Drug Interactions between Agenerase and lurasidone

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of lurasidone. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice, but has been reported for other CYP450 3A4 inhibitors. When a single 10 mg dose of lurasidone was administered with the potent CYP450 3A4 inhibitor ketoconazole (400 mg/day for 5 days), lurasidone peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 6.9- and 9.0-fold, respectively, compared to administration alone. The AUC of lurasidone's active metabolite increased by 6-fold. Another potent CYP450 3A4 inhibitor, posaconazole, has been reported to increase lurasidone AUC by approximately 4.5-fold. When a single 20 mg dose of lurasidone was administered with the moderate CYP450 3A4 inhibitor diltiazem (extended release formulation 240 mg/day for 5 days), lurasidone Cmax and AUC increased by 2.1- and 2.2-fold, respectively, while the AUC of the active metabolite increased by 2.4-fold. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

GENERALLY AVOID: Alcohol may potentiate some of the central nervous system and hypotensive effects of lurasidone. Use in combination may result in increased sedation, dizziness, hypotension, and impairment of judgment, thinking, and psychomotor skills.

ADJUST DOSING INTERVAL: Food increases the oral bioavailability of lurasidone. According to the product labeling, lurasidone mean Cmax and AUC were increased approximately 3-fold and 2-fold, respectively, when administered with food relative to under fasting conditions. Lurasidone AUC was not affected by meal size (in the range of 350 to 1000 calories) or fat content. In clinical studies, lurasidone was administered with food.

MANAGEMENT: Patients treated with lurasidone should avoid consumption of grapefruit and grapefruit juice as well as alcohol. Lurasidone should be taken with food (at least 350 calories).

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.