Imatero Drug Interactions

Observed interactions resulting in a concomitant use not recommended.
Drugs that may decrease Imatinib plasma concentrations: Substances that are inducers of CYP3A4 activity could increase metabolism and decrease Imatinib plasma concentrations. Co-medications that induce CYP3A4 (e.g., Dexamethasone, Phenytoin, Carbamazepine, Rifampicin, Phenobarbital or Hypericum perforatum, also known as St. John's Wort) may significantly reduce exposure to Imatinib. While taking enzyme-inducing anti epileptic drug (EIAEDs) such as Carbamazepine, Phenytoin, Fosphenytoin, Phenobarbital and Primidone. In patients where Rifampin or other CYP3A4 inducers are indicated, alternative therapeutic agents with less enzyme induction potential should be considered.
Other interactions that may affect exposure to Imatinib or other drugs.
Drugs that may increase Imatinib plasma concentrations: Substances that inhibit the cytochrome P450 isoenzyme CYP3A4 activity (e.g. Ketoconazole, Itraconazole, Erythromycin, Clarithromycin) could decrease metabolism and increase Imatinib concentrations. Caution should be taken when administering Imatinib with inhibitors of the CYP3A4 family.
Drugs that may have their plasma concentrations altered by Imatinib: Increasing Simvastatin (CYP3A4 substrate) 2- and 3,5-fold, respectively, indicating and inhibition of the CYP3A4 by Imatinib. Therefore, caution is recommended when administering Imatinib with CYP3A4 substrates with a narrow therapeutic window (e.g. Cyclosporine or Pimozide). Imatinib may increase plasma concentration of other CYP3A4 metabolised drugs (e.g. Triazolobenzodiazepines, dihydropyridine calcium channel blockers, certain HMG-CoA reductase inhibitors, i.e. Statins, etc).
Imatinib also inhibits the CYP2C9 and CYP2C19. PT prolongation was observed following co-administration with Warfarin. When giving Coumarins, short-term PT monitoring is therefore necessary at the start and end of Imatinib therapy and when altering the dosage. Alternatively, the use of low-molecular weight Heparin should be considered.
Imatinib inhibits the cytochrome P450 isoenzyme CYP2D6 activity at concentrations similar to those that affect CYP3A4 activity, Imatinib at 400 mg twice daily had a weak inhibitory effect on CYP2D6-mediated Metoprolol metabolism. Co-administration of Imatinib with CYP2D6 substrates, such as Metoprolol, does not seem to be a risk factor for drug-drug interactions and dose adjustment may not be necessary.