A systematic review 6 including 50 studies with a total of 12 580 subjects was abstracted in DARE. Sildenafil (35 trials, n=7 135) significantly improved erections compared with placebo: 76% versus 23%. The NNT was 1.9 (95% CI 1.8 to 2.0). It also reduced all-cause withdrawals and lack of efficacy withdrawals compared with placebo, but increased withdrawals due to adverse events (NNH 120, 95% CI 67 to 560). The NNH for reporting at least one adverse event was 4.9 (95% CI 4.2 to 6.0). Headache was the most commonly reported adverse effect (17%), followed by flushing (13%) and dyspepsia (7.8%).
Tadalafil (8 trials, n=2 071) significantly improved erections compared with placebo: 75% versus 24%. The NNT was 1.9 (95% CI 1.8 to 2.1). It also reduced all-cause withdrawals and lack of efficacy withdrawals compared with placebo, but increased withdrawals due to adverse events (NNH 52, 95% CI 29 to 260). The NNH for reporting at least one adverse event was 4.6 (95% CI 3.4 to 7.2). Headache was the most commonly reported adverse effect (13%), followed by dyspepsia (10%) and flushing (4.8%).
Vardenafil (7 trials, n=3 374) significantly improved erections compared with placebo: 71% versus 22%. The NNT was 2.0 (95% CI 1.9 to 2.2). It also reduced all-cause withdrawals and lack of efficacy withdrawals compared with placebo, but increased withdrawals due to adverse events (NNH 65, 95% CI 37 to 250). Headache was the most common adverse effect (15%), followed by flushing (13%) and rhinitis (7.9%).
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