Cardiac, pulmonary and neuromuscular effects of clenbuterol and terbutaline compared with placebo.

1 Cardiac, neuromuscular (tremor) and pulmonary effects of multiple single oral doses of clenbuterol (40, 60 and 80 micrograms) and terbutaline (2.5 and 5 mg) were compared with placebo in thirteen patients with reversible obstructive airways disease. 2 The percent change in the bronchodilator and neuromuscular effects of clenbuterol and terbutaline were greater than that of the cardiac activity. 3 Both drugs decreased T wave amplitude and occasionally caused J point ST segment depression. These changes were considered typical of this class of drugs and clinically insignificant. 4 While these drugs had comparable cardiac, pulmonary and neuromuscular effects, clenbuterol, at larger doses, had a higher incidence of transient headaches and nervousness.