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: Alcohol may potentiate the cardiovascular effects of amphetamines. The exact mechanism of interaction is unknown. In one study, concurrent administration of methamphetamine (30 mg intravenously) and ethanol (1 gm/kg orally over 30 minutes) increased heart rate by 24 beats/minute compared to methamphetamine alone. This increases cardiac work and myocardial oxygen consumption, which may lead to more adverse cardiovascular effects than either agent alone. Subjective effects of ethanol were diminished in the eight study subjects, but those of methamphetamine were not affected. The pharmacokinetics of methamphetamine were also unaffected except for a decrease in the apparent volume of distribution at steady state. The interaction was suspected in a case report of a 20-year-old male who experienced retrosternal chest pain shortly after drinking alcohol and taking a double dose of his amphetamine/dextroamphetamine medication (Adderall 15 mg X 2) to stay alert. The patient had no family history of cardiovascular diseases, and his past medical history was remarkable only for ADHD. Prior to the episode, the patient had not taken his medication for weeks and had been drinking whiskey the previous three nights before going to bed. The patient was diagnosed with myocardial infarction likely secondary to amphetamine-induced coronary vasospasm.

MANAGEMENT: Concomitant use of amphetamines and alcohol should be avoided if possible, especially in patients with a history of heart disease.