Drug Interactions between Adderall and propranolol

ADJUST DOSING INTERVAL: The bioavailability of propranolol may be enhanced by food.

MANAGEMENT: Patients may be instructed to take propranolol at the same time each day, preferably with or immediately following meals.

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.

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.

ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers. The exact mechanism of interaction is unknown. In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively. The elimination half-life increased by 44%. Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone. However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments. The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

MANAGEMENT: It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours. Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.