Erectile dysfunction (ED) is common among men taking antihypertensive drugs to control blood pressure. We evaluated the safety and efficacy of sildenafil citrate for treating ED in men taking multiple antihypertensive medications in a randomized, double-blind, placebo-controlled trial.A total of 568 men (> or =18 years) with ED and hypertension who were taking two or more antihypertensives were randomized to sildenafil (n = 281) or matching placebo (n = 287) for a 6-week double-blind trial followed by a 6-week open-label phase during which all patients received sildenafil. Primary efficacy variables were questions (Q) 3 and 4 (frequency of erections and penetration) of the International Index of Erectile Function (IIEF), and secondary efficacy variables were two global efficacy assessment (GEA) questions regarding improvement in erections and intercourse.A total of 562 men (mean age, 59 years) took > or =1 dose of study drug. At week 6, mean scores on both Q3 and Q4 improved significantly among sildenafil-treated compared with placebo-treated patients. In regard to Q3 and Q4 there were no differences between patients taking two and those taking three or more antihypertensive agents. In all, 71% and 69% of sildenafil-treated patients reported improved erections (GEA1) and intercourse (GEA2) compared with 18% and 20% of placebo-treated patients, respectively. By week 12, >80% of all patients (regardless of initial treatment group) had improved erections and intercourse. During double-blind treatment, 40% of sildenafil-treated and 25% of placebo-treated patients experienced adverse events; fewer than 2% in each group discontinued because of adverse events.Sildenafil was an effective and well tolerated treatment for ED in men receiving multiple antihypertensives. The results suggest that there were no additional safety risks associated with the use of sildenafil in these patients.