Japan-based Astellas Pharma has announced that Vesicare (solifenacin succinate), indicated for the treatment of the overactive bladder (OAB), will be available in the Japanese market this month in 2.5 mg and 5 mg tablets.

Vesicare is the first drug approved for OAB in Japan. It relieves the associated symptoms by blocking the detrusor muscle's muscarinic receptors. The medication has already been marketed in around 20 countries in Europe and the U.S.

OAB is caused by excessive contraction of the detrusor muscle, the smooth muscle that surrounds the bladder; associated symptoms include increased urinary frequency, urgency and urge incontinence. In Japan, the number of OAB patients is estimated to be 8.1 million - nearly 12 percent of men and women aged 40 years or older. These symptoms caused significant inconvenience and distress in patients' daily lives.