Prescription ·Strong evidence ·Reviewed May 2026
Tolterodine is an antimuscarinic used for overactive bladder with urgency, frequency, and urge incontinence. It reduces detrusor overactivity but can cause dry mouth, constipation, urinary retention, blurred vision, cognitive effects in susceptible patients, and QT concerns in patients with risk factors or interacting drugs.
The bottom line
Evidence rating strong. Most-documented uses: reduced urinary urgency, reduced urinary frequency, reduced urge incontinence. 3 sources indexed (2001–2026), with 4 interaction records on file.
Core mechanism
Tolterodine and its active 5-hydroxymethyl metabolite competitively antagonize muscarinic receptors in the bladder. Reduced acetylcholine-mediated detrusor contraction increases bladder capacity and decreases urgency. Metabolism depends on CYP2D6 and CYP3A4, so poor metabolizer status and potent CYP3A4 inhibitors can increase exposure.1,3
May be taken with or without food. Swallow extended-release capsules whole.3
Antimuscarinic slowing of gastrointestinal transit may increase mucosal injury risk from solid potassium products.
Recommendation: Use potassium only under clinician direction; report abdominal pain, vomiting, bleeding, or severe constipation.
High-dose quercetin may inhibit CYP3A4 or transporters, potentially increasing tolterodine exposure in some patients.
Recommendation: Monitor dry mouth, constipation, urinary retention, blurred vision, palpitations, or dizziness after changes in quercetin use.
St. John's Wort may induce CYP3A4 and reduce tolterodine exposure, lowering symptom control.
Recommendation: Avoid starting or stopping without monitoring overactive bladder symptoms and adverse effects.
Melatonin may add to tolterodine-associated somnolence or dizziness.
Recommendation: Use cautiously in older adults or fall-prone patients.
Numbered references. Citations throughout the page link here.
Trials showed reduced incontinence and micturition frequency with once-daily tolterodine ER.
Guideline recommends shared decision-making and monitoring of antimuscarinic adverse effects.
Labeling describes 4 mg extended-release dosing, lower-dose situations, contraindications, QT warning, and potent CYP3A4 inhibitor precautions.
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