To compare efficacy and tolerability between 100-mg and 50-mg sildenafil doses in five double-blind, placebo-controlled (DBPC) fixed-dose studies.


Doses were compared for the change (baseline to end of 8–12 weeks of DBPC treatment) in score on the Erectile Function (EF) domain of the International Index of Erectile Function (IIEF; from five fixed-dose studies, > 1500 men); the per-patient estimated percentage of occasions that a specified Erection Hardness Score (EHS; from two of the five fixed-dose studies, > 500 men) was achieved, computed from logistic regression; the odds ratio (OR) of achieving EHS3 (hard enough for penetration, but not completely hard) and EHS4 (fully hard and completely rigid); and the adverse event incidence by treatment (from all five fixed-dose studies).


For the 100-mg vs. 50-mg dose, IIEF-EF score improvement was consistently greater across the five studies and was statistically significant when data from two studies with similar design were pooled (10.7 ± 0.64 vs. 8.9 ± 0.83, p = 0.0287); and during the first 2 weeks of treatment, the odds of achieving EHS4 erections were almost doubled in one study (OR = 1.77, p = 0.0398). Sildenafil was generally well tolerated at either dose.


Men with erectile dysfunction treated with 100-mg compared with 50-mg sildenafil may be more likely to achieve a greater improvement in erectile function and, within the first 2 weeks, completely hard and fully rigid erections, with little or no greater risk to tolerability.