Drug Interactions between Cotellic and Mekinist

ADJUST DOSING INTERVAL: Food may reduce as well as delay the absorption of trametinib. In study subjects, administration of a single dose of trametinib with a high-fat, high-calorie meal decreased peak plasma concentration (Cmax) and systemic exposure (AUC) by 70% and 24%, respectively, and delayed Tmax by approximately 4 hours compared to administration in the fasted state.

MANAGEMENT: Trametinib should be taken at least 1 hour before or 2 hours after a meal.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme, such as cobimetinib. However, the interaction seems to affect primarily those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability), presumably due to the fact that grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4. Because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of cobimetinib. Grapefruit and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact with these drugs.

The recommended maximum number of medicines in the 'multikinase inhibitors' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'multikinase inhibitors' category:

• Cotellic (cobimetinib)
• Mekinist (trametinib)

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.