Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with imatinib may increase the plasma concentrations of drugs that are substrates of CYP450 2C9, 2D6 and/or 3A4. The mechanism is decreased clearance due to inhibition of these isoenzymes by imatinib. According to the manufacturer, imatinib increased the mean peak plasma concentration (Cmax) and systemic exposure (AUC) of simvastatin, a sensitive CYP450 3A4 substrate, by 2- and 3.5-fold, respectively. Data for other substrates are limited, although human liver microsome studies indicate that imatinib is a potent competitive inhibitor of all three isoenzymes.

MANAGEMENT: Caution is advised when imatinib is used concomitantly with drugs that undergo metabolism by CYP450 2C9, 2D6 and/or 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever imatinib is added to or withdrawn from therapy.

Grapefruit juice may increase the blood levels of certain medications such as imatinib. You should avoid consumption of grapefruit and grapefruit juice during treatment with imatinib. However, if you have been regularly consuming grapefruit or grapefruit juice with the medication, then it is advisable for you to talk with your doctor before changing the amounts of these products in your diet, as this may alter the effects of your medication. Contact your doctor if your condition changes or you experience increased side effects. Orange juice is not expected to interact.