Fifty RCTs and three pooled analyses were included in the review. Most included trials had a Jadad score of 3 or more.
Different doses and formulations of the same drug:
Efficacy: There were no significant differences between tolterodine immediate release 1mg and tolterodine immediate release 2mg for micturitions per 24 hours, volume voided per micturition and urge urinary incontinence episodes per 24 hours. With regard to adverse events, only dry mouth was significantly more frequent in those patients taking tolterodine immediate release 2mg (OR 0.52, 95% CI 1.037 to 0.72, p<0.0001).
Immediate release compared to extended release formulations: Oxybutynin and tolterodine were evaluated in immediate release and extended release formulations. Patients randomised to oxybutynin immediate release were significantly more likely to experience the occurrence of any adverse event (OR 1.90, 95% CI 1.03 to 3.51, p=0.04; three trials), dry mouth (OR 1.45, 95% CI 1.02 to 2.05, p=0.04; five trials). Withdrawals due to adverse events, headache, constipation and vision abnormality were similar for both formulations. Patients randomised to tolterodine extended release formulation experienced a lower number of micturitions per 24 hours (WMD 0.34, 95% CI 0.02 to 0.66, p=0.03; two trials) and a higher volume voided per micturition (WMD -9.12, 95% CI -14.13 to -4.12, p=0.0004; two trials), but a similar number of incontinence episodes and pad use per day as patients randomised to tolterodine immediate release formulation. Tolterodine extended release formulations had a significantly lower rate of dry mouth (OR 1.39, 95% CI 1.13 to 1.71, p=0.002; two trials), but a higher rate of headache (OR 0.53, 95% CI 0.34 to 0.81, p=0.004; two trials). Withdrawals due to adverse events and constipation were similar in both groups. Two trials compared propiverine hydrochloride immediate release and extended release formulations and showed similar rates of adverse events, dry mouth, constipation, headache and vision abnormality.
Comparisons of different drugs:
There was no difference in efficacy between oxybutynin 5mg and tolterodine 2mg. Adverse events were significantly more common in patients randomised to oxybutynin. Compared to most other study drugs oxybutynin was similarly effective, but tended to show higher rates of adverse effects.
One study showed that tolterodine was less efficacious compared to solifenacin; compared to most other study drugs, tolterodine was similarly effective and showed similar rates of adverse effects.
Different routes of administration:
Two trials reported outcomes for different routes of administration. Patients randomised to oral treatment were more likely to experience dry mouth and constipation. Patients randomised to transdermal administration were more likely to experience localised application side effects and withdrawal due to adverse events.
There was no evidence of publication bias (data not reported).