Endothelial antioxidant administration ameliorates the erectile response to PDE5 inhibitors regardless of the extension of the atherosclerotic process

INTRODUCTION: The lack of phosphodiesterase type 5 inhibitor effects in patients with erectile dysfunction (ED) of arterial origin may be caused by an endothelial dysfunction that causes a series of biochemical alterations leading to a reduced nitric oxide (NO) bioavailability and increased oxidative stress.AIM: The aim of this study was to evaluate the effects of the treatment with endothelial antioxidant compounds (EAC) on the erectile response to sildenafil in patients with arterial ED already treated with sildenafil (100 mg twice a week for 8 weeks).MEAN OUTCOME MEASURES: A patient was considered responsive when the 5-item International Index of Erectile Function questionnaire score increased by >5 points.METHODS: Fifty-three patients with arterial ED, hypertension, and diabetes mellitus were randomly given, for 8 weeks, EAC (1 dose/day) and, after a wash out of 8 weeks, sildenafil (100 mg) plus EAC. The patients were divided into the following four groups: A (N = 12): patients with ED alone; B (N = 14): patients with ED plus atheromasic plaques and/or increased intima-media thickness of common carotid arteries; C (N = 14): patients with ED plus lower limb artery abnormalities; and D (N = 13): patients with ED plus carotid and lower limb artery abnormalities.RESULTS: The administration of EAC plus sildenafil resulted in a significantly higher number of responsive patients (N = 36, 68%) compared with sildenafil alone (N = 24, 45%) or EAC alone (N = 17, 32%). The percentage of patients who successfully responded to the combined treatment increased in the various groups. It was 83%, 64%, 71%, and 54%, respectively, for groups A, B, C, and D. Furthermore, patients treated with EAC and sildenafil reached a successful response in a shorter length of time (3 weeks) compared with patients responsive to sildenafil (5.2 weeks) or EAC (5.7 weeks) alone.CONCLUSION: EAC administration to patients with arterial ED improved the success rate to sildenafil. These data suggest that, in such patients, a combined treatment may be considered to increase bioavailable NO and to neutralize radical oxygen species, which in turn inactive NO.