Beta-3 Medications for Overactive Bladders


It’s estimated that overactive bladder (OAB) affects 33 million people in the United States alone. While there are several different treatment options for incontinence, a new type of drug is changing the way this condition is controlled.

In 2012, the Food and Drug Administration (FDA) approved the use of beta-3 adrenergic agonist medication mirabegron — also known as Myrbetriq™ —  to treat OAB.

Here’s a closer look at this new medication:

How does it work?

Mirabegron relaxes the detrusor smooth muscle of the bladder — the muscle fibers that cover the bladder and release urine when contracted — by activating proteins and enzymes, so the bladder can fill more and store urine more efficiently.

Is it effective?

Researchers conducted three clinical trials testing mirabegron, resulting in positive effects for people with OAB. Two double-blind randomized clinical trials were performed during a 12-week period with OAB patients showcasing symptoms of frequent urination (eight or more times in a 24-hour period) and urge for more than three months.

The first trial was done in the U.S. and Canada with 1,329 patients. The second trial was done in Europe and Australia with 1,987 patients. The third trial was a multinational study performed across the U.S., Canada, Europe, Australia, and South Africa with 2,452 individuals as part of a long-term study over a 12-month period.

Individuals who took the once-daily oral pill experienced fewer incontinence episodes and reduced need to urinate within 24 hours, compared to those who took a placebo.  Participants kept a diary with baseline assessments performed every few weeks during the trial, and one after the trial.

However, according to the journal European Urology, while patients will likely see some improvement, the symptoms won’t be completely gone. It’s also uncertain whether beta-3s will be a first or second line of treatment for OAB. Some urologists prefer to use anticholinergics — one of the more popular medications types — first.

Are there any dangers or negative reactions?

A very small percentage of the trial participants experienced negative reactions (less than two percent). The most reported adverse reactions included hypertension, throat and nasal inflammation, urinary tract infections and headache. Be aware that this drug can increase blood pressure, so monitor blood pressure carefully and talk with your doctor before taking it, especially if you have high blood pressure or a history of it. People with poorly managed high blood pressure should not take mirabegron.


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