tolterodin

Tolterodine, also known as tolterodin, is a prescription antimuscarinic medication used to treat symptoms of overactive bladder, including urgency, frequency, and urge incontinence. It works by blocking muscarinic receptors in the bladder, which reduces involuntary detrusor muscle contractions and helps control urinary urgency.

The drug acts mainly as a competitive antagonist of acetylcholine at muscarinic receptors. It has activity at several receptor subtypes but exerts clinically meaningful effects by reducing bladder smooth muscle activity. Tolterodine is commonly administered as an immediate‑release formulation or as an extended‑release preparation to provide steady symptom control with once‑daily dosing.

Pharmacokinetics and metabolism: Tolterodine is taken orally and is metabolized in the liver primarily by cytochrome P450 enzymes, including CYP2D6 and CYP3A4, to an active metabolite, 5-hydroxymethyl tolterodine. The presence of CYP2D6 genetic polymorphisms can influence drug exposure, and patients who are poor or ultra‑rapid metabolizers may experience different effects. Extended‑release formulations are designed to maintain more consistent plasma levels.

Indications and dosing: Tolterodine is indicated for adults with overactive bladder symptoms. Dosing varies by formulation: immediate‑release regimens commonly involve 2 mg taken twice daily, while extended‑release (Detrol LA) is typically 4 mg once daily, with adjustments for hepatic impairment or tolerability as advised by a clinician.

Contraindications and precautions: It should not be used in patients with urinary retention, gastric retention, or uncontrolled angle‑closure glaucoma. Caution is advised in individuals with severe hepatic impairment, gastrointestinal obstruction, or myasthenia gravis, and in the elderly due to anticholinergic effects. Use during pregnancy or lactation should be discussed with a healthcare provider.

Adverse effects and interactions: Common adverse effects include dry mouth, constipation, headache, and dizziness. Less common effects can include blurred vision and urinary retention. Drug interactions include strong inhibitors or inducers of CYP3A4 and other anticholinergic medications, which can alter tolterodine exposure.