Trospium

Q: What is Trospium used for?

Trospium is evaluated for the following indications with varying evidence strength: Overactive bladder (evidence tier B), Urge urinary incontinence (evidence tier B), Frequent urination without prior evaluation (evidence tier F). See the full indication matrix with dosing and citations above on this page.

Q: What are the side effects of Trospium?

Common side effects of Trospium (≥ 1 in 100): Dry mouth (10–22%), Constipation (7–10%), Dyspepsia, Headache, Dry eyes. See the Safety section for uncommon and serious reactions.

Q: Is Trospium safe during pregnancy?

FDA category C. FDA Category C. No controlled human pregnancy studies. AEMPS does not recommend use in pregnancy unless the expected benefit outweighs the risk. The quaternary structure reduces placental transfer compared with tertiary antimuscarinics, but clinical data are limited.

Q: Is Trospium compatible with breastfeeding?

Use with caution. Hale L3. The quaternary structure minimises milk transfer: e-Lactancia rates the risk as low for short-term use. Monitor infant sucking and tolerance.

Q: Who should not take Trospium?

Trospium is contraindicated in: Hypersensitivity to trospium; Urinary retention; Gastric retention; Uncontrolled narrow-angle glaucoma; Myasthenia gravis. Full list in the Safety section.

AEMPS

Quaternary ammonium muscarinic blocker for overactive bladder

ATC code: G04BD09 (Trospium)

Brand names

Sanctura XR, Sanctura

Mechanism of action

Quaternary amine: the molecule carries a permanent positive charge and barely crosses the blood-brain barrier. This distinguishes it from tertiary amines (solifenacin, tolterodine, fesoterodine, oxybutynin) and almost eliminates central side effects: confusion, memory impairment, somnolence. Competitive antagonist of M1–M5 muscarinic receptors without marked selectivity. Low bioavailability (around 10%), not CYP-metabolised, minimal drug interactions. Take on an empty stomach an hour before food or two hours after: food halves the bioavailability.

Indications

Overactive bladder

Second line

Trospium is a second-line muscarinic blocker for overactive bladder and a preferred choice in older patients. NG123 (2024) explicitly notes: the quaternary amine does not cross the blood-brain barrier and is less likely to cause confusion, memory impairment and somnolence than tertiary antimuscarinics (solifenacin, tolterodine, oxybutynin). AEMPS approves 20 mg twice daily on an empty stomach (or 60 mg SR once daily). With renal impairment (CrCl <30 mL/min) the dose is halved.

Sources

Urge urinary incontinence

Second line

AEMPS approves trospium for urge urinary incontinence in adults after behavioural therapy fails. The Madhuvrata meta-analysis (Cochrane 2012) showed trospium efficacy comparable to tertiary antimuscarinics with fewer cognitive side effects. In older patients with cognitive impairment (mild cognitive impairment, early dementia), AEU 2023 and AGS Beers 2023 position trospium as the muscarinic blocker of choice due to minimal blood-brain barrier penetration.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Frequent urination without prior evaluation

Not recommended

Trospium is prescribed for «frequent toilet visits» without proper diagnostic workup, especially in Russia under the Spasmex brand. Increased urinary frequency is a symptom that may mean UTI, diabetes mellitus, BPH, neurological disease, or excess caffeine and fluid intake. Before any muscarinic blocker, the patient needs a bladder ultrasound with post-void residual, urinalysis and a 3-day voiding diary. In men over 50 with untreated BPH, trospium raises the risk of acute urinary retention. If trospium was prescribed without a bladder ultrasound or urinalysis, consider seeking a second opinion.

Sources

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Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA

Spanish Medicines Information Centre (CIMA)

Label dated: 02/28/2025

FDA / DailyMed

FDA — DailyMed Drug Labels

Label dated: 04/23/2026

Safety

Contraindications

Hypersensitivity to trospium
Urinary retention
Gastric retention
Uncontrolled narrow-angle glaucoma
Myasthenia gravis
Severe ulcerative colitis and toxic megacolon
Tachyarrhythmias

Serious adverse effects

Acute urinary retention
Tachycardia
Acute angle-closure glaucoma
Angio-oedema

Common adverse effects

Dry mouth (10–22%)
Constipation (7–10%)
Dyspepsia
Headache
Dry eyes

PregnancyFDA C

FDA Category C. No controlled human pregnancy studies. AEMPS does not recommend use in pregnancy unless the expected benefit outweighs the risk. The quaternary structure reduces placental transfer compared with tertiary antimuscarinics, but clinical data are limited.

Breastfeeding

Use with caution. Hale L3. The quaternary structure minimises milk transfer: e-Lactancia rates the risk as low for short-term use. Monitor infant sucking and tolerance.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Trospium used for?

Trospium is evaluated for the following indications with varying evidence strength: Overactive bladder (evidence tier B), Urge urinary incontinence (evidence tier B), Frequent urination without prior evaluation (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Trospium?

Common side effects of Trospium (≥ 1 in 100): Dry mouth (10–22%), Constipation (7–10%), Dyspepsia, Headache, Dry eyes. See the Safety section for uncommon and serious reactions.

Is Trospium safe during pregnancy?

FDA category C. FDA Category C. No controlled human pregnancy studies. AEMPS does not recommend use in pregnancy unless the expected benefit outweighs the risk. The quaternary structure reduces placental transfer compared with tertiary antimuscarinics, but clinical data are limited.

Is Trospium compatible with breastfeeding?

Use with caution. Hale L3. The quaternary structure minimises milk transfer: e-Lactancia rates the risk as low for short-term use. Monitor infant sucking and tolerance.

Who should not take Trospium?

Trospium is contraindicated in: Hypersensitivity to trospium; Urinary retention; Gastric retention; Uncontrolled narrow-angle glaucoma; Myasthenia gravis. Full list in the Safety section.

Mechanism of action

Indications

Overactive bladder

Second line

Sources

Urge urinary incontinence

Second line

Sources

Safety

Contraindications

Hypersensitivity to trospium
Urinary retention
Gastric retention
Uncontrolled narrow-angle glaucoma
Myasthenia gravis
Severe ulcerative colitis and toxic megacolon
Tachyarrhythmias

Serious adverse effects

Acute urinary retention
Tachycardia
Acute angle-closure glaucoma
Angio-oedema

Common adverse effects

Dry mouth (10–22%)
Constipation (7–10%)
Dyspepsia
Headache
Dry eyes

PregnancyFDA C

Breastfeeding

Use with caution. Hale L3. The quaternary structure minimises milk transfer: e-Lactancia rates the risk as low for short-term use. Monitor infant sucking and tolerance.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Trospium used for?

What are the side effects of Trospium?

Common side effects of Trospium (≥ 1 in 100): Dry mouth (10–22%), Constipation (7–10%), Dyspepsia, Headache, Dry eyes. See the Safety section for uncommon and serious reactions.

Is Trospium safe during pregnancy?

Is Trospium compatible with breastfeeding?

Use with caution. Hale L3. The quaternary structure minimises milk transfer: e-Lactancia rates the risk as low for short-term use. Monitor infant sucking and tolerance.

Who should not take Trospium?

Trospium is contraindicated in: Hypersensitivity to trospium; Urinary retention; Gastric retention; Uncontrolled narrow-angle glaucoma; Myasthenia gravis. Full list in the Safety section.