Dose response with darifenacin, a novel once-daily M₃ selective receptor antagonist for the treatment of overactive bladder: results of a fixed dose study

This study evaluated the efficacy, tolerability, and safety of darifenacin, an M₃ selective receptor antagonist (M₃ SRA), in patients with overactive bladder (OAB). In a multicenter, double-blind, placebo-controlled dose-ranging study, 439 adult OAB patients (85.4% female) were randomized to darifenacin controlled-release tablets 7.5 mg (n = 108), 15 mg (n = 107) or 30 mg (n = 115) qd, or placebo (n = 109) for 12 weeks. Darifenacin significantly reduced the median number of incontinence episodes/week (−68.7, −76.5, and −77.3% from baseline at 7.5, 15, and 30 mg, respectively, vs −46% with placebo, all p< 0.01) and dose relatedly improved micturition frequency, frequency and severity of urgency, nocturia, and bladder capacity. Darifenacin was well tolerated. Adverse events were commonly mild to moderate dry mouth and constipation. There were no safety concerns. Darifenacin is effective and well tolerated in the treatment of OAB, with 7.5 and 15 mg doses offering flexibility of dosing for optimal treatment outcome.