tolterodine

Tolterodine is a competitive muscarinic receptor antagonist used to treat symptoms of an overactive bladder, including urge incontinence, urinary urgency, and frequency. It works by blocking muscarinic receptors in the detrusor muscle, particularly M3 receptors, which reduces involuntary detrusor contractions and increases bladder capacity.

The drug is taken by mouth in immediate-release and extended-release formulations. Immediate-release tablets are typically taken twice daily, while the extended-release capsule (Detrol LA) is taken once daily. Dosing is adjusted for age and hepatic function, and patients should follow prescribing information to minimize adverse effects.

Tolterodine is metabolized in the liver, primarily by the enzyme CYP2D6, to an active metabolite called 5-hydroxymethyl tolterodine. This metabolite contributes to the overall therapeutic effect. Because CYP2D6 activity varies among individuals, drug exposure can differ between poor and extensive metabolizers. Food does not have a major effect on overall exposure, but clinicians may consider individual patient factors when choosing a formulation.

Common adverse effects include dry mouth, constipation, and blurred vision. Dizziness, cognitive disturbance in older adults, and urinary retention can occur, especially in older patients or those with preexisting conditions. Tolterodine should be avoided in patients with hypersensitivity to the drug, urinary retention, gastric retention, or uncontrolled narrow-angle glaucoma. It interacts with other antimuscarinic drugs and with inhibitors of CYP2D6 or CYP3A4, which can increase tolterodine exposure and the risk of side effects.