Botox (onabotulinumtoxinA) injection isn't only good for making wrinkles smooth. It can now be used to treat a leaky bladder.

The U.S. Food and Drug Administration on Wednesday approved the drug to treat urinary incontinence in people with neurologic conditions such as spinal cord injury and multiple sclerosis who have an overactive bladder.

Botox is marketed in the United States by Allergan Inc., of Irvine, Calif.

When patients with these conditions have nerve damage, it can be difficult for them to retain their urine. These patients often need medication to relax the bladder, as well as catheters to empty the bladder, according to WebMD.

The Botox treatment consists of the drug being injected into the bladder, which results in relaxation of the bladder, an increase in its storage capacity and a decrease in urinary incontinence. The treatment for leaky bladder lasts about nine months.

Urinary incontinence associated with neurologic conditions can be difficult to manage, said George Benson, deputy director, Division of Reproductive and Urologic Products. Botox offers another treatment option for these patients.

The effectiveness of the Botox treatment for this type of incontinence was demonstrated in two clinical studies involving 691 patients, a FDA news release stated, and both studies showed statistically significant decreases in the weekly frequency of incontinence episodes in the Botox group when compared to a placebo.

The most common adverse reactions were urinary tract infection and urinary retention. Those who develop urinary retention after Botox treatment may require self-catheterization to empty the bladder, according to the FDA.