THURSDAY, June 28 (HealthDay News) -- Myrbetriq (mirabegron) has been approved to treat adults with overactive bladder, a condition affecting some 33 million Americans, the U.S. Food and Drug Administration said Thursday in a news release.

The drug is designed to relax the bladder muscle as the bladder fills, minimizing the potential symptoms of needing to urinate too often, needing to urinate immediately or the involuntary leakage of urine, the agency said.

The drug's safety and effectiveness were evaluated in clinical studies involving 4,116 people with overactive bladder. The most common side effects were a rise in blood pressure, cold-like symptoms, urinary tract infection, constipation, fatigue, increased heart rate and abdominal pain.

Myrbetriq is marketed by Astellas Pharma US, based in Northbrook, Ill.

More information

The U.S. National Library of Medicine has more about overactive bladder.