Cardiovascular effects of sildenafil citrate (Viagra (R)): A naturalistic cross-over study

In a cross-over study we investigated the effects of sildenafil (single dos es of 25- or 50mg) on cardiovascular autonomic nervous system (ANS) functio n assessed by serial recordings of blood pressure, conventional 12-lead ele ctrocardiograms and standardized, time-and frequency domain indices of hear t rate variability (HRV) in 21 men with erectile dysfunction. More than hal f of these patients had multiple comorbidities. Sildenafil induced signific ant mean reductions from baseline in resting blood pressure, accompanied by a reflex increase in heart rate. There were no significant changes after a dministration of sildenafil in any other of the ANS function indices. These preliminary findings suggest that sildenafil does not significantly affect cardiac ANS function in patients with erectile dysfunction.