OAB agents' efficacy declines in multiple drug users

May 15, 2010

A post hoc analysis of two phase III antimuscarinic trials shows that multiple medication use is a major factor in failure of antimuscarinics.

St. Petersburg, FL-Which overactive bladder patients are least likely to do well with antimuscarinic drug therapy? The answer will surprise you.

First author David Staskin, MD, associate professor of urology at Tufts University School of Medicine, Boston, presented the analysis here at the Society for Urodynamics and Female Urology winter meeting. He and his team looked at intake forms from the 1,165 patients with OAB to determine which ones were unhappy with their prior medications.

Multiple medication use (more than seven medications per day) and more severe OAB (more than three urge incontinence episodes per day) were significant predictors of perceived lack of efficacy in a univariate logistic regression analysis. But only multiple medication use remained significant in the multivariate analysis, which also pegged ideal body weight as a significant predictor, whereas mean number of urge incontinence episodes per day was only of borderline significance.

"The biggest takeaway is that patients with OAB are on multiple medications and that this very strongly correlates with patient-reported lack of efficacy," Dr. Staskin told Urology Times.

Patients took a wide range of other medications, such as those for diabetes and hypertension, but not other OAB drugs, Dr. Staskin explained.

Why multiple medication use is such a strong predictor isn't clear, but "possible explanations include drug-drug interactions, more severe baseline disease, and even wrong diagnosis," he said.

Dr. Staskin serves as a consultant/adviser to Allergan.