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.

GENERALLY AVOID: Concomitant use of ethanol and a tricyclic antidepressant (TCA) may result altered TCA plasma levels and efficacy, and additive impairment of motor skills, especially driving skills. Acute ethanol ingestion may inhibit TCA metabolism, while chronic ingestion of large amounts of ethanol may induce hepatic TCA metabolism.

MANAGEMENT: Patients should be advised to avoid alcohol during TCA therapy. Alcoholics who have undergone detoxification should be monitored for decreased TCA efficacy. Dosage adjustments may be required.