A new use for Botox® (onabotulinumtoxin A, Allergan, Inc.) was approved by the U.S. Food and Drug Administration, providing an additional treatment option for people with MS or other neurologic disorders who experience urinary incontinence. In clinical trials involving 691 with MS or spinal cord injury, targeted injections of Botox into the bladder muscle were found to be beneficial and safe.
Background: Bladder dysfunction occurs when MS lesions block or delay transmission of nerve signals in areas of the central nervous system that control the bladder and urinary sphincter. The result in MS can be a “spastic” bladder that is unable to hold the normal amount of urine, or by a bladder that does not empty properly and retains some urine in it. Retaining urine can lead to complications such as repeated infections or kidney damage. Left untreated, bladder dysfunction also could cause emotional and personal hygiene problems that can interfere with normal activities of living and socialization.
Botox is a powerful neurotoxin that temporarily blocks connections between the nerves and muscles, resulting in short-term relaxation of the targeted muscle. Injections have been shown in clinical trials to relieve spasticity in individual muscles for three to nine months. In March 2010 the FDA approved Botox for treating upper limb spasticity in people with MS and other disorders.
Injection of the bladder muscle with Botox is performed using cystoscopy, a procedure that allows a doctor to visualize the interior of the bladder. Cystoscopy may require general anesthesia.
FDA Approval: The FDA approval for treating bladder spasticity was based on results of two double-blind, placebo-controlled studies, one of which was presented at the 2011 Annual Meeting of the American Urological Association (Abstract # 1104026). The two clinical studies involved 691 people with urinary incontinence resulting from MS or spinal cord injury. In both studies, the weekly frequency of incontinence episodes showed statistically significant decreases in the Botox group compared with placebo.
According to the approved label, Botox is approved as a 200U dose for patients with urinary incontinence due to detrusor (the primary bladder muscle) overactivity associated with a neurologic condition. Patients should be considered for retreatment when the clinical effect of the previous treatment wears off.
The most common adverse events included urinary tract infection and urinary retention. According to the label, it is not known whether Botox is safe or effective in treating spasticity in children younger than 18. The medication carries a boxed warning that Botox injections may cause serious side effects that can be life threatening. These include problems swallowing, speaking or breathing, and the possibility that the toxin may spread to other areas of the body away from the injection site.
Read the FDA’s announcement here. If you have questions about the use of Botox for the treatment of spasticity, please consult your healthcare provider.
Botox is a registered trademark of Allergan, Inc.