The U.S. Food and Drug Administration has approved the new drug Vesicare (solifenacin succinate) to treat symptoms of overactive bladder, the drug’s makers said.

Overactive bladder (OAB) is a condition that causes the bladder muscle to contract while the organ is filling, rather than when it is full. People with the condition feel the urge to urinate more frequently, often without warning. OAB affects up to 20 million men and women in the United States, reported the drug’s makers, GlaxoSmithKline and Japan’s Yamanouchi Pharmaceutical Co.

Approval of Vesicare followed four 12-week trials involving more than 3,000 people with OAB symptoms, including the urge to urinate more frequently and the accidental leakage of urine, the companies said in a prepared statement. The most common side effects were dry mouth, constipation, and blurred vision.