Trospium
Overactive bladder agents
Overactive bladder agents
A quaternary antimuscarinic for overactive bladder. It barely enters the brain and is cleared by the kidneys, so central side effects are less likely.
Also called: Trospium chloride
Quick facts
- Group
- Overactive bladder agents
- Target
- Muscarinic M3 (and M2) receptors of the bladder (antagonist)
- Used for
- Overactive bladder
- Key effects
- Dry mouth · Constipation · Headache
- Monitor
- Urinary retention · Bowel habit · Kidney function
- ATC
- G04BD09
No doses: the clinician sets them by the current guideline.
Mechanism of action
No trospium-bound structure exists. The figure shows tiotropium, another quaternary muscarinic antagonist, in the acetylcholine pocket of the rat M3 receptor, the subtype that contracts the bladder; the pocket is nearly identical in the human receptor.
Trospium blocks muscarinic receptors in the detrusor muscle of the bladder, so acetylcholine released by parasympathetic nerves causes weaker involuntary contractions; urgency, frequency and urge incontinence improve. As a quaternary ammonium compound it is charged, crosses the blood-brain barrier poorly and is less likely to cause confusion than tertiary agents such as oxybutynin.
- Trospium blocks muscarinic receptors in the detrusor
- Weaker involuntary bladder contractions: less urgency
- Quaternary charge: little entry into the brain
- Renal tubular secretion: caution in kidney disease
Indications
- Overactive bladder with urge incontinence, urgency and frequency Overactive bladder and urge incontinence →
Adverse effects
Common
- Dry mouth (the most common)
- Constipation
- Headache
- Dry eyes and nose
Contraindications
- Urinary retention
- Gastric retention
- Uncontrolled narrow-angle glaucoma
- Hypersensitivity to trospium
Key interactions
- Drugs actively secreted by the kidney
- May compete for tubular secretion and change levels of either drug
- Metformin
- Lower trospium exposure
- Other anticholinergic drugs
- Added dry mouth, constipation and urinary retention
What is monitored
- Urinary retention and post-void residual if obstruction is suspected
- Bowel habit
- Kidney function
Administration and safety
- Given with water on an empty stomach, at least one hour before meals
- Extended-release and immediate-release forms are different products
Pregnancy and breastfeeding
Human data are lacking; it is used only if the benefit outweighs the risk.
Nursing care
- Asks about difficulty passing urine and a weak stream
- Watches for constipation and dry mouth and suggests mouth care
- Reports swelling of the face, lips or tongue at once
- Checks kidney function before and during treatment
Pharmacokinetics
- Absorption
- Incompletely absorbed by mouth (a charged quaternary amine); taken on an empty stomach
- Elimination
- Mainly by the kidneys, partly by active tubular secretion; exposure rises in severe renal impairment
Test yourself
Think of the answer, then tap the question to see it.
Why does trospium cause fewer central side effects than oxybutynin?
It is a quaternary amine that crosses the blood-brain barrier poorly.
How is trospium mainly eliminated?
By the kidneys, partly through active tubular secretion.
What is one contraindication of trospium?
Urinary retention, gastric retention or uncontrolled narrow-angle glaucoma.
Connections
← Back to the class: Overactive bladder agents
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - TROSPIUM CHLORIDE tablet (DailyMed (U.S. National Library of Medicine), 2026); Trospium: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.