The FDA has approved a new drug, Toviaz, to treat patients with overactive bladders, a disorder that causes frequent, uncontrollable urination. Toviaz (fesoterodine fumarate) is made by Schwarz Pharma and distributed by Pfizer Inc of New York.

An overactive bladder is caused when the bladder muscle contracts involuntarily. This may result in feelings of urgently having to go to the bathroom. Toviaz works by relaxing the smooth muscle tissue of the bladder to reduce urinary frequency and leakage of urine, the agency said in a statement. The FDA approved Toviaz based on two 12-week randomized placebo-controlled studies, involving a total of 554 patients. The studies found that he drug reduced urinary frequency, urge to urinate, and sudden incontinence. The drug is approved for adults only.

According to the FDA, common side effects include dry mouth and constipation. Less frequently reported side effects included dry eyes and trouble emptying the bladder. Toviaz shouldn't be used by patients who suffer from urinary or gastric retention, patients with uncontrolled, narrow-angle glaucoma, or patients with severe liver impairment.

The recommended starting dose is 4 mg, which can be increased to 8 mg if needed, based upon individual response and tolerability.

"Patients who suffer from overactive bladder face quality of life issues that can hamper their ability to enjoy life to its fullest," said George Benson, deputy director, Division of Reproductive and Urologic Products at the FDA's Center for Drug Evaluation and Research. "This new drug will provide an additional treatment option to help them manage problems with an overactive bladder."