Comparison of overactive bladder treatments published in Mayo Clinic Proceedings

Rochester, MN -- A study published in the April Mayo Clinic Proceedings found that extended-release oxybutynin was more effective than immediate-release tolterodine in treating overactive bladder, a condition that is increasing as the population ages.

The symptoms of overactive bladder are urinary urge incontinence, urgency and frequency. More than 17 million people in the United States are affected, making it more prevalent than asthma (15 million), osteoporosis (10 million), diabetes mellitus (7 million) or Alzheimer�s disease (4 million). The cost of treating overactive bladder is considerable for patients, families and third-party payers. In 1995, the estimated cost of urinary incontinence in patients older than 65 years was $26.3 billion.

"Even though overactive bladder is not life threatening, it nonetheless decreases the quality of life for many patients," write Daniel Elliott, M.D., Deborah Lightner, M.D., and Michael Blute, M.D., of Mayo Clinic, in an accompanying editorial. "The medical dollars spent on this problem are increasing. Therefore, it is imperative for physicians to remain current on the latest advances in this field and to prescribe wisely so that their patients receive the most effective and cost-effective medication with the least adverse effects for this troublesome medical condition."

The randomized, double-blind trial was done by the Overactive Bladder Judging Effective Control and Treatment (OBJECT) Study Group comprising 37 physicians. Rodney Appell, M.D. of Baylor College of Medicine, Houston, Texas, is the first author on the Proceedings article.

At 37 study centers across the United States, 378 participants were randomized into two groups to receive treatment with extended-release oxybutyinin or with tolterodine. The study compared the tolerability and efficacy of the two drugs.

At the end of the study, both drugs had improved symptoms of overactive bladder, but extended-release oxybutynin was more effective than tolterodine in each of the main outcome measures: weekly urge incontinence, total incontinence and urination frequency. Both groups had similar rates of dry mouth, the most common adverse effect of treatment with these drugs, and other adverse events.

The study was funded by ALZA Corporation of Mountain View, Calif., the pharmaceutical company that markets oxybutynin. The study�s authors also disclosed their financial ties to the company. The institutional review boards of each participating study center approved the study, and each subject signed an institutional review board-approved consent form.

Mayo Clinic Proceedings is a peer-reviewed and indexed general internal medicine journal, published for 75 years by Mayo Foundation, with a circulation of 130,000 nationally and internationally.