Which anticholinergic drug for overactive bladder symptoms in adults.

BACKGROUND: Around 16% to 45% of adults have overactive bladder symptoms (urgency with frequency and/or urge incontinence - 'overactive bladder syndrome'). Anticholinergic drugs are common treatments.

OBJECTIVES: To compare the effects of different anticholinergic drugs for overactive bladder symptoms.

SEARCH STRATEGY: We searched the Cochrane Incontinence Group specialised trials register (searched 17 January 2002) and reference lists of relevant articles. A search for full publications of abstracts identified in January 2002 was completed in July 2003.

SELECTION CRITERIA: Randomised trials in adults with overactive bladder symptoms or detrusor overactivity that compared one anticholinergic drug with another, or two doses of the same drug.

DATA COLLECTION AND ANALYSIS: Two authors independently assessed eligibility, trial quality and extracted data. Data were processed as described in the Cochrane Reviewers' Handbook.

MAIN RESULTS: Forty nine trials, 39 parallel and 10 cross-over designs were included (11,332 adults). Most trials were described as double-blind, but were variable in other aspects of quality. Crossover studies did not present data in a way that could be included in the meta-analysis.Four trials collected quality of life data (the primary outcome measure) using validated measures; none reported useable data. Oxybutynin versus tolterodine: There were no statistically significant differences for patient perceive improvement, leakage episodes or voids in 24 hours, but fewer withdrawals due to adverse events (RR 0.57, 95% CI 0.43 to 0.75), and less risk of dry mouth (RR 0.60, 95% CI 0.54 to 0.66), with tolterodine. Different doses tolterodine: The usual recommended starting dose (2 mg twice daily) was compared with two lower (0.5 mg and 1 mg twice daily), and one higher dose (4 mg twice daily). The effect of 1 mg, 2 mg and 4 mg doses was similar for leakage episodes and micturitions in 24 hours, with greater risk of dry mouth with 2 and 4 mg doses.Extended versus immediate release preparations of oxybutynin and/or tolterodine: There were no statistically significant differences for cure/improvement, leakage episodes or micturitions in 24 hours, or withdrawals due to adverse events, but there were few data. Overall, extended release preparations had less risk of dry mouth. One extended release preparation versus another: There was less risk of dry mouth with oral extended release tolterodine than oxybutynin (RR 0.75, 95% CI 0.59 to 0.95), but no difference between transdermal oxybutynin and oral extended release tolterodine although some people withdrew due to skin reaction at the trandermal patch site.

AUTHORS' CONCLUSIONS: Where the prescribing choice is between oral immediate release oxybutynin or tolterodine, tolterodine might be preferred for reduced risk of dry mouth. With tolterodine, 2 mg twice daily is the usual starting dose, but a 1 mg twice daily dose might be equally effective with less risk of dry mouth. If extended release preparations of oxybutynin or tolterodine are available, these might be preferred to immediate release preparations because there is less risk of dry mouth. There is little or no evidence available about quality of life, costs, or long-term outcome in these studies. There were insufficient data from trials of other anticholinergic drugs to draw any conclusions.