Drug Interaction Report

ADJUST DOSE: Concomitant use with potent CYP450 3A4 inhibitors may increase the systemic concentrations and effects of zuranolone. The proposed mechanism is inhibition of the CYP450 3A4-mediated metabolism of zuranolone, which is primarily metabolized by this isoenzyme. Drug interaction studies have shown that coadministration with the potent CYP450 3A4 inhibitor itraconazole increased the systemic exposure (AUC) and peak plasma concentration (Cmax) by approximately 60% and 25%, respectively. Increased exposure to zuranolone may increase the risk of CNS-related adverse effects such as somnolence, confusion, dizziness and gait disturbances.

MANAGEMENT: If concomitant use with a potent CYP450 3A4 inhibitor is required, the manufacturer recommends that the dosage of zuranolone be reduced to 30 mg once daily for 14 days. No dosage adjustment is advised when used in combination with moderate CYP450 3A4 inhibitors.

GENERALLY AVOID: Administration with a high-fat meal may decrease the oral bioavailability of amprenavir. The mechanism is unknown. In healthy volunteers, consumption of a standardized high-fat meal decreased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir (1200 mg single oral dose) by 36% and 21%, respectively, compared to administration in the fasted state. The time to reach Cmax (Tmax) was increased 44% following a high-fat meal.

Grapefruit juice does not appear to significantly affect the pharmacokinetics of amprenavir. In 12 healthy volunteers, administration with grapefruit juice (200 mL) decreased the mean peak plasma concentration (Cmax) of amprenavir (1200 mg single oral dose) by 22% compared to water. The median time to reach Cmax (Tmax) was prolonged from 0.75 to 1.13 hours. These pharmacokinetic changes are not thought to be clinically significant, since antiretroviral response is more closely associated with systemic exposure (AUC) and trough plasma concentration (Cmin), which were not affected in the study.

MANAGEMENT: Amprenavir may be taken with or without food, but should not be taken with a high-fat meal.

ADJUST DOSING INTERVAL: Food enhances the oral bioavailability of zuranolone. When administered with a low-fat meal (e.g., 400 to 500 calories, 25% fat), zuranolone peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 3.5- and 1.8-fold, respectively, compared to administration under fasted conditions. Zuranolone was administered with food in the premarketing study population. The efficacy of zuranolone when administered in the fasted state is unknown.

GENERALLY AVOID: Concomitant use of zuranolone with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence, confusion, dizziness, and gait disturbance.

MANAGEMENT: Zuranolone must be administered with fat-containing food (e.g., 400 to 1,000 calories, 25% to 50% fat) according to the manufacturer. Patients should also be advised to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until at least 12 hours after administration of zuranolone.