Drug Interactions between ezogabine and taletrectinib

GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of taletrectinib. The proposed mechanism for the interaction 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. In a clinical study, taletrectinib peak plasma concentration (Cmax) increased by 1.8-fold and systemic exposure (AUC) increased by 3.3-fold following concomitant administration of itraconazole, a potent CYP450 3A inhibitor. According to the product labeling, administration of taletrectinib with a moderate CYP450 3A inhibitor is predicted to increase taletrectinib Cmax and AUC by up to 1.5- and 2.6-fold, respectively. Increased exposure to taletrectinib may increase the risk and/or severity of adverse effects such as hepatotoxicity with liver enzyme elevations, lung toxicities, QT prolongation, hyperuricemia, myalgia with creatine phosphokinase elevation, and skeletal fractures.

ADJUST DOSING INTERVAL: Coadministration with high-fat food (1000 calories, 50% fat) increased taletrectinib Cmax and AUC by 1.5-fold, and the predicted increase in the QTc interval is 20.5 msec.

MANAGEMENT: The manufacturer recommends avoiding food or drink containing grapefruit during treatment with taletrectinib. In addition, taletrectinib should be administered on an empty stomach at about the same time each day, at least 2 hours before or 2 hours after food intake.

GENERALLY AVOID: Alcohol may increase the plasma concentrations of ezogabine. In a study of healthy volunteers, the administration of ezogabine 200 mg in combination with ethanol 1g/kg (5 standard alcohol drinks) over 20 minutes resulted in an increase in the ezogabine peak plasma concentration (Cmax) and systemic exposure (AUC) by 23% and 37%, respectively.

Food does not significantly affect the bioavailability of ezogabine. According to the product labeling, high-fat food does not affect the extent to which ezogabine is absorbed, but increases peak plasma concentration (Cmax) by approximately 38% and delays the time to reach peak concentration (Tmax) by 0.75 hour.

MANAGEMENT: In general, alcohol consumption should be avoided or limited during treatment with CNS-depressant agents. Patients should be advised of the potential for increased dose-related adverse reactions of ezogabine (e.g., dizziness, somnolence, nausea, constipation, urinary retention, blurred vision, memory impairment, tremor) when taken with alcohol, and to avoid hazardous activities that require mental alertness and motor coordination until they know how the medication affects them. Ezogabine can be taken with or without food.