Effects of Sildenafil on Cardiopulmonary Responses During Stress

Abstract

To investigate possible effects of sildenafil on the cardiopulmonary responses during sexual intercourse we evaluated cardiopulmonary responses during exercise in a group of impotent patients. The study sample included patients with erectile dysfunction who underwent a cardiopulmonary exercise test before and after the administration of 100 mg. sildenafil citrate. Cardiopulmonary exercise test parameters at rest, at the anaerobic threshold, at peak exercise and at 1-minute recovery were recorded, including systolic and diastolic blood pressure, the heart rate, O2 consumption, CO2 production, ventilation and the respiratory rate. Furthermore, O2 consumption per kg. body weight, the ventilatory equivalent for O2 consumption (ventilation/O2 consumption) and CO2 production (ventilation/CO2 production), the respiratory quotient, metabolic equivalents metabolic equivalents, oxygen pulse (O2 consumption/heart rate) and the change in O2 consumption/change in heart rate were calculated. In 2 of the 43 patients enrolled in the study myocardial ischemia and high blood pressure were detected at rest in 2, respectively, who were excluded from analysis. In the remaining 41 patients with a mean age +/- SD of 52.3 +/- 8.6 years a statistically significant decrease in systolic and diastolic blood pressure was noted after sildenafil use at all stages tested (p <0.002 to 0.001). The heart rate mildly increased after sildenafil use at rest and at peak exercise (p = 0.018). The O2 pulse decreased at the anaerobic threshold (p = 0.003), peak exercise (p = 0.001) and recovery (p = 0.047). In the 11 patients with a mean age of 40.8 +/- 10.12 years who had psychogenic erectile dysfunction the only 2 parameters affected were an increased heart rate and decreased systolic blood pressure at rest, while O2 consumption/heart rate decreased at the anaerobic threshold. In the 18 patients with a mean age of 61.1 +/- 8.9 years who had organic erectile dysfunction and an unremarkable medical history a decrease was noted in systolic and diastolic blood pressure at rest and at peak exercise, and diastolic blood pressure also at recovery, while the heart rate increased at recovery. In the 12 patients with a mean age of 60.16 +/- 9.12 years who had treated cardiovascular disease systolic and diastolic blood pressure decreased at all states and O2 consumption/heart rate at the anaerobic threshold and at peak exercise, while increased values were noted for the respiratory rate at the anaerobic threshold and ventilation/CO2 production at recovery. Hemodynamic changes after sildenafil administration should be considered minimal in concert with patient health status. Younger patients without signs of systemic atherosclerosis compensate the vasodilatory effect of sildenafil during exercise, while in older patients with vasculogenic erectile dysfunction moderate changes may be noted regardless of cardiovascular disease in the medical history.