The pharmacokinetic profile of solifenacin succinate (YM905; Vesicare), a new once-daily bladder-selective muscarinic receptor antagonist, was examined in 2 controlled trials of healthy young men. A single-dose study evaluated 5-, 10-, 20-, 40-, 60-, 80-, and 100-mg doses. A multidose study evaluated 5-, 10-, 20-, and 30-mg doses. In the single-dose study, mean time to maximal concentration and elimination half-life ranged from 3.3 to 4.8 and from 40.2 to 57.6 hours, respectively; in the multidose study, the corresponding ranges were 2.9 to 5.8 and 45.0 to 64.8. Plasma concentration and area under the curve increased linearly with single doses in both trials. At steady state, a less regular increase was seen, with higher values in the 20-mg group than in the 30-mg group. All doses in the single-dose study were well tolerated. At steady state, only the 30-mg dose was not well tolerated. The most commonly reported adverse events were dry mouth, blurred vision, and headache. Solifenacin 5 and 10 mg, either as single doses or at steady state, had minimal effect on salivary flow, visual nearpoint, and the incidence of adverse events. Solifenacin was well tolerated up to single doses of 100 mg and after multiple doses of 20 mg. Its pharmacokinetic profile makes it suitable for qd administration.