Adverse reactions identified from the postmarketing use of the combination regimen of Zortress and cyclosporine that are not specific to any one transplant indication include angioedema [ s ee Warnings and Precautions (5. 8 ) ] , erythroderma, leukocytoclastic vasculitis, pancreatitis, pulmonary alveolar proteinosis, and pulmonary embolism. There have also been reports of male infertility with mTOR inhibitors, including Zortress [ s ee Warnings and Precautions ( 5.1 8 ) ] .
Everolimus is mainly metabolized by CYP3A4 in the liver and to some extent in the intestinal wall and is a substrate for the multidrug efflux pump, P-glycoprotein (P-gp). Therefore, absorption and subsequent elimination of systemically absorbed everolimus may be influenced by medicinal products that affect CYP3A4 and/or P-gp. Concurrent treatment with strong inhibitors (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, telithromycin, ritonavir, boceprevir, telaprevir) and inducers (e.g., rifampin, rifabutin) of CYP3A4 is not recommended. Inhibitors of P-gp (e.g., digoxin, cyclosporine) may decrease the efflux of everolimus from intestinal cells and increase everolimus blood concentrations. In vitro , everolimus was a competitive inhibitor of CYP3A4 and of CYP2D6, potentially increasing the concentrations of medicinal products eliminated by these enzymes. Thus, caution should be exercised when coadministering Zortress with CYP3A4 and CYP2D6 substrates with a narrow therapeutic index [ s ee Dosage and Administration ( 2. 3 ) ] .
All in vivo interaction studies were conducted without concomitant cyclosporine. Pharmacokinetic interactions between Zortress and concomitantly administered drugs are discussed below. Drug interaction studies have not been conducted with drugs other than those described below.
The steady-state Cmax and area under the curve (AUC) estimates of everolimus were significantly increased by coadministration of single dose cyclosporine [ s ee Clinical Pharmaco logy (12. 5 )] . Dose adjustment of Zortress might be needed if the cyclosporine dose is altered [ s ee Dosage and Administration ( 2. 3)] . Zortress had a clinically minor influence on cyclosporine pharmacokinetics in transplant patients receiving cyclosporine (Neoral).
Multiple-dose ketoconazole administration to healthy volunteers significantly increased single dose estimates of everolimus Cmax , AUC, and half-life. It is recommended that strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, telithromycin, ritonavir, boceprevir, telaprevir) should not be coadministered with Zortress [ s ee Warnings and Precautions ( 5. 1 4 ), Clinical Pharmaco logy (12. 5 )] .
Multiple-dose erythromycin administration to healthy volunteers significantly increased single dose estimates of everolimus Cmax , AUC, and half-life. If erythromycin is coadministered, everolimus blood concentrations should be monitored and a dose adjustment made as necessary [ s ee Clinical Pharmaco logy (12. 5 )] .
Multiple-dose verapamil administration to healthy volunteers significantly increased single dose estimates of everolimus Cmax and AUC. Everolimus half-life was not changed. If verapamil is coadministered, everolimus blood concentrations should be monitored and a dose adjustment made as necessary [ s ee Clinical Pharmaco logy (12. 5 ) ] .
Single-dose administration of Zortress with either atorvastatin or pravastatin to healthy subjects did not influence the pharmacokinetics of atorvastatin, pravastatin and everolimus, as well as total HMG-CoA reductase bioreactivity in plasma to a clinically relevant extent. However, these results cannot be extrapolated to other HMG-CoA reductase inhibitors. Patients should be monitored for the development of rhabdomyolysis and other adverse reactions as described in the respective labeling for these products.
Due to an interaction with cyclosporine, clinical studies of Zortress with cyclosporine conducted in kidney transplant patients strongly discouraged patients with receiving HMG-CoA reductase inhibitors such as simvastatin and lovastatin [ s ee Warnings and Precautions ( 5.1 1 )] .
Pretreatment of healthy subjects with multiple-dose rifampin followed by a single dose of Zortress increased everolimus clearance and decreased the everolimus Cmax and AUC estimates. Combination with rifampin is not recommended [ s ee Warnings and Precautions ( 5.1 4 ) , Clinical Pharmacology (12. 5 )] .
Single-dose administration of midazolam to healthy volunteers following administration of multiple-dose Zortress indicated that everolimus is a weak inhibitor of CYP3A4/5. Dose adjustment of midazolam or other CYP3A4/5 substrates is not necessary when Zortress is coadministered with midazolam or other CYP3A4/5 substrates [ s ee Clinical Pharmacology (12. 5 )] .
Moderate inhibitors of CYP3A4 and P-gp may increase everolimus blood concentrations (e.g., fluconazole; macrolide antibiotics; nicardipine, diltiazem; nelfinavir, indinavir, amprenavir). Inducers of CYP3A4 may increase the metabolism of everolimus and decrease everolimus blood concentrations (e.g., St. John’s Wort [Hypericum perforatum ]; anticonvulsants: carbamazepine, phenobarbital, phenytoin; efavirenz, nevirapine).
Coadministration of everolimus and depot octreotide increased octreotide Cmin by approximately 50%.
There is little to no pharmacokinetic interaction of tacrolimus on everolimus, and consequently, dose adjustment of Zortress is not necessary when Zortress is coadministered with tacrolimus.
Based on animal studies and the mechanism of action [see Clinical Pharmacology (12.1)] , Zortress can cause fetal harm when administered to a pregnant woman. There are limited case reports of Zortress use in pregnant women; however, these reports are insufficient to inform a drug associated risk of adverse developmental outcomes. Reproductive studies in animals have demonstrated that everolimus was maternally toxic in rabbits and caused embryo-fetal toxicities in rats and rabbits, at exposures near or below those achieved in human transplant patients. Advise pregnant women of the potential risk to a fetus.
The background risk of major birth defects and miscarriage for the indicated population is unknown; however, in the U.S. general population, the estimated background risk of major birth defects is 2% to 4% and of miscarriage is 15% to 20% of clinically recognized pregnancies.
Everolimus crossed the placenta and was toxic to the conceptus.
Everolimus administered daily to pregnant rats by oral gavage at 0.1 mg/kg (approximately one tenth the exposure in humans administered the lowest starting dose of 0.75 mg twice daily), from before mating through organogenesis, resulted in increased preimplantation loss and embryonic resorptions. These effects occurred in the absence of maternal toxicities.
Everolimus administered daily by oral gavage to pregnant rabbits during organogenesis resulted in abortions, maternal toxicity and lethality, and increased fetal resorptions. At these doses, exposure to everolimus (AUC) was approximately one-tenth, one-half, and one and one-half fold the exposures in humans administered the starting clinical dose, respectively.
In a pre- and post-natal development study in rats, animals were dosed from implantation through lactation. At a dose of 0.1 mg/kg (0.6 mg/m2), there were no adverse effects on delivery and lactation or signs of maternal toxicity; however, there were reductions in body weight (up to 9% reduction) and in survival of offspring (~5%). There were no drug-related effects on the developmental parameters (morphological development, motor activity, learning, or fertility assessment) in the offspring.
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