Comparison of the cardiopulmonary effects of subcutaneously administered epinephrine and terbutaline in patients with reversible airway obstruction

Abstract

The cardiopulmonary effects of epinephrine and terbutaline were compared in a doubleblind crossover study in 23 subjects with chronic obstructive airway disease. On each of three days each subject received a single subcutaneous dose of saline, 0.25 mg of epinephrine or 0.5 mg of terbutaline. Treatment with epinephrine produced significant increases in forced vital capacity (FVC), forced expiratory volume in one second (FEV-1), maximal expiratory flow rate (MEFR) and maximal mid-expiratory flow (MMEF). Terbutaline caused even more pronounced increases in all four parameters and exhibited a longer duration of action. Neither drug altered arterial pH, arterial oxygen pressure (PaO-2), or arterial carbon dioxide pressure (PaCO-2). With regard to cardiovascular effects, no alterations in either systolic or diastolic pressure were observed. Administration of epinephrine and terbutaline caused statistically significant increases in heart rate. The effect of terbutaline was more pronounced that that of epinephrine. In addition, terbutaline caused a heart rate-related depression of the T-wave of the lead 2 ECG. Neither drug altered any of the hematologic, hemochemical or urinary parameters monitored before and after treatment. Side effects were seen in eight subjects after administration of saline solution, in 13 subjects after epinephrine and in 19 subjects after terbutaline. None of these side effects was considered clinically serious and none required treatment. It is concluded from this study that subcutaneously administered terbutaline is a more effective bronchodilator than epinephrine.