The FDA has approved the marketing of a 10% topical gel formulation of the muscarinic receptor antagonist oxybutynin chloride (Gelnique - Watson) for treatment of overactive bladder. Oxybutynin is also available for this indication as oral tablets, an oral syrup and a transdermal patch.

The FDA has recently approved intradetrusor injection of onabotulinumtoxinA (Botox – Allergan) for treatment of overactive bladder in patients who cannot tolerate or have an inadequate response to anticholinergic therapy. Botox is also approved by the FDA for use in detrusor overactivity associated with a neurologic condition such as multiple sclerosis or spinal cord injury, and for chronic migraine, upper limb spasticity, axillary hyperhidrosis, cervical dystonia, blepharospasm, strabismus, and cosmetic reduction of wrinkles.

Mirabegron (mir a beg’ ron; Myrbetriq [meer BEH trick] – Astellas), a beta-3 adrenergic agonist, has been approved by the FDA for the treatment of overactive bladder. It is the first beta-3 adrenergic agonist to be approved for any indication in the US. Mirabegron has been marketed in Japan since 2011. OnabotulinumtoxinA (Botox) was also recently approved by the FDA for treatment of overactive bladder and will be reviewed in a future issue.

In overactive bladder, involuntary bladder contractions due to detrusor overactivity result in urinary urgency, frequency, nocturia, and incontinence. The prevalence of the disorder increases with age. Nonpharmacologic treatment, including bladder training, urge suppression, pelvic floor muscle exercises, constipation management, modification of fluid intake, and avoidance of dietary irritants such as alcohol and caffeine, should be tried first.