Anticholinergic approved for treatment of OAB.(News)

The U.S. Food and Drug Administration has approved a muscarinic receptor antagonist for treating overactive bladder that is more selective to the muscarinic receptors in the bladder than some older drugs in this class.

Approved in November, solifenacin succinate was developed with the aim of reducing dry mouth and other bothersome anticholinergic side effects that can limit treatment with less specific drugs.

Solifenacin was approved for the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency. The agent is manufactured by Yamanouchi Pharmaceutical Co., Ltd., and will be marketed under the trade name Vesicare.

Compared with older anticholinergics approved for OAB, solifenacin is a more selective muscarinic receptor blocker, as is trospium chloride, Richard Bercik, M.D., director of the division of urogynecology and reconstructive surgery at Yale University, New Haven, said in an interview. Trospium chloride, marketed as Sanctura, was approved for the treatment of OAB last May.

None of the newer agents has proved to be more effective than oxybutynin, the first anticholinergic approved for OAB, in the 1970s, but the newer agents have fewer side effects, observed Dr. Bercik, who said he is not affiliated with Yamanouchi or manufacturers of other OAB drugs, nor an investigator in any solifenacin studies.

Approval of solifenacin was based on four 12-week trials of 3,027 patients, who were predominantly white and female (mean age 58 years) and who had OAB symptoms for at least 3 years, with 11.5-12.2 micturitions over 24 hours at baseline. At 12 weeks, the number of micturitions per 24 hours had dropped by a mean of 2.3 in patients on the 5-mg dosage and 2.7 in those on 10 mg. vs. 1.4 with placebo--statistically significant differences. Efficacy was similar among different age groups and among men and women.

Secondary end points--the number of incontinence episodes over 24 hours and the mean volume voided per micturition--also were significantly improved with both solifenacin doses.