Annals of Long Term Care

On June 28, 2012, the FDA approved Myrbetriq (mirabegron) to treat overactive bladder, a common condition among older adults in which the bladder muscle cannot be controlled, causing excessive urination and involuntary urinary leakage. The drug is an extended-release tablet taken by mouth daily to help improve the storage capacity of the bladder by relaxing it during filling. 

“An estimated 33 million Americans suffer from overactive bladder, which is uncomfortable, disrupting, and potentially serious,” said Victoria Kusiak, MD, deputy director, Office of Drug Evaluation III, FDA Center for Drug Evaluation and Research, in a press release.

The safety and efficacy of Myrbetriq, a beta-3 adrenergic agonist, were determined in three double-blind, placebo-controlled, multicenter clinical trials involving 4116 patients with overactive bladder. Study participants were randomly assigned to Myrbetriq at 25-mg, 50-mg, or 100-mg once-daily doses or to placebo for 12 weeks. Results showed that frequency of urination and of wetting accidents in a 24-hour period were significantly reduced in patients taking the 25-mg and 50-mg dose of Myrbetriq. Additionally, those taking the 50-mg dose expelled a greater amount of urine, which demonstrated the drug’s ability to improve bladder storage capacity. The average bladder can hold 350 mL of urine. Most people with normal bladder function feel the urge to urinate when the bladder fills up to 200 mL. 

Myrbetriq is contraindicated in patients with severe uncontrolled hypertension, end-stage kidney disease, or severe liver impairment. Common side effects included increase in blood pressure, symptoms mimicking the common cold, urinary tract infections, constipation, tachycardia, and abdominal pain. Access Myrbetriq’s full prescribing information at http://bit.ly/Myrbetriq_PI.