The U.S. Food and Drug Administration today expanded the approved use of Botox (onabotulinumtoxinA) to treat adults with overactive bladder who cannot use or do not adequately respond to a class of medications known as anticholinergics.
Overactive bladder is a condition in which the bladder squeezes too often or squeezes without warning. Symptoms include leaking urine (urinary incontinence), feeling the sudden and urgent need to urinate, and frequent urination.
When Botox is injected into the bladder muscle, it causes the bladder to relax, increasing the bladder's storage capacity and reducing episodes of urinary incontinence. Injecting the bladder with Botox is performed using cystoscopy, a procedure that allows a doctor to visualize the interior of the bladder while Botox is being injected.
"Clinical studies have demonstrated Botox's ability to significantly reduce the frequency of urinary incontinence," said Hylton V. Joffe, M.D., director of the Division of Reproductive and Urologic Products in FDA's Center for Drug Evaluation and Research. "Today's approval provides an important additional treatment option for patients with overactive bladder, a condition that affects an estimated 33 million men and women in the United States."
Botox's safety and effectiveness for this new indication were established in two clinical trials of 1,105 patients with symptoms of overactive bladder. Patients were randomly assigned to receive injections of 100 units of Botox (20 injections of 5 units each) or placebo.
Results after 12 weeks showed that patients treated with Botox experienced urinary incontinence an average of 1.6 to 1.9 times less per day than patients treated with placebo. Botox-treated patients also needed to urinate on average 1.0 to 1.7 times less per day and expelled an average of about 30 milliliters more urine than those treated with placebo.
Treatment with Botox can be repeated when the benefits from the previous treatment have decreased, but there should be at least 12 weeks between treatments.
Common side effects reported during clinical trials included urinary tract infections, painful urination, and incomplete emptying of the bladder (urinary retention). Patients who develop urinary retention may need to use a catheter until the urinary retention resolves. Patients being treated for overactive bladder with Botox should not have a urinary tract infection and should take antibiotics before, during, and for a few days after Botox treatment to lower the chance of developing an infection from the procedure.
Botox is manufactured by Allergan Inc. based in Irvine, Calif.