Alcohol ingestion acutely lowers blood pressure (BP) with vasodilation and sympathetic activation in Oriental subjects. We examined the effects of beta blockade on cardiovascular and neurohumoral actions of alcohol in Japanese men with mild-to-moderate
essential hypertension. Ten hypertensive patients (54+/-5 years, mean+/-SE) were given 1 ml/kg of alcohol or isocaloric control drink with a light meal in the evening before and 5-7 days
after treatment with
propranolol (20 mg three times daily). BP and heart rate (HR) were measured every 30 min for 24 h in each period. Blood sampling and echocardiographic examination were carried out before (17.00 h) and after (19.00 h) intake of alcohol or control drink, Before treatment, alcohol ingestion caused significant decreases in BP, total peripheral resistance and serum
potassium concentration, while it increased heart rate (HR), cardiac output (CO), plasma
norepinephrine and plasma
renin activity (PRA). Treatment with
propranolol significantly decreased BP and HR for 24 h.
Propranolol and alcohol showed an additive depressor effect on night-time BP, and the alcohol-
induced hypotension was similar before and after
propranolol treatment. The alcohol-induced changes in HR, CO, PRA and serum
potassium were significantly attenuated by
propranolol. These results suggest that activation of the sympathetic nervous system plays a role in alcohol-induced cardiac stimulation,
renin release and
hypokalemia through beta receptors. Moderate doses of beta-blockers may not modify alcohol-induced BP reduction in Oriental subjects with
hypertension.