A new drug called mirabegron (Myrbetriq) has been granted FDA approval to treat overactive bladder in adults, a condition in which the bladder muscle cannot be controlled, squeezes too often or squeezes without warning. Symptoms of overactive bladder include the need to urinate too often (urinary frequency), the need to urinate immediately (urinary urgency) and the involuntary leakage of urine as a result of the need to urinate immediately (urge urinary incontinence). “An estimated 33 million Americans suffer from overactive bladder, which is uncomfortable, disrupting and potentially serious,” said Victoria Kusiak, MD, deputy director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research. “Today’s approval provides a new treatment option for patients with this debilitating condition.”
An extended-release tablet taken once daily, Myrbetriq improves the storage capacity of the bladder by relaxing the bladder muscle during filling. Myrbetriq’s safety and efficacy were demonstrated in three double-blind, placebo-controlled, multicenter clinical trials. According to the FDA, a total of 4,116 patients with overactive bladder were randomly assigned to take Myrbetriq at doses of 25 milligrams, 50 mg or 100 mg or a placebo once daily for 12 weeks. Results showed that Myrbetriq 25 mg and 50 mg effectively reduced the number of times a patient urinated and the number of times a patient had wetting accidents during a 24-hour period. Patients taking Myrbetriq 50 mg also expelled a greater amount of urine, demonstrating the drug’s effectiveness in improving the storage capacity of the bladder. The most common side effects observed in the trials were increased blood pressure, common cold-like symptoms (nasopharyngitis), urinary tract infection, constipation, fatigue, elevated heart rate (tachycardia) and abdominal pain. Myrbetriq is not recommended for use in those with severe uncontrolled high blood pressure, end stage kidney disease or severe liver impairment.