Airways responses to oral ethanol in normal subjects and in patients with asthma

Abstract

The effect of oral ethanol on airflow was studied in 5 normal subjects and 5 patients with asthma. On 4 different study days, each subject was asked to drink 40 ml of either water or 20%, 40% or 60% ethanol, and measurements were made of specific airways conductance (sGaw), blood ethanol levels, pulse rate and blood pressure. In some subjects in both groups there was a significant immediate fall in sGaw after drinking ethanol (below 5% confidence limits). Once absorbed, ethanol had a slight bronchodilator effect in 2 normal subjects and in 3 patients with asthma (5% level). Sixty per cent ethanol, when drunk slowly, showed significant bronchodilatation in 4 out of 5 patients with asthma and in one normal subject (5% level) with no acute fall in sGaw. Pulse rate and blood pressure did not change after water, 20% and 40% ethanol in either group, but immediately after 60% ethanol normal subjects showed a significant rise in pulse rate (P less than 0.01) which was not seen in patients with asthma. The immediate changes in sGaw and pulse rate may be due to stimulation of irritant receptors in the upper airways. Ethanol may act directly on bronchial smooth muscle to produce bronchodilatation and may be useful as a bronchodilator when given intravenously.