7 DRUG INTERACTIONS
Sirolimus is known to be a substrate for both cytochrome P-450 3A4 (CYP3A4) and p-glycoprotein (P-gp). Inducers of CYP3A4 and P-gp may decrease sirolimus concentrations whereas inhibitors of CYP3A4 and P-gp may increase sirolimus concentrations.
7.1 Use with Cyclosporine
Cyclosporine, a substrate and inhibitor of CYP3A4 and P-gp, was demonstrated to increase sirolimus concentrations when co-administered with sirolimus. In order to diminish the effect of this interaction with cyclosporine, it is recommended that Rapamune be taken 4 hours after administration of cyclosporine oral solution (MODIFIED) and/or cyclosporine capsules (MODIFIED). If cyclosporine is withdrawn from combination therapy with Rapamune, higher doses of Rapamune are needed to maintain the recommended sirolimus trough concentration ranges [see Dosage and Administration (2.2), Clinical Pharmacology (12.3)].
7.2 Strong Inducers and Strong Inhibitors of CYP3A4 and P-gp
Avoid concomitant use of sirolimus with strong inducers (e.g., rifampin, rifabutin) and strong inhibitors (e.g., ketoconazole, voriconazole, itraconazole, erythromycin, telithromycin, clarithromycin) of CYP3A4 and P-gp. Alternative agents with lesser interaction potential with sirolimus should be considered [see Warnings and Precautions (5.20), Clinical Pharmacology (12.3)].
7.3 Grapefruit Juice
Because grapefruit juice inhibits the CYP3A4-mediated metabolism of sirolimus, it must not be taken with or be used for dilution of Rapamune [see Dosage and Administration (2.9), Drug Interactions (7.3), Clinical Pharmacology (12.3)].
7.4 Weak and Moderate Inducers or Inhibitors of CYP3A4 and P-gp
Exercise caution when using sirolimus with drugs or agents that are modulators of CYP3A4 and P-gp. The dosage of Rapamune and/or the co-administered drug may need to be adjusted [see Clinical Pharmacology (12.3)].
- Drugs that could increase sirolimus blood concentrations:
Bromocriptine, cimetidine, cisapride, clotrimazole, danazol, diltiazem, fluconazole, protease inhibitors (e.g., HIV and hepatitis C that include drugs such as ritonavir, indinavir, boceprevir, and telaprevir), metoclopramide, nicardipine, troleandomycin, verapamil
- Drugs and other agents that could decrease sirolimus concentrations:
Carbamazepine, phenobarbital, phenytoin, rifapentine, St. John's Wort (Hypericum perforatum)
- Drugs with concentrations that could increase when given with Rapamune: