Drug Interaction Report

MONITOR: Concomitant use of beta-2 adrenergic agonists with tricyclic antidepressants (TCAs) may increase the risk and/or severity of cardiovascular adverse effects such as hypertension, palpitation, chest pain, and arrhythmia. In addition, both classes of drugs have been reported to produce electrocardiographic changes including flattening of the T wave and prolongation of the QTc interval, and these effects may be additive during coadministration.

MANAGEMENT: Caution is advised if beta-2 agonists are used with TCAs, or within two weeks of discontinuing the latter. Cardiovascular status should be closely monitored.

Although they are often combined in clinical practice, the concomitant use of beta-2 adrenergic agonists and corticosteroids may result in additive hypokalemic effects. Since beta-2 agonists can sometimes cause QT interval prolongation, the development of hypokalemia may potentiate the risk of ventricular arrhythmias including torsade de pointes. However, clinical data are limited, and the potential significance is unknown. Patients who are receiving systemic or nebulized formulations of beta-2 agonists, high dosages of inhaled beta-2 agonists, or systemic corticosteroid therapy may be at a greater risk of developing hypokalemia.