely discussed and has never been measured against a clinical outcome.
What was measured
That variation in colonic azoreductase activity meaningfully changes clinical response — mechanistically certain, and never measured against an outcome
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Sulfasalazine is cleaved by bacterial azoreductases, an activity concentrated in the colon and absent from the human enzyme repertoire. Only about 10 to 30% of an oral dose is absorbed intact in the small intestine, and much of that returns to the gut in bile. Antibiotic-induced suppression of colonic flora reduces azoreduction and therefore reduces liberation of both moieties. The pharmacological consequence — a dose delivered that varies with the composition of an individual microbiome, and that a course of antibiotics can alter — is well described in vitro and in pharmacokinetic studies. What has not been done is a clinical study relating measured azoreductase activity or microbiome composition to disease outcome, so the practical significance is inferred from the mechanism rather than measured.
Written into the record, not signed off as a reviewed claim
A twenty-cent tablet is on the essential medicines list for two diseases
In plain words
The whole molecule is made in one step of nineteen-thirties dye chemistry, and it costs about twenty cents a tablet at what American pharmacies pay. That price is the reason a trial comparing it against a biologic mattered.
What was measured
United States pharmacy acquisition cost per tablet, alongside a 48-week non-inferiority result against a biologic
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Sulfasalazine is manufactured by diazotisation of sulfapyridine and azo coupling to salicylic acid — a single-vessel reaction sequence developed for the dye industry. The CMS National Average Drug Acquisition Cost file lists generic sulfasalazine at US$0.2003 per tablet. Sulfasalazine appears on the WHO Model List of Essential Medicines. The economic significance of RACAT follows directly: a regimen whose two added components cost a few dollars a month was found non-inferior over 48 weeks to a biologic priced at tens of thousands of dollars a year, with no significant difference in radiographic progression, pain, quality of life or major adverse events.
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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 sulfa antibiotic tied to an aspirin relative by a bond only colonic bacteria can cut — designed on a bacterial theory of rheumatoid arthritis that proved false, it works in both of its diseases through opposite halves of the molecule (5-aminosalicylic acid produced histological improvement in about 30% of colitis patients against 5% for sulfapyridine, while sulfapyridine carried the arthritis effect), and in 353 randomised patients it was part of a triple regimen non-inferior to etanercept plus methotrexate, DAS28 change -2.1 against -2.3, P=0.26.
Recorded evidence blocks (12)
Q1
What did Sulfasalazine's largest trial (2500 people) and its longest (32 years) measure?
2500 people in Sulfasalazine's largest registered study, 32 years in its longest registered window, measuring Sulfasalazine Steady State Maximum Plasma Concentration (Cmax) and Predose Concentration (Cmin). ClinicalTrials.gov · 2026-09-01
14 phase2, 14 phase3, 14 phase4, 13 phase1, 4 na, 3 na or unstated, 1 early phase1; NCT04725422; 2050-08; no ageing endpoint recorded. Last human test completed 2026, NCT03561584.
Interpretation These counts include studies where Sulfasalazine 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
phase2
14
phase3
14
phase4
14
phase1
13
na
4
na or unstated
3
2 more recorded rows
early phase1
1
Last recorded human testNCT03561584
2026-03-03
recorded 2026-09-01 · last checked 2026-09-04
Q2
From mouse to human: where has Sulfasalazine shown biomarker?
"Study terminated on 13 April 2016 for business reasons. No safety and/or efficacy concerns contributed to the termination of the study"; 4 of 58 registered studies
Show the evidence
Trial
NCT00637780
terminated; "Study terminated on 13 April 2016 for business reasons. No safety and/or efficacy concerns contributed to the termination of the study"
NCT01667029
terminated; "poor enrollment"
NCT02099240
terminated; "Not enough patient enrollment and lack of staffing"
NCT02930343
terminated; "Due to time constraints, the study was halted prematurely"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Sulfasalazine used sulfasalazine 500 MG — over how long?
Sulfasalazine's half-life is 7.6 ± 3.4 hours — which schedules were studied?
7.6 ± 3.4 hours, the half-life Sulfasalazine's label states. openfda-label · b9ef541a-93c8-4428-ba45-398aa0b327d1 · 2026-08-28
bioavailability less than 15% for parent drug %.
Show the evidence
half life
7.6 ± 3.4 hours hours; The observed plasma half-life for intravenous sulfasalazine is 7.6 ± 3.4 hours.
bioavailability
less than 15% for parent drug %; In vivo studies have indicated that the absolute bioavailability of orally administered SSZ is less than 15% for parent drug.
recorded 2026-08-28 · last checked 2026-09-04
Q6
Could one person measure Sulfasalazine's effect on disease activity erythrocyte sedimentation rate?
Disease activity erythrocyte sedimentation rate: measured in Sulfasalazine's trials.
Interpretation disease activity erythrocyte sedimentation rate is the recorded endpoint.
1; NCT03797872; PHASE4; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; COMPLETED
Q7
Which of 48 week change in das28, achieving good eular response at the end of 12 weeks and area under the concentration time curve did Sulfasalazine's trials measure?
48 week change in das28, achieving good eular response at the end of 12 weeks and area under the concentration time curve lead 40 outcome terms across Sulfasalazine's trials. ClinicalTrials.gov · 2026-09-01
asas20, remission according to das28 crp at week 16, remission according to das28 crp at week 52, remission according to das28 crp at week 104, whole gut transit time and renal clearance follow.
Show the evidence
disease activity erythrocyte sedimentation rate
1
48 week change in das28
1
brachial artery flow mediated dilation
1
asas20
1
remission according to das28 crp at week 16
1
remission according to das28 crp at week 52
1
14 more recorded rows
remission according to das28 crp at week 104
1
whole gut transit time
1
renal clearance
1
area under the curve of administration window
1
maximum concentration at steady state
1
minimum concentration at steady state
1
average concentration of administration interval
1
time of maximum concentration
1
oro cecal transit time
1
average whole gut transit time
1
renal clearances
1
area under the concentrations time curve
1
maximum concentration
1
terminal half life
1
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which of Sulfasalazine's 10 ongoing trials reports first?
Efficacy of Disease-modifying Antirheumatic Drugs Therapy for Rheumatoid Arthritis; The change of CNO disease activity score; latest 2050-08
Show the evidence
Trial
NCT03414502
"Treatment of Rheumatoid Arthritis With DMARDs: Predictors of Response"; n 400; "Efficacy of Disease-modifying Antirheumatic Drugs Therapy for Rheumatoid Arthritis"; 2029-03
NCT04725422
"CHronic Nonbacterial Osteomyelitis International Registry"; n 2000; "The change of CNO disease activity score"; 2050-08
NCT05580861
"Sulfasalazine in AML Treated by Intensive Chemotherapy: Elderly Patients-first Line Treatment"; n 64; "Dose Limiting Toxicity (for phase I part of the trial)"; 2026-12
NCT05664464
"Glutamate Inhibitors in Glioblastoma"; n 120; "PFS-6"; 2026-12
NCT05703425
"The Effect of Sulfasalazine on CRH Levels in Pregnant Women"; n 50; "Serum CRH levels"; 2028-06-30
NCT06134388
"Sulfasalazine in Patients With Metastatic Colorectal Cancer"; n 50; "Evaluating the change in the serum level of Ferritin"; 2026-09
4 further recorded trials
NCT06557330
"MRD Guided De-intensification of Bendamustine/Rituximab for Indolent Non-Hodgkin Lymphoma"; n 24; "PFS Evaluation"; 2028-03-30
NCT07138898
"Immunosuppressant Management in Rheumatology Patients Undergoing Elective Total Shoulder Arthroplasty"; n 80; "Incidence of wound complications"; 2028-01
NCT07726368
"Study of ECC4703 With Sulfasalazine and Pitavastatin"; n 40; "Maximum plasma concentration of sulfasalazine in the blood of participants who have taken ECC4703 (as part of called pharmacokinetic or 'PK' testing)"; 2026-12
NCT07730723
"The Effect of Nicorandil on Rheumatoid Arthritis Patients"; n 70; "Evaluation of treatment Efficacy"; 2027-07
recorded 2026-09-01 · last checked 2026-09-04
Q9
Which 14 trials of Sulfasalazine posted no result?
Posted no result
14 of 14 completed trials
Registrations
NCT00554203, NCT01596777, NCT01596764, NCT02434861, NCT02293590 and NCT03801733, and 8 more
Completion dates
oldest 2007-12; newest 2023-12-31
Show the evidence
Trial
NCT00554203
2007-12
NCT01596777
2010-05
NCT01596764
2012-01
NCT02434861
2015-08
NCT02293590
2018-01-15
NCT03801733
2018-11-24
8 further recorded trials
NCT02433184
2019-07
NCT03411798
2019-07-01
NCT04720183
2021-04-23
NCT04268394
2021-06-02
NCT03734627
2021-07-01
NCT04205357
2022-10-14
NCT05445440
2022-11-23
NCT03254589
2023-12-31
Q10
At the median, Sulfasalazine's trials enrolled 78 people — anything larger?
Median enrolment
78
Largest enrolment
2500
Registered trials counted
58
Q11
What do 36567 spontaneous reports say about Sulfasalazine — 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.
Sulfasalazine appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 36567 reaction mentions were counted: rheumatoid arthritis 6080; drug intolerance 4705; pain 4189; joint swelling 3592. open-targets-adr · CHEMBL421 · 2026-06-24
Show the evidence
rheumatoid arthritis
6080
drug intolerance
4705
pain
4189
joint swelling
3592
fatigue
3220
arthralgia
3149
4 more recorded rows
treatment failure
3092
rash
2976
alopecia
2785
drug hypersensitivity
2779
recorded 2026-06-24 · last checked 2026-09-04
Q12
What is recorded about Sulfasalazine and AMPK?
"This inhibitory effect of sulfasalazine on NF-κB-p65 could be at least in part attributed to its upstream modulation of p-AMPK, SIRT1, miRNA-132-3p and miR-375." — where Sulfasalazine and AMPK appear together. Europe PMC · pathway abstract search · 2026-02-18
"This inhibitory effect of sulfasalazine on NF-κB-p65 could be at least in part attributed to its upstream modulation of p-AMPK, SIRT1, miRNA-132-3p and miR-375."
sirtuinPMID 41703119
"This inhibitory effect of sulfasalazine on NF-κB-p65 could be at least in part attributed to its upstream modulation of p-AMPK, SIRT1, miRNA-132-3p and miR-375."
mTOR
PMID 40147801
"Sulfasalazine suppressed mTOR through activation of AMPKα in HPAECs."
PMID 40147801
"Blockage of xCT and mTOR or activation of AMPKα by existing drugs such as sulfasalazine, sirolimus, and metformin may offer readily therapeutic strategies for PAH."
PMID 37288359
"However, the expression level of p-mTOR, P62, and LC3 II was reversed after co-treatment with the agonist of mTOR MHY1485, whereas the p-NF-kB expression level was unchanged. <b>Conclusion:</b> sulfasalazine inhibited vascular smooth muscle cells proliferation and migration <i>in vitro</i> and Neointimal hyperplasia <i>in vivo</i> through NF-kB/mTOR-mediated autophagy."
autophagy
PMID 37288359
"However, the expression level of p-mTOR, P62, and LC3 II was reversed after co-treatment with the agonist of mTOR MHY1485, whereas the p-NF-kB expression level was unchanged. <b>Conclusion:</b> sulfasalazine inhibited vascular smooth muscle cells proliferation and migration <i>in vitro</i> and Neointimal hyperplasia <i>in vivo</i> through NF-kB/mTOR-mediated autophagy."
PMID 38184272
"This study aimed to investigate the relationship between ferroptosis and autophagy by targeting the defense of oxidative stress through the cystine transporter (xCT) using sulfasalazine (SASP), which is a widely employed xCT inhibitor."
AMPK
PMID 36752571
"Our results thus uncover a novel regulatory circuit of ferroptosis comprising ATM-NCOA4 in orchestrating ferritinophagy and iron bioavailability.<b>Abbreviations:</b> AMPK: AMP-activated protein kinase; ATM: ataxia telangiectasia mutated; BSO: buthionine sulphoximine; CDKN1A: cyclin-dependent kinase inhibitor 1A (P21); CQ: chloroquine; DFO: deferoxamine; DFP: deferiprone; Fer: ferrostatin-1;…"
PMID 33097833
"Mechanistically, ferroptosis inducers (erastin, sorafenib, and sulfasalazine) activated AMPK/SREBP1 signaling pathway through iron-dependent ferritinophagy, which in turn inhibited BCAT2 transcription."
autophagyPMID 24615622
"Body and muscle weights, limb muscle force, protein degradation and the ubiquitin-proteasome system, signaling pathways, oxidative stress and inflammation, autophagy, contractile and functional proteins, myostatin and myogenin, and muscle structure were evaluated in the diaphragm and gastrocnemius of LC (LP07 adenocarcinoma) bearing cachectic mice (BALB/c), with and without concomitant treatment…"
recorded 2026-02-18 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
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This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.