ObjectivesTo assess the acute effect of sildenafil citrate on blood pressure and heart rate in men with erectile dysfunction taking concomitant antihypertensive medication.DesignPost-hoc subanalysis of five, 12- or 24-week, prospective, randomized, double-blind, placebo-controlled studies.SettingPrivate-practice and academic urology clinics.PatientsA total of 1685 men with erectile dysfunction of ≥ 6 months duration, of whom 667 (sildenafiln= 406, placebon= 261) were taking antihypertensive medication (diuretic, β-blocker, α-blocker, angiotensin converting enzyme inhibitor, and/or calcium antagonist). Of the patients taking antihypertensive medication, 608 (91%) completed the studies (374 of 406 receiving sildenafil, 234 of 261 receiving placebo).InterventionsThe last dose of oral sildenafil (25–200 mg) or placebo was taken at home on the morning of the final clinic visit. Patients taking antihypertensive medication maintained usual dosing schedules.Main outcome measurementsSitting systolic (SBP)/ diastolic blood pressure (DBP) and heart rate at baseline and after dosing with sildenafil or placebo (end-of-treatment visit).ResultsMean changes from baseline in SBP/DBP for men taking antihypertensive medication were −3.6/−1.9 mmHg for those receiving sildenafil and −0.8/−0.1 mmHg for those receiving placebo compared with −2.2/−2.0 mmHg and −0.1/0.4 mmHg, respectively, for men not taking antihypertensive medication. Mean changes from baseline in heart rate for men taking antihypertensive medication were −0.6 beats/min after sildenafil and −0.9 beats/min after placebo compared with 0.4 beats/min and −0.6 beats/min, respectively, for patients not taking antihypertensive medication. Differences in SBP, DBP, and heart rate between the patients taking and those not taking antihypertensive medication were small.ConclusionsThe acute, short-term effects of oral sildenafil on blood pressure and heart rate in men with erectile dysfunction were small and not likely to be clinically significant in those taking concomitant antihypertensive medication.