THE EFFECT OF ANTIHISTAMINE SUBSTANCES AND OTHER DRUGS ON HISTAMINE BRONCHOCONSTRICTION IN ASTHMATIC SUBJECTS 1

Abstract

Previous studies have demonstrated that quantitative amts. of bronchoconstriction may be produced in certain asthmatic subjects by parenteral histamine. In the present communication, attention was given to the ability of certain antihistamine substances and other drugs to protect against this bronchoconstriction. The degree of bronchoconstriction after given doses of histamine was measured by recording the decrease in the vital. capacity. Benadryl administered intravenously produced a remarkable, rapid protection against both the systemic and bronchoconstrictive effects of parenteral histamine. Pyribenzamine hydrochloride given orally in 50 mgm. doses produced a slow and more irregular protection. Atropine sulfate furnished complete protection against the bronchoconstrictive effects of nebulized histamine in one instance, but only partial protection against intravenously administered histamine. Theophylline with ethylenediamine given by the intravenous route afforded prompt and potent protection against the tracheobronchial effects of intravenous histamine. Intramuscular epinephrine gave prompt and complete protection against the bronchoconstrictive effects of histamine, while intramusc. ephedrine sulfate also produced complete protection. With ephedrine, however, the protection was slow in onset, and only became complete 2 hrs. after the drug was administered. It appears that this method of study provides a means of measuring the bronchodilator activity of the various sympathomimetic amines.