Antimuscarinics only moderately effective for overactive bladder

Sep 17 2012

By medwireNews Reporters

A comprehensive review of oral antimuscarinics for the treatment of overactive bladder concludes that the efficacy of treatment is, at best, moderate.

"On review, the results are scattered, and no treatment stands out in all assessed outcomes," write Lucas Bachmann (Medignition Research Consultants, Zug, Switzerland) and colleagues in European Urology.

The meta-analysis, which included nearly 40,000 patients treated with various drugs, formulations, and dosages, suggests that the currently prescribed antimuscarinics are an equivalent first choice to start treatment of overactive bladder.

The exceptions, however, are high doses of oxybutynin and propiverine as these agents have more unfavorable adverse event profiles.

The review included 76 studies enrolling 38,662 patients to test the efficacy of antimuscarinics, and 90 trials enrolling 39,919 to assess adverse events.

Efficacy was assessed based on six outcomes, including perception of cure or improvement, urgency episodes per 24 hours, leakage episodes per 24 hours, urgency incontinence per 24 hours, micturitions per 24 hours, and nocturia episodes per 24 hours. Adverse outcomes included gastrointestinal, visual, urinary-tract-related, neurologic, cardiac, respiratory tract-related, and dermatologic events.

In the subset of studies reporting treatments and dosages used in clinical practice, 40 mg/day trospium chloride, 100 mg/g per day oxybutynin topical gel, and 4 mg/day fesoterodine had the best efficacy.

"For the treatment of leakage or nocturia episodes, none of the examined agents showed satisfactory effects," according to Bachmann and colleagues.

In terms of adverse events, various drugs, formulations, and dosages were similar to placebo, including 5 mg/day oxybutynin extended-release (ER), 15 mg/day propiverine immediate-release (IR), 5 mg/day oxybutynin IR, oxybutynin topical gel, and 1.3 mg/day oxybutynin.

In an analysis of 21 treatments used frequently in clinical practice, 100 mg/g per day oxybutynin topical gel, 5 mg/day solifenacin, 4 mg/day tolterodine ER, 15 mg/day oxybutynin ER, and 0.2 mg/day imidafenacin had the best overall adverse-event profile.

By contrast, 20 mg/day oxybutynin IR, followed by 15 mg/day oxybutynin IR, 45 mg/day propiverine IR, 10 mg/day oxybutynin IR, and 15 mg/day darifenacin had the worst event profile.

The researchers note that while antimuscarinics are generally well accepted, nonadherence is a problem, with up to 40% of patients discontinuing treatment because of adverse events.

"Given the clear disadvantages of higher dosages of oxybutynin and propiverine, these treatments should not be used or should be replaced, if possible," they conclude.

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