Bronchodilator combinations in animals and in man.

Combined bronchodilator effects of the beta 2-agonist pirbuterol and theophylline were studied in anaesthetized rats and in asthmatic outpatients. In rats, pirbuterol was more effective than aminophylline in reducing methacholine-induced bronchoconstriction without counteracting associated hypotension. In combination they caused additive bronchodilatation. In asthmatic patients, the combination pirbuterol + theophylline + hydroxyzine was as effective as the control combination ephedrine + theophylline + hydroxyzine, both differing significantly from the placebo. Thus, a beta 2-agonist may not be superior to ephedrine in these combinations.