Health regulators approved Merck & Co's nonprescription version of Oxytrol to treat overactive bladder in women ages 18 and older, the agency said on Friday.
The U.S. Food and Drug Administration said the over-the-counter version of Oxytrol would be available for women only and that the drug remained available to men by prescription.
Overactive bladder, which affects an estimated 33 million Americans, is a condition in which the bladder squeezes too often or without warning. Symptoms include leaking urine, feeling a sudden and urgent need to urinate, and frequent urination.
Oxytrol for Women is a patch that contains oxybutynin, a medicine that helps relax the bladder muscle, and is designed to be applied to the skin every four days, the FDA said.
Oxybutynin belongs to a class of drugs known as anticholinergics. Pfizer Inc's Detrol is the market leader in the class with annual sales of about $700 million.
Oxytrol will be the first drug in the class to be sold over the counter. Merck licensed exclusive rights to sell OTC Oxytrol from Actavis Inc, the generic drugmaker formerly known as Watson Pharmaceuticals.
Merck said it expected the OTC patch to be available in the fall.
The FDA decided to approve the OTC version of the Merck drug, based on the results of nine studies of women that demonstrated that consumers can understand the information on the label, properly determine whether the product is right for them, and use the drug appropriately, the agency said.
Last week, the FDA approved the popular wrinkle treatment Botox from Allergan Inc to treat overactive bladder in people who cannot tolerate drugs from the class to which Oxytrol belongs or are not helped by these medications.
Merck shares rose 3 cents to $43.03 on the New York Stock Exchange.
(Reporting by Bill Berkrot; Editing by Lisa Von Ahn and Jan Paschal)