Twelve RCTs (n=2,816) were included in the review. Sample sizes ranged from 35 to 1,983 participants. Nine of the included studies were considered to be high quality and three were considered to be low quality.
After four weeks of treatment, there was a significant positive effect in favour of tamsulosin compared with terazosin for International Prostate Symptom Score (WMD -1.24, 95% CI -1.98 to -0.51; eight RCTs, n=813 participants). There was no significant statistical heterogeneity between the trials.
There were no significant differences between groups for the outcomes: quality of life (four trials, n=311); maximum urinary flow rate (10 trials, n=972) with significant heterogeneity between trials; average urinary flow rate (seven trials, n=667); residual volume (five trials, n=419) with significant heterogeneity between trials; and prostate volume (four trials, n=362).
Significantly more participants in the terazosin treatment group experienced dizziness (RR 0.38, 95% CI 0.30 to 0.48; eight RCTs, n=2,767 participants), severe hypotension (RR 0.16, 95% CI 0.04 to 0.68; three RCTs, n=332 participants) and dry mouth (RR 0.14, 95% CI 0.03 to 0.77; three RCTs, n=218 participants) than in the tamsulosin treatment group. There was no significant statistical heterogeneity between trials for any of these adverse events. No other adverse events were assessed.
Subgroup analyses were not reported.