Drug Interaction Report

GENERALLY AVOID: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of lumateperone, which is metabolized by the isoenzyme in vitro. In a drug interaction study, the strong CYP450 3A4 inducer rifampin decreased lumateperone peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 80% and 97%, respectively. The interaction has not been studied with other, less potent inducers.

MONITOR CLOSELY: Central nervous system depressant or toxic effects may be additively or synergistically increased in patients taking lumateperone with certain other drugs (such as other CNS-active agents or efavirenz) that cause these effects, especially in elderly or debilitated patients.

MANAGEMENT: Coadministration of CYP450 3A4 inducers with lumateperone should be avoided.

GENERALLY AVOID: Coadministration with potent or moderate inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of encorafenib, which is primarily metabolized by the isoenzyme. When a single 50 mg dose of encorafenib (equivalent to 0.1 times the recommended dose) was administered with posaconazole, a potent CYP450 3A4 inhibitor, encorafenib peak plasma concentration (Cmax) increased by 68% and systemic exposure (AUC) increased by 3-fold. When the same dose of encorafenib was administered with diltiazem, a moderate CYP450 3A4 inhibitor, encorafenib Cmax increased by 45% and AUC increased by 2-fold. Increased exposure to encorafenib may increase the risk of serious and life-threatening adverse effects such as hemorrhage, uveitis, QT prolongation, hepatotoxicity, dermatologic reactions, and new malignancies.

MANAGEMENT: Concomitant use of encorafenib with grapefruit or grapefruit juice should generally be avoided. If coadministration is required, the manufacturer recommends reducing the encorafenib dose to one-third of the dose used prior to addition of a potent CYP450 3A4 inhibitor or one-half of the dose used prior to addition of a moderate CYP450 3A4 inhibitor. After the inhibitor has been discontinued for 3 to 5 elimination half-lives, the encorafenib dose that was taken prior to initiating the inhibitor may be resumed.

GENERALLY AVOID: Grapefruit and grapefruit juice may increase the plasma concentrations of lumateperone. 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 but has been reported for other CYP450 3A4 inhibitors. In a drug interaction study, the strong CYP450 3A4 inhibitor itraconazole increased lumateperone peak plasma concentration (Cmax) and systemic exposure (AUC) approximately 3.5- and 4-fold, respectively, while diltiazem (a moderate CYP450 3A4 inhibitor) increased lumateperone Cmax and AUC approximately 2- and 2.5-fold, respectively. 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.

When administered with a high-fat meal, lumateperone Cmax decreased by 33% while its AUC increased by 9% and its median time to peak plasma concentration (Tmax) was delayed by about 1 hour.

MANAGEMENT: Lumateperone should be administered with food. Coadministration of grapefruit or grapefruit juice with lumateperone should be avoided.