Drug Interaction Report

GENERALLY AVOID: Concomitant use of cocaine with sympathomimetic agents such as epinephrine and phenylephrine may lead to additive cardiovascular effects. The proposed mechanism involves increased circulating catecholamines and increased activity of the sympathetic nervous system. Locally administered cocaine and epinephrine have been used in combination during septal surgery; however, concerns regarding cardiovascular side effects have been raised. Myocardial ischemia, myocardial infarction, and ventricular arrhythmias have been reported following coadministration of topical intranasal cocaine with epinephrine and phenylephrine during nasal and sinus surgery. Cases documenting the development of arrhythmias after the nasal application of cocaine and epinephrine 25%-0.18% topical paste have also been reported in 2 children and one adult receiving general anesthesia. However, the dosage of cocaine administered in these cases was above the maximum recommended dose in fit adults (1.5 mg/kg).

MANAGEMENT: Concomitant use of cocaine with sympathomimetic agents should be avoided. If coadministration is required, prolonged vital sign and ECG monitoring may be necessary.

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.