Sildenafil Citrate ( Viagra) effect on the pattern of controlled hypotension induced by sodium nitroprusside or nitroglycerin

Abstract

Oral sildenafil Citrate (viagra) is an effective treatment for erectile dysfunction (ED) . There are reports of serious hypotension when sildenafil citrate is given to patients taking certain vasodilators . This study was designed to assess the effects of sildenafil citrate (viagra) therapy on the dose, efficacy and safty of I.V. infusion of nitrovasodilators; sodium nitroprusside or nitroglycerin, to induce controlled "delibrate" -    !g/kg/min) or nitroglycerin  "#!$!%& &'  ' (  (  (&& (& &% &)*!$ & &&( variables; mean arterial blood pressure "MAP" and "ECG" pattern, were monitored. In control groups it was found that, ( SNP) infusion achieved a rapid induction of controlled hypotension accompanied by reflex hypertension after drug infusion discontinuation. However, (NTG) infusion failed to decrease the (MAP) to the target level, and upon discontinuation of its infusion, return of arterial blood pressure to control values, was moderately slower. Comparison between the effect of the two drugs revealed a significant difference in mean arterial blood pressure after infusion. Treatment with sildenafil citrate (viagra) , augmented the (MAP) reduction caused by (SNP), and improved the lack of potency of (NTG) induced hypotension . Comparison between the effect of the two drugs revealed a significant difference during drug infusion, and after drug infusion discontinuation. Doses of (SNP) or (NTG) required to induce delibrate hypotension in groups treated with sildenafil were decreased when compared to that in control groups. Sodium nitroprusside (SNP) infusion induced increase in the mean heart rate (HR) without ECG changes in control or treated groups. Sildenafil citrate treatment increased significantly the initial HR in comparison to control group. In contrast, nitroglycerin (NTG) infusion, did not change significantly the (HR) in control group. However, in sildenafil citrate treated group, (NTG) infusion induced significant increase in the HR throughout the study , and there was also changes in PR QRS, and QT interval in one case.