This page shows what was measured, who it was measured in, and what that does not settle.
What Trospium does in the body
Trospium blocks the same receptors as every other bladder antimuscarinic, so the bladder wall contracts less forcefully while it fills.
What makes it different is not what it binds but where it can go. The molecule carries a permanent electrical charge, and charged molecules cross the fatty membranes that wall off the brain very poorly. That is a physical property, not a design preference, and it is the reason this drug is reached for when the worry is cognition. The same charge means food interferes badly with absorption, and the kidneys rather than the liver do the clearing.
Why people take it. An overactive bladder — sudden urgency, going too often, and leaking — treated with a drug built not to reach the brain
What happened in people
Both pivotal trials, in 523 and 601 patients, met their dual primary endpoints from week 1 through week 12
✎ 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.
That a headache rate of 1.0% against 2.6% demonstrates absence of central nervous system effect — the cognitive effect this class produces has been shown to be unnoticeable to the patient and would never be volunteered
Where it acts
Detrusor smooth muscle of the bladder wall, reached from the bloodstream; central nervous system penetration is limited by the molecule's permanent charge
Kind of result
The kind of result is not recorded
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 · T4Y8ORK057 · read 2026-08-29
Its recorded molecular formula is C25H30NO3+, weighing 392.5.
PubChem record · 5284632 · 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 137 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.
Placebo
A placebo is a dummy treatment given so the real one can be compared with it.
A picture of it, and where the picture fails
A placebo is like a blank control in an experiment.
Where that stops being true. A blank does nothing. People given a placebo often do get better.
What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.
An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
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.
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.
Dual: change in average number of toilet voids and change in urge incontinence episodes per 24 hours
The published abstract states that trospium significantly decreased toilet void frequency and urge incontinence episodes and significantly increased volume per void, and reports no means, differences, confidence intervals or p-values
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. A 523-patient trial across 51 sites whose published abstract contains no quantified treatment effect. Onset by week 1 and sustained effect through week 12 are reported; magnitude is not.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet twice daily, and extended-release capsule once daily
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Reported as significant improvements over placebo in all primary and key secondary outcomes at weeks 1 through 12, with no effect size given in the abstract
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. Adverse events are quantified to one decimal place — dry mouth 8.7% against 3%, constipation 9.4% against 1.3%, headache 1.0% against 2.6% — while the efficacy is not quantified at all. The headache figure is the basis offered for the central-nervous-system safety claim.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral immediate-release tablet twice daily, and extended-release capsule once daily
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 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.
Start
Trospium
What a person takes: Oral immediate-release tablet twice daily, and extended-release capsule once daily.
The measurement behind this step
Both forms must be taken at least an hour before a meal, because a high-fat meal cuts absorption by 70% to 80%. The extended-release capsule halves the dry-mouth rate relative to the pooled immediate-release data by lowering the peak concentration, the same trade oxybutynin and tolterodine make with their own extended-release forms. Dose is reduced in severe renal impairment, because active tubular secretion by the kidney is the elimination route.
Getting in
Swallowed on an empty stomach, or most of it never arrives
The tablet must be taken at least an hour before eating. With a fatty meal, between seventy and eighty per cent of the dose that would otherwise be absorbed is lost.
╌╌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
Oral tablet; the immediate-release form is twice daily and an extended-release capsule is once daily. A high-fat meal reduces area under the curve and peak concentration by 70% to 80%. Absorption is poor by design consequence rather than by formulation failure: a permanently charged cation crosses the gut wall badly.
It reaches the bladder, and largely stops at the blood-brain barrier
The receptor it needs sits on the outside of the bladder muscle cell, so it can be reached from the bloodstream. The brain sits behind a fatty barrier that a charged molecule crosses poorly.
╌╌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 quaternary nitrogen carries a permanent positive charge at all physiological pH, so passive lipid diffusion is energetically unfavourable. Muscarinic receptors in the detrusor face the extracellular space and need no cell entry, so the bladder target is accessible while central penetration is limited. This is exclusion by physical chemistry rather than by receptor preference, which is the distinction from darifenacin.
It blocks acetylcholine at every muscarinic receptor it reaches
Unlike the newer drugs, trospium makes no attempt to prefer one receptor variety over another. Its selectivity is about place, not about type.
╌╌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 describes non-selective antagonism of acetylcholine at muscarinic receptors in cholinergically innervated organs, and quotes no subtype ratios. That is not an oversight: the entire design premise is anatomical exclusion, which makes subtype preference redundant. Where the drug arrives, it blocks everything; the argument is about where it arrives.
A bladder contraction needs a burst of calcium inside the muscle cell. With the receptors blocked, the burst is smaller and the involuntary squeeze while filling is blunted.
╌╌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
Loss of M3-Gq/11 coupling reduces phospholipase C activity, inositol trisphosphate falls, sarcoplasmic reticulum calcium release drops and myosin light-chain phosphorylation declines; M2 blockade removes the inhibition of adenylyl cyclase that opposes relaxation. Detrusor tone during filling falls and functional bladder capacity rises, with the reported effect present by the end of week 1.
Endpoints met, magnitude unpublished, dry mouth the lowest in the class
Both pivotal trials say the drug beat placebo on every main measure. Neither says by how much. What they do report is the dry mouth rate, which on the once-daily form was the lowest of any drug in this class.
╌╌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
Zinner 2004 (n=523) and Staskin 2007 (n=601) both report all primary and key secondary endpoints met from week 1 through week 12, with no effect size in either abstract. Dry mouth 8.7% against 3% and constipation 9.4% against 1.3% on the extended-release form; 20.1% against 5.8% on the pooled immediate-release label data. Headache 1.0% against 2.6% on placebo.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 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 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 with overactive bladder, particularly older adults already carrying anticholinergic load from other prescriptions, and people for whom the cognitive question is decisive.
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 trospium chloride tablets in pediatric patients have not been established.”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
On older people, the label states: “Of the 591 patients with overactive bladder who received treatment with trospium chloride tablets in the two U.S., placebo-controlled, efficacy and safety studies, 249 patients (42%) were 65 years of age and older.”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
On people who are pregnant, the label states: “Teratogenic Effects Pregnancy Category C : There are no adequate and well-controlled studies of trospium chloride tablets in pregnant women.”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
On people who are breastfeeding, the label states: “Trospium chloride (2 mg/kg orally and 50 mcg/kg intravenously) was excreted, to a limited extent (less than 1%), into the milk of lactating rats (primarily as parent compound).”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
On people with reduced liver function, the label states: “There is no information regarding the effect of severe hepatic impairment on exposure to trospium chloride tablets.”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
On people with reduced kidney function, the label states: “Severe renal impairment (creatinine clearance less than 30 mL/minute) significantly altered the disposition of trospium chloride tablets.”
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
Where the result stopped carrying
The reporting of both pivotal trials, whose abstracts quantify adverse events to a decimal place and quantify efficacy not at all
Absorption, in anyone who takes the tablet with food — the property that keeps the molecule out of the brain keeps it out of the bloodstream too
The two-decade opportunity to test the central-exclusion hypothesis against a cognitive or dementia endpoint, which has not been taken
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 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 (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
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 immediate-release tablet twice daily, and extended-release capsule once 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
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
Both forms must be taken at least an hour before a meal, because a high-fat meal cuts absorption by 70% to 80%. The extended-release capsule halves the dry-mouth rate relative to the pooled immediate-release data by lowering the peak concentration, the same trade oxybutynin and tolterodine make with their own extended-release forms. Dose is reduced in severe renal impairment, because active tubular secretion by the kidney is the elimination route.
✎ 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 and what that means for what is in the pack.
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
Dry mouth and constipation dominate as they do across the class, and are lower on the once-daily form than on any other oral antimuscarinic reported. There are no known cytochrome-mediated drug interactions, which follows structurally from the permanent charge. Warnings across the class apply: urinary retention, decreased gastrointestinal motility, and caution in narrow-angle glaucoma. The central nervous system claim rests on absence of volunteered central adverse events rather than on any cognitive measurement.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
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 immediate-release tablet twice daily, and extended-release capsule once 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
The extended-release capsule halves the dry-mouth rate relative to the pooled immediate-release data by lowering the peak concentration, the same trade oxybutynin and tolterodine make with their own extended-release forms. Dose is reduced in severe renal impairment, because active tubular secretion by the kidney is the elimination route.
✎ 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
Trospium Chloride is oral at 3 DOSAGE FORMS & STRENGTHS Trospium chloride tablets USP are supplied as 20 mg tablets (brownish yellow, round, biconvex, film coated tablets, debossed with ‘E’ on one side and plain on other). 20 mg tablets., recorded as fda label in effect 2024-12-19 in the United States.
US prescribing information · 048b4bc7-c77e-40fc-9bfb-bb35c6a3f871 · read 2026-09-12
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 Trospium 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 a headache rate of 1.0% against 2.6% demonstrates absence of central nervous system effect — the cognitive effect this class produces has been shown to be unnoticeable to the patient and would never be volunteered
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 trospium is exempt from the class dementia association — a reasonable prediction from its charge, and one no observational dataset has separated out
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 "significant improvements in all primary and key secondary outcomes" tells a reader how much better the drug is than placebo
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 trial exposures describe real-world exposures for a drug whose absorption falls 70% to 80% if taken with a meal
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 Trospium 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.
Both pivotal trials published abstracts with no effect size at all
In plain words
The two trials that registered this drug enrolled 523 and 601 patients. Both met their endpoints. Neither published abstract contains a single number describing how much better the drug was than placebo.
What was measured
Presence of any quantified treatment effect in the published abstracts of the two pivotal trials
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Zinner and colleagues randomised 523 patients at 51 sites to trospium 20 mg twice daily or placebo for 12 weeks, with change in average toilet voids and change in urge incontinence episodes per 24 hours as dual primary endpoints. The results section states that trospium "significantly decreased average frequency of toilet voids and urge incontinent episodes compared to placebo" and "significantly increased average volume per void" — with no means, no differences, no confidence intervals and no p-values. Staskin and colleagues randomised 601 subjects to trospium extended-release 60 mg once daily (298) or placebo (303), and reported that treatment "resulted in significant improvements over placebo in all primary and key secondary efficacy outcomes at weeks 1 through 12" — again with no effect size. Both abstracts do give adverse-event percentages to one decimal place. A reader can learn exactly how many patients got dry mouth and cannot learn how many fewer accidents they had.
Written into the record, not signed off as a reviewed claim
The brain-sparing claim is supported by the headache rate
In plain words
The reason to choose this drug is that it should not reach the brain. The evidence offered in its own pivotal trial is that 1.0% of patients reported headache against 2.6% on placebo.
What was measured
That a low spontaneous headache rate demonstrates absence of central nervous system effect — it demonstrates the absence of volunteered headache reports, and the pivotal cognitive literature in this class shows the relevant effect is not volunteered
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Staskin and colleagues report: "Central nervous system adverse events were rare (headache with trospium 1.0% vs placebo 2.6%)." Zinner and colleagues open by asserting that trospium is "an anticholinergic agent with predominantly peripheral nonselective antimuscarinic activity lacking central nervous system effects" — a statement in the purpose section, before any data. Headache is a poor proxy for central anticholinergic effect; it was lower on drug than on placebo, which if taken at face value would imply a protective effect that nobody claims. Meanwhile the Kay trial in this same file showed that a measurable anticholinergic memory impairment can be entirely invisible to the person experiencing it and would therefore never enter a spontaneous adverse-event table. The structural argument for trospium is genuinely strong — a permanent cationic charge does limit membrane crossing — and it has not been converted into a measured cognitive outcome.
Written into the record, not signed off as a reviewed claim
A high-fat meal removes 70% to 80% of the dose
In plain words
Taken with a fatty meal, this drug delivers between a fifth and a third of the exposure it delivers on an empty stomach. That is one of the largest food effects of any common oral medicine.
What was measured
Reduction in area under the curve and peak concentration with a high-fat meal against fasting administration
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The US label states that administration with a high-fat (50%) meal resulted in reduced absorption, with area under the curve and peak concentration values 70% to 80% lower than in the fasting state, and directs that dosing occur at least one hour before meals. The magnitude follows directly from the permanent positive charge: a cation is poorly absorbed across the gut wall at the best of times, and a fatty meal makes it worse. This is the cost side of the same structural property the drug is chosen for. It is also the property that makes real-world effectiveness likely to differ from trial effectiveness by more than usual, because trial participants take medicines on schedule and the schedule here is demanding.
Source
US prescribing information for trospium chloride, Clinical Pharmacology section (openFDA drug label endpoint)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
Cleared by the kidney by active secretion, not by any liver enzyme
In plain words
Most drugs in this class are broken down by liver enzymes and therefore interact with anything else those enzymes handle. Trospium is pumped out by the kidneys instead, which is why it has essentially no cytochrome drug interactions.
What was measured
Mean renal clearance against average glomerular filtration rate, establishing active tubular secretion
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The label reports mean renal clearance for trospium of 29.07 L/hour, approximately four-fold higher than average glomerular filtration rate, and identifies active tubular secretion as the major elimination route. Zinner and colleagues open their pivotal trial by noting the drug "has no known drug-drug interactions, an advantage for patients taking many medications." That advantage is real and it is structurally guaranteed rather than empirically hoped for: a permanently charged compound is a poor substrate for the lipophilic-substrate cytochromes. The corresponding cost is that renal function, not hepatic function, sets exposure — and renal function declines with age in exactly the population the drug is chosen for.
Source
US prescribing information for trospium chloride, Clinical Pharmacology section; Zinner N et al., J Urol 2004;171:2311-2315
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
The once-daily formulation more than halved the dry mouth rate
In plain words
On the pooled twice-daily data the label reports dry mouth in one patient in five. The once-daily extended-release trial reported it in fewer than one in eleven.
What was measured
Incidence of dry mouth and constipation against placebo, immediate-release pooled data versus the extended-release pivotal trial
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The US label reports dry mouth in 20.1% against 5.8% on placebo and constipation in 9.6%, drawn from the twice-daily immediate-release programme. Staskin and colleagues, testing the 60 mg once-daily extended-release formulation in 601 subjects, reported dry mouth in 8.7% against 3% and constipation in 9.4% against 1.3%, and stated that dry mouth "was elicited at the lowest reported rate in the oral antimuscarinic drug class." The pattern is the same one oxybutynin and tolterodine show: slowing release lowers the peak concentration and roughly halves the peripheral anticholinergic effects without changing the molecule. It is worth noting the two figures are not from the same study and the comparison is across programmes, not within one.
Written into the record, not signed off as a reviewed claim
The effect started within a week and held for twelve
In plain words
Both pivotal trials reported that the improvement appeared by the end of the first week and lasted the full twelve. Nocturnal frequency took four weeks.
What was measured
Time to onset and duration of the reported treatment effect in both pivotal trials
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Zinner and colleagues report that all effects occurred by week 1 and were sustained throughout the study, with nocturnal frequency decreasing significantly by week 4 and Incontinence Impact Questionnaire scores improving at week 12. Staskin and colleagues report significant improvements over placebo in all primary and key secondary outcomes at weeks 1 through 12. Time course is one of the few things these abstracts do report clearly, and it is informative: a receptor antagonist acting on a surface receptor with no intracellular step should work within days, and it does. What neither paper reports is the magnitude at any of those time points.
Source
Zinner N et al., J Urol 2004;171:2311-2315 (PMID 15126811); Staskin D et al., J Urol 2007;178:978-984 (PMID 17632131)
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
The class dementia association was never tested with this drug separated out
In plain words
The large studies linking bladder anticholinergics to dementia treat them as one group. If the charge argument is right, trospium should be the exception — and no dataset has been able to check.
What was measured
That trospium is exempt from the class dementia association because it does not enter the brain — a mechanistically reasonable prediction that no observational dataset has separated out and no trial has tested
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Coupland and colleagues reported an adjusted odds ratio of 1.65 (95% CI 1.56 to 1.75) for bladder antimuscarinic drugs as a single class in 58,769 dementia cases and 225,574 controls. Gray and colleagues reported an adjusted hazard ratio of 1.54 (1.21 to 1.96) above 1,095 total standardised daily doses of strong anticholinergics in 3,434 people followed a mean 7.3 years, with bladder antimuscarinics among the three commonest contributing classes. Neither analysis separated the one drug in that class whose pharmacology predicts it should behave differently. Trospium is also the least prescribed of the group, which makes such a separation statistically hard rather than merely unattempted. The result is a testable prediction that has gone untested for two decades: if central penetration drives the association, the quaternary compound should sit outside it.
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What is not here
8 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 was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
How this medicine reached us — 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 quaternary ammonium muscarinic antagonist whose permanent positive charge limits entry to the brain by physics rather than by receptor preference: its two pivotal 12-week placebo-controlled trials in 523 and 601 patients both met their dual primary endpoints, both published abstracts state the results as "significant" without a single effect size, and the central-nervous-system safety claim rests on a headache rate that was lower on drug (1.0%) than on placebo (2.6%).
Recorded evidence blocks (6)
Q1
18 registered trials of Trospium — at which phases?
"Because of COVID-19 Crisis"; 1 of 18 registered studies
Show the evidence
TrialNCT03709992
suspended; "Because of COVID-19 Crisis"
recorded 2026-09-01 · last checked 2026-09-04
Q3
Human studies of Trospium used Sanctura XR™ 60 mg — over how long?
Human studies of Trospium used "Sanctura XR™ 60 mg". ClinicalTrials.gov · 2026-09-01
2 recorded entries; human; also "Sanctura XR® 60 mg"
Show the evidence
human
NCT00863551
Sanctura XR™ 60 mg
NCT00986401
Sanctura XR® 60 mg
recorded 2026-09-01 · last checked 2026-09-04
Q4
Which 4 trials of Trospium posted no result?
Posted no result
4 of 4 completed trials
Registrations
NCT02831231, NCT02386072, NCT03602508 and NCT03572231
Completion dates
oldest 2016-10-28; newest 2020-03-30
Show the evidence
Trial
NCT02831231
2016-10-28
NCT02386072
2017-08-04
NCT03602508
2019-09-13
NCT03572231
2020-03-30
Q5
At the median, Trospium's trials enrolled 147.5 people — anything larger?
Median enrolment
147.5
Largest enrolment
5589
Registered trials counted
18
Q6
What do 61 spontaneous reports say about Trospium — 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.
Trospium appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 61 reaction mentions were counted: loss of personal independence in daily activities 9; general physical health deterioration 7; urinary incontinence 7; weight decreased 7. FAERS via Open Targets · CHEMBL1888176 · 2026-06-24
Show the evidence
loss of personal independence in daily activities
9
general physical health deterioration
7
urinary incontinence
7
weight decreased
7
constipation
7
urinary retention
5
4 more recorded rows
palpitations
5
dry mouth
5
tachycardia
5
anticholinergic syndrome
4
recorded 2026-06-24 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
ChEMBL 37 — CC BY-SA 3.0 Unported · ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 5 source rows
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