Botox for Overactive Bladder Approved by FDA

On January 18, 2013, the FDA announced its approval of onabotulinumtoxinA (Botox) for the treatment of overactive bladder in adults who cannot use or who do not respond adequately to anticholinergic medications.¹ The injection of onabotulinumtoxinA into the bladder muscle helps relax the bladder, which minimizes “abnormal” contractions of the detrusor muscle and the urethral muscle that cause urinary incontinence and urinary urgency. The interior of the bladder, where onabotulinumtoxinA is injected, is visualized through the use of cystoscopy.
   
“Clinical studies have demonstrated Botox’s ability to significantly reduce the frequency of urinary incontinence,” said Hylton V. Joffe, MD, director of the Division of Reproductive and Urologic Products in the FDA’s Center for Drug Evaluation and Research.¹ “[This] approval provides an important additional treatment option for patients with overactive bladder, a condition that affects an estimated 33 million mean and women in the United States.”
   
The approval of onabotulinumtoxinA for overactive bladder was based on the results of 2 clinical trials of more than 1100 patients with symptoms of the condition.² Patients were assigned to either placebo or 100 units of Botox (20 injections of 5 units each) or placebo. After 12 weeks, patients in the treatment group, compared with those in the placebo group, had an average of 1.6 to 1.9 times fewer episodes of urinary incontinence per day and had and needed to urinate an average of 1.0 to 1.7 fewer times per day. In addition, patients in the treatment group eliminated 30 milliliters more urine than patients in the placebo group.
   
The effects of treatment with onabotulinumtoxinA can last between 135 and 168 days, compared with 88 to 92 days in patients in the placebo group. Treatment with onabotulinumtoxinA can be repeated after the benefits of the previous treatment have decreased or worn off, but a minimum of 12 weeks should pass between treatments. In the 2 clinical trials, complete continence was achieved in 22.9% and 31.4% of patients in the treatment groups, compared with 6.5% and 10.3% of patients in the placebo groups.2 Also, candidates for treatment with onabotulinumtoxinA should be free of any urinary tract infection and should take antibiotics before, during, and after treatment (a few days) to minimize the risk of the development of a cystoscopy-related urinary tract infection.
   
The adverse effects most commonly reported were urinary tract infections, dysuria, and urinary retention, which may require management with a catheter until the urinary retention resolves.

Pertinent Points:
- Cystoscopy-directed injection of onabotulinumtoxinA has been approved by the FDA to treat overactive bladder in patients who inadequately respond to anticholinergics or who cannot use anticholinergics.
- Antibiotic prophylaxis before, during, and after treatment is recommended.
- The most common adverse effects of treatment are urinary tract infections, dysuria, and urinary retention.

References:

1. U.S. Food and Drug Administration. FDA approves Botox to treat overactive bladder. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm336101.htm. Accessed February 1, 2013.
2. Botox [package insert]. Irvine, Calif: Allergan Inc; 2013.