Does alcohol intensify the hemodynamic effects of nitroglycerin?

To evaluate the combined effects of alcohol and nitroglycerin on cardiovascular hemodynamics, M‐mode echocardiography and sphygmomanometric blood pressure measurements were performed on two groups of normal subjects, before and after the administration of nitroglycerin, both in the sober state and during alcohol intoxication. In the first part of the study, 0.5 mg of nitroglycerin was given sublingually to 10 healthy volunteers 5–10 minutes after they had ingested 1 g/kg body weight of ethanol within a 30‐minute period. Control experiments substituted juice for ethanol. The combined effects of ethanol and nitroglycerin on left ventricular diameters, systolic blood pressure, and wall stress were not significantly different from those of juice and nitroglycerin; heart rate and diastolic blood pressure were increased more (p < 0.01) by ethanol and nitroglycerin. In the second part of the study, 1.0 mg of nitroglycerin was administered to a second group of 10 healthy volunteers, first in the control state and again 60 minutes after the subjects had ingested 1 g/kg body weight of ethanol within a 60‐minute period. Systolic blood pressure and wall stress were significantly lower (p < 0.01) after ethanol and nitroglycerin than after nitroglycerin before ethanol intake. We conclude that the nitroglycerin‐induced reductions in left ventricular preload and afterload are not increased by alcohol during the very early phase of intoxication. However, 1 hour or more after alcohol ingestion nitroglycerin may decrease left ventricular afterload to a level significantly lower than that seen after nitroglycerin in the sober state. These data suggest first, that alcohol does not deprive nitroglycerin of its beneficial hemodynamic effects, and second, that the susceptibility to nitroglycerin‐induced hypotension may be increased during the late phase of intoxication.