The FDA approved over-the-counter sales of the Oxytrol for Women patch on Jan. 25. as a treatment for overactive bladder (OAB). Oxytrol's active ingredient is oxybutynin, a drug that promotes relaxation of the bladder muscle. Oxytrol is the first medicine of its class to be approved for OTC sales.
The patch must be reapplied to the skin every four days. It is approved only for adult women ages 18 years and older. Men still need to get a prescription for Oxytrol, according to the FDA.
OAB, or urge incontinence, is typified by a sudden urge to urinate and frequent urination. According to Merck, overactive bladder affects more than 20 million American women. However, several published studies say the criteria for diagnosing OA isn't standardized and the severity of the symptoms vary widely.
The current market leader in OAB treatment is Pfizer's Detrol with sales of about $700 million annually.
Merck expects the patch will go on sale in the fall of 2013.