Intravenous NAB 365 (clenbuterol) and terbutaline in exercise-induced bronchospasm (EIB).

In a single-blind, placebo-controlled, cross-over study, the effects of intravenous 20 micrograms NAB 365 (clenbuterol) and intravenous 250 microgram terbutaline were compared in nine asthmatic patients with bronchospasm induced by exercise. The exercise consisted of treadmill running. The two beta-adrenergic bronchodilator drugs effectively prevented post-exercise bronchospasm in eight of the nine patients. The effects were superior to those in the untreated group and in the placebo-treated group. Six of the patients treated with terbutaline complained of adverse reactions (tremor, palpitation, tachycardia). No adverse reactions were observed after clenbuterol.