Interactions of chlorpheniramine ethanol combinations: acute toxicity and antihistaminic activity

Significant toxicologic and pharmacologic interactions occurred between chlorpheniramine maleate and 25% $\text{v}\text{v}$ ethanol at several dosage combinations. Conditions of both independence and antagonism of acute toxicity were observed in LD50 determinations of chlorpheniramine-ethanol combinations in mice, and confirmed expected results based on the toxicologic pattern of the agents when administered singly. Enhancement of the antihistaminic action of chlorpheniramine by ethanol was demonstrated during histamine-aerosol challenge studies in guinea pigs.