U.S. Food and Drug Administration approved Allergan's Botox injection for treating patients who have bladder control problems arising from spinal cord injury or multiple sclerosis (MS).

Patients with such neurological problems can now avail of the popular wrinkle treatment to keep a leaky bladder in check.

An overactive or leaky bladder is caused by uncontrollable contractions of the bladder which results in frequent urination, urgent need to urinate and inability to control urination. A Botox injection treats the problem by relaxing the bladder muscles and allowing more space for urine storage. The effects could last for about nine months.

Around 60 to 80 percent of patients with multiple sclerosis or spinal cord injury experience some form of bladder problems, according to global pharmaceutical company Allergan. 350,000 of such patients are from the United States.

This approval of Botox is an important milestone in Allergan's commitment to develop and make available novel treatment options for urologists and their patients, Scott Whitcup, Allergan's chief scientific officer and executive vice president for research and development, said in a statement.

The company is also trying to gain approval to market Botox as a treatment for idiopathic (of unknown cause) overactive bladder, a more common condition among patients with bladder control problems.

 This approval is positive as it may bode well for the eventual approval of Botox in idiopathic overactive bladder, Seamus Fernandez, an analyst at Leerink Swann & Co., pointed out in a research note.

Sales of the drug for incontinence in people with MS and spinal cord injuries may reach $40 million in 2017, predicted Fernandez. He also said that if the FDA approves Botox for idiopathic overactive bladder it may boost drug sales by $210 million in 2017. Allergan plans to seek FDA clearance for that use next year, Fernandez added.

Botox is a purified form a botulinum, one of the most toxic substances in the world. It works by blocking the connections between nerves and muscle, temporarily paralyzing the muscle.

Besides removing wrinkles from the forehead, Botox is already approved for treating muscle spasms, migraine and eyelid twitching.

Allergan shares closed up 3 percent at $77.90 at 4 p.m. in New York Stock Exchange composite trading. The shares have climbed 13 percent this year, reports Bloomberg.