The study included a three- or five-week screening period, followed by a 12-week treatment period during which patients received either one of three doses of dexmecamylamine or placebo twice daily, randomized in a ratio of 2:1:1:1 (placebo, low dose, mid dose, high dose), with a two-week follow-up period. A total of 768 subjects with overactive bladder were randomized into the double-blind treatment period of the study.