Trospium for Overactive Bladder Treatment
Trospium chloride is recommended at a dosage of 60 mg extended-release capsule once daily in the morning on an empty stomach, at least one hour before a meal, for the treatment of overactive bladder symptoms. 1
Indications and Mechanism
Trospium chloride is a muscarinic antagonist indicated for the treatment of overactive bladder (OAB) with symptoms of:
- Urge urinary incontinence
- Urgency
- Urinary frequency
As an anticholinergic agent with predominantly peripheral nonselective antimuscarinic activity, trospium has several unique properties:
- Quaternary ammonium compound with minimal central nervous system penetration
- Not metabolized by the cytochrome P450 system (lower risk of drug interactions)
- Primarily excreted unchanged in urine as the active parent compound 2
Dosing Options
Extended-Release Formulation (Preferred):
- 60 mg once daily in the morning
- Take with water on an empty stomach (at least 1 hour before meals)
- Onset of action as early as 1 week 3
Immediate-Release Formulation:
Clinical Efficacy
Trospium has demonstrated significant improvements in key OAB symptoms:
- Decreased urinary frequency
- Reduced urgency severity
- Decreased urge urinary incontinence episodes
- Increased volume per void
- Reduced daytime and nighttime frequency 5
These effects begin within the first week of treatment and are sustained throughout the treatment period of 12 weeks 4, 5.
Special Populations and Dosage Adjustments
- Renal Impairment: Not recommended for patients with severe renal impairment (creatinine clearance <30 mL/min) 1, 6
- Elderly Patients: No specific dose adjustment required, but monitor closely due to potential for anticholinergic effects
- Hepatic Impairment: No specific dose adjustment required based on available data
Contraindications
Trospium is contraindicated in patients with:
- Urinary retention
- Gastric retention
- Uncontrolled narrow-angle glaucoma
- Known hypersensitivity to the drug or its ingredients 1
Common Adverse Effects
- Dry mouth (8.7% with once-daily formulation vs. 3% with placebo) 3
- Constipation (9.4% with once-daily formulation vs. 1.3% with placebo) 3
- Central nervous system effects are rare due to minimal blood-brain barrier penetration 2, 3
Treatment Algorithm for OAB
According to AUA/SUFU guidelines 7:
- First-line: Behavioral therapies (bladder training, pelvic floor muscle exercises, fluid management)
- Second-line: Pharmacologic management
- Antimuscarinic agents (including trospium)
- β3-adrenoceptor agonists (mirabegron)
- Combination therapy: For patients refractory to monotherapy, consider combining an antimuscarinic with a β3-adrenoceptor agonist 7
- Third-line: For refractory cases
- Intradetrusor onabotulinumtoxinA
- Peripheral tibial nerve stimulation (PTNS)
- Sacral neuromodulation (SNS)
Clinical Pearls and Caveats
- Drug Interactions: Trospium has minimal drug-drug interactions due to lack of cytochrome P450 metabolism 2
- CNS Effects: Lower risk of cognitive effects compared to other antimuscarinics that cross the blood-brain barrier 2
- Administration: Taking with food significantly decreases bioavailability (to 26% of fasting levels) 6
- Monitoring: Assess for urinary retention in patients with bladder outflow obstruction 1
- Treatment Duration: Persistent therapy is required as effects are maintained only as long as treatment continues 7
- Treatment Success: Evaluate efficacy after 4-8 weeks; consider alternative therapy if inadequate symptom control 7