Mirabegron Safe and Effective for Overactive Bladder in Older Patients

By Will Boggs MD

NEW YORK - Mirabegron offers an alternative to antimuscarinic drugs for older patients with overactive bladder (OAB), according to pooled data from several clinical trials.

"Mirabegron is effective for community dwelling elderly and well tolerated for up to a year," Dr. Adrian Wagg from University of Alberta, Alberta, Canada told Reuters Health.

"OAB is a multifactorial disease in older people, who are likely to need multifactorial treatment," Dr. Wagg added.

Oral antimuscarinic drugs are the mainstay of pharmacotherapy for OAB, but their use can be associated with suboptimal efficacy, cognitive impairment, dry mouth, and constipation in older patients.

Mirabegron is the first beta3-adrenoreceptor agonist approved for the treatment of OAB, and it had a favorable safety profile in a one-year safety trial.

Dr. Wagg and colleagues pooled data from three 12-week studies of mirabegron and a one-year safety study to assess its efficacy and tolerability in 1189 OAB patients aged 65 years and older and 343 OAB patients aged 75 years and older.

Mirabegron 25 mg and 50 mg once-daily reduced the mean number of incontinence episodes to a greater extent than placebo in both age groups. By comparison, tolterodine 4 mg reduced episodes to a lesser extent than mirabegron.

Results were similar when mean micturition frequency was used as the endpoint, according to the March 14th Age and Ageing online report.

About half of the mirabegron patients 65 and older experienced treatment-emergent adverse events in the 12-week studies, and slightly more (65% of 65 and older, 68% of 75 and older) experienced such events over the course of a year.

In the 12-week trials, hypertension, nasopharyngitis, and urinary tract infection were among the most commonly reported adverse events in both age groups, but headache, dry mouth, and pain in the extremity were also reported.

In the comparative trials, dry mouth was three- to six-fold higher in the 65-and-older age group and four-fold higher in the 75-and-older age group with tolterodine than with mirabegron.

Moreover, adverse events leading to permanent discontinuation of study drug were more common with tolterodine than with either dose of mirabegron or placebo in both age groups.

"There remains a need for longer-term, prospective studies to assess the efficacy of mirabegron in older patients, either in the form of interventional or in the form of observational studies," the authors conclude.

Should mirabegron replace antimuscarinics for older people with OAB? "There's no evidence supporting this," Dr. Wagg said. "There are patients for whom mirabegron may be a more attractive choice, but we have no prospective data in older people."

SOURCE: https://bit.ly/1kZ5QdN

Age Ageing 2014.

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