Botox® Approved for Urinary Incontinence

On August 24, 2011, Allergan, Inc. announced that the United States Food and Drug Administration (FDA) approved Botox® (onabotulinumtoxinA) injection for the treatment of urinary incontinence. Specifically, the approval is for adults who experience “detrusor over-activity” resulting from a neurological condition, such as multiple sclerosis (MS) and who either do not respond adequately or are intolerant of anticholinergic medications.

In Allergan’s two Phase III trials, 200 units of Botox were injected directly into the bladder muscle. Botox works by temporarily blocking the nerve impulses that cause the bladder to contract excessively. At baseline (when the trial began) the MS patients averaged over 30 episodes of urinary leakage or incontinence per week. In these trials, those study participants treated with Botox experienced 20 fewer episodes of urinary leakage (or incontinence) per week. This is compared to those on placebo, who experienced about 11 fewer episodes. The effects of one Botox treatment typically lasted between 10 and 11 months for study participants (42 to 48 weeks).

These two pivotal Phase III trials involved 691 patients, 381 of whom had MS. Participants either did not respond sufficiently to anticholinergic medications or were unable to tolerate them. Patients were randomized to receive either active Botox treatment or a placebo. The procedure involves a physician administering an injection across the bladder muscle. A cystoscope is used, which is a special tube with a lens to see inside the bladder. If requested by the patient, local anesthesia was given.

Urinary incontinence, which is the frequent and unexpected loss of control to hold urine, is a common problem for many individuals with neurological conditions such as MS or spinal cord injury. When damage occurs along the spinal cord – such as lesions in individuals with MS – the nerves may not be able to send the appropriate signals to the bladder. This can cause the bladder muscles to involuntarily contract, building pressure within the bladder, and reducing the amount of urine that may be held. This is known as “detrusor over-activity,” or “over-active bladder.” As a result, people perceived an urgent need to urinate, even during the night.

Urinary incontinence is estimated to affect 340,000 individuals in the United States . Unfortunately, this can be an embarrassing topic for people who suffer from this condition, and many times the condition may go undiagnosed and untreated.

For those who do seek treatment, anticholinergic medications are often prescribed. These can include drugs such as Enablex®, Vesicare®, and Detrol®, among others. They work by relaxing the bladder muscle, reducing involuntary contractions. On average, these drugs may result in five fewer trips to the bathroom and four fewer leakage accidents over the course of one week. Medications for urinary incontinence are often given orally. While these medications work for a number of individuals, some may have difficulty with the side effects, while others may not achieve the desired results. Surgery is sometimes an option when these medications fail.

The approval of Botox injections for the treatment of urinary incontinence provides a new, long-term option for adults with neurological conditions who do not benefit from or cannot tolerate anticholinergic medications. For individuals who experience a substantial reduction in episodes of urine leakage, this treatment may lead to a significantly improved quality of life. MSAA recommends that MS patients with an overactive bladder discuss this new treatment with their doctors. Their doctors are in the best position to judge the appropriateness of Botox bladder injection.

The most common side effects of the Botox treatments for urinary incontinence were urinary tract infection and urinary retention. Other side effects, such as hematuria (bleeding), fatigue, constipation, and muscle weakness, along with others, each occurred in an average of 4 to 6 percent of patients.

Botox was first approved 20 years ago by the FDA for the treatment of certain eye-muscle disorders. Since that time it has also been approved by the FDA to treat other disorders, which include a condition causing abnormal head position and neck pain; chronic migraine; symptoms of severe underarm sweating; and the cosmetic use of temporarily improving the appearance of severe frown lines between the eyebrows. Botox injections were approved for upper extremity spasticity in March 2010; this is a condition often experienced by individuals with neurological conditions, including MS.

For more information, please visit, which gives information on the different approved uses for Botox. Urinary incontinence will soon be added to the listing on this website. Individuals with questions may also check with their doctor, or speak with one of MSAA’s Helpline consultants at (800) 532-7667.

Written by Susan Wells Courtney, MSAA Senior Writer
Reviewed by Jack Burks, MD, MSAA Chief Medical Officer