Imatinibinteractions

CYP3A4 inducers may decrease imatinib mesylate C max and area under curve (AUC). CYP3A4 inhibitors may increase imatinib mesylate C max and AUC. Imatinib mesylate is an inhibitor of CYP3A4 and CYP2D6 which may increase the C max and AUC of other drugs. Patients who require anticoagulation should receive low-molecular weight or standard heparin and not warfarin. Imatinib mesylate tablets delay the clearance of methotrexate when methotrexate is used at high doses (> 500 mg/m 2 ).

7.1 Agents Inducing CYP3A

Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inducers may reduce total exposure of imatinib; consider alternative agents.

7.2 Agents Inhibiting CYP3A

Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inhibitors may result in a significant imatinib exposure increase. Grapefruit juice may also increase plasma concentrations of imatinib; avoid grapefruit juice.

7.3 Interactions

With Drugs Metabolized by CYP3A4 Imatinib mesylate will increase plasma concentration of CYP3A4 metabolized drugs (e.g., triazolo-benzodiazepines, dihydropyridine calcium channel blockers, certain HMG-CoA reductase inhibitors, etc.). Use caution when administering imatinib mesylate tablets with CYP3A4 substrates that have a narrow therapeutic window. Because warfarin is metabolized by CYP2C9 and CYP3A4, use low-molecular weight or standard heparin instead of warfarin in patients who require anticoagulation.

7.4 Interactions

With Drugs Metabolized by CYP2D6 Use caution when administering imatinib mesylate with CYP2D6 substrates that have a narrow therapeutic window.

7.5 Interactions

With Methotrexate Imatinib mesylate tablets delay the clearance of methotrexate and result in sustained methotrexate concentrations when methotrexate is used at high doses (>500 mg/m 2 ). Refer to the prescribing information for methotrexate injection for recommendations on management of methotrexate concentrations.