Drug Interactions between fenfluramine and Lonsurf

GENERALLY AVOID: Alcohol may potentiate the central nervous system and cardiovascular effects of centrally-acting appetite suppressants. 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.

MANAGEMENT: Concomitant use of centrally-acting appetite suppressants and alcohol should be avoided if possible, especially in patients with a history of cardiovascular disease. Patients should be counselled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

ADJUST DOSING INTERVAL: Administration of trifluridine-tipiracil with a standardized high-fat, high-calorie meal has been shown to decrease trifluridine peak plasma concentration (Cmax) as well as tipiracil Cmax and systemic exposure (AUC) by approximately 40% compared to administration in a fasting state in patients with cancer given a single 35 mg/m2 dose. No change in trifluridine AUC was observed.

MANAGEMENT: Based on the observed correlation between increases in the Cmax of trifluridine and decreases in neutrophil counts, trifluridine-tipiracil should be taken within one hour after completion of the morning and evening meals.