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.

The Cochrane Incontinence Group trials register was searched to January 2002.

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

Two reviewers independently assessed eligibility, trial quality and extracted data. Data were processed as described in the Cochrane Collaboration Handbook.

Fifty one trials, 32 parallel designs and 19 crossover designs were included (6713 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. Seven medications were tested: darifenacin; emepronium bromide or carrageenate; oxybutynin chloride; propiverine; propantheline; tolterodine; and trospium chloride. One trial included the newer, slow release, formulation of tolterodine. After treatment, cure/improvement (RR 1.41, 95%CI 1.29 to 1.54), changes in leakage episodes in 24 hours (WMD -0.56, 95%CI -0.73 to -0.39), number of voids in 24 hours (WMD -0.59, 95%CI -0.83 to -0.36), maximum cystometric volume (WMD 53.85 ml, 95%CI 42.28 to 65.41), and volume at first contraction (WMD 52.25 ml, 95%CI 37.45 to 67.06), were significantly in favour of medication. Medication was associated with significantly higher residual volumes (WMD 4.06 ml, 95%CI 0.73 to 7.39) and more than two and a half times the rate of dry mouth (RR 2.61, 95% CI 2.27 to 3.00). Sensitivity analysis, while limited by small numbers of trials, showed little likelihood that these 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 improvement in symptoms. However, the clinical significance of these differences is uncertain, and the longer-term effects are not known. Dry mouth is a common side effect of therapy.