Anticholinergic drugs versus placebo for overactive bladder syndrome in adults

Around 16% of adults have symptoms of overactive bladder (urgency with frequency and/or urge incontinence). The prevalence increases with age. Anticholinergic drugs are commonly used to treat this condition.

To determine the effects of anticholinergic drugs for the treatment of overactive bladder syndrome.

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 14 June 2005) and the reference lists of relevant articles.

Randomised or quasi-randomised trials in adults with overactive bladder syndrome that compared an anticholinergic drug with placebo treatment or no treatment.

Two reviewer authors independently assessed eligibility, trial quality and extracted data. Data were processed as described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005).

Sixty -one trials, 42 with parallel-group designs and 19 crossover trials were included (11,956 adults). Most trials were described as double-blind but were variable in other aspects of quality. The crossover trials did not present data in a way that allowed inclusion in the meta-analysis. Nine medications were tested: darifenacin; emepronium bromide or carrageenate; oxybutynin; propiverine; propantheline; tolterodine; trospium chloride; and solifenacin. One trial included the newer, slow release formulation of tolterodine. At the end of the treatment period, cure or improvement (relative risk (RR) 1.39, 95% CI 1.28 to 1.51), difference in leakage episodes in 24 hours (weighted mean difference (WMD) -0.54; 95% CI -0.67 to -0.41) and difference in number of voids in 24 hours (WMD -0.69; 95% CI -0.84 to -0.54) were statistically significant favouring medication. Statistically significant but modest sized improvements in quality of life scores were reported in recently completed trials. There was three times the rate of dry mouth in the medication group (RR 3.00 95% CI 2.70 to 3.34) but no statistically significant difference in withdrawal (RR 1.11, 95% CI 0.91 to 1.36). Sensitivity analysis, while limited by small numbers of trials, showed little likelihood that the effects were modified by age, sex, diagnosis, or choice of drug.

The use of anticholinergic drugs by people with overactive bladder syndrome results in statistically significant improvements in symptoms. Recent trials suggest that this is associated with modest improvement in quality of life. Dry mouth is a common side effect of therapy but did not seem to have an effect on the numbers of withdrawals. It is not clear whether any benefits are sustained during long-term treatment or after treatment stops.