Up to 40% of postmenopausal women have overactive bladder — an urgent and frequent need to urinate, sometimes resulting in incontinence. The most common drug treatment is oxybutynin (Ditropan), which is an anticholinergic medication. That means it blocks the neurotransmitter acetylcholine, relaxing the bladder and decreasing the need to urinate. But anticholinergics can cause dry mouth and constipation, side effects that prompt many women with overactive bladder to stop taking the medication. Now, a study in Menopause: The Journal of the North American Menopause Society (September 2011) finds there's an equally effective alternative that lacks those side effects — an ultra-low-dose estradiol vaginal ring (Estring). Vaginal estrogen cream can help manage overactive bladder symptoms, but creams can be messy and must be reapplied several times a week. The ring is worn continuously and can stay in place for three months.
The study. The study included 59 postmenopausal women with overactive bladder, defined as urinating 10 or more times in 24 hours. Thirty-one were randomly assigned to take oxybutynin; 28 received the vaginal ring. The women recorded their urination times during two 72-hour periods, once at the start of the 12-week study and again at the end. They also filled out questionnaires on the distress caused by their symptoms and their overall quality of life.
The results. Both groups benefited. On average, the women taking oxybutynin had three fewer urinations per day, and those who used the vaginal ring urinated 4.5 fewer times per day. Scores on the questionnaires also improved for both groups. But the women taking oxybutynin reported far more side effects, including dry mouth (85%), constipation (52%), and blurry vision (44%), which prompted four to discontinue treatment. The most common side effect among vaginal ring users was vaginal discharge (41%). Four of the vaginal ring users discontinued treatment because they had difficulty keeping the ring in place.
Limitations and implications. The main limitation of this experiment is that results might have been skewed because a placebo wasn't used to "blind" participants to the treatment they were receiving, in part because the researchers were concerned that placebo rings might cause discomfort or other effects. But in this case, lack of blinding may not be that problematic, because all participants received some form of intervention. One downside of the vaginal ring is its cost: $227 for three months of treatment, compared with $74 for oxybutynin. But as an editorial accompanying the study notes, more than half of women who are prescribed oxybutynin never refill their prescriptions. If the vaginal ring leads to better compliance and thus the use of fewer incontinence pads, the ring's higher initial cost may pay off in the long run. Also, prescription drug coverage may substantially reduce the cost of the ring.