Histamine receptor antagonism of intolerance to alcohol in the Oriental population.

The Oriental flushing reaction is an adverse response to alcohol that appears to be genetically determined. In this study, the Oriental flushing reaction that was produced with ingestion of small amounts of alcohol was antagonized by antihistamine administration. A group of 17 subjects was tested. Each subject received placebo, diphenhydramine 50 mg (H-1 receptor antagonist), and cimetidine 300 mg (H-2 receptor antagonist) singularly and in combination. Alcohol was then administered orally. Most subjects given placebo experienced the typical flushing reaction that included a cutaneous flush, increase in skin temperature, decrease in blood pressure, increase in pulse rate and subjective symptoms such as dizziness, sleepiness, anxiety, headache, generalized weakness, and nausea. The flush, temperature and systolic hypotension were significantly blocked by the combined antihistamine administration. Cimetidine given alone blocked the flush, temperature increase, and systolic hypotension significantly more than diphenhydramine but less than the combined antihistamines. Diphenhydramine was similar to placebo in its effect on the flushing reaction. The role of histamine in the expression of tolerance to alcohol is not known. Antihistamine antagonism of the adverse flushing reaction suggests that histamine receptors may participate in the intolerance to ethanol in Orientals. Histamine may be an important protective factor in the low prevalence of alcoholism in Orientals.