Drug Interaction Report

Voriconazole may increase the blood levels and effects of cycloSPORINE. You may need a dose adjustment if you have been taking cycloSPORINE and are starting treatment with voriconazole. Contact your doctor if your condition changes or if you experience increased side effects such as nausea, vomiting, diarrhea, abdominal pain, dizziness, fatigue, headache, tremors, seizures, fever, sore throat, unusual bruising or bleeding, and increased or decreased urination. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Using cycloSPORINE together with letermovir may increase the blood levels of both medications. Talk to your doctor if you have any questions or concerns. You may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects such as nausea, vomiting, diarrhea, abdominal pain, dizziness, fatigue, headache, tremors, seizures, fever, sore throat, unusual bruising or bleeding, and increased or decreased urination. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR CLOSELY: Coadministration with letermovir may significantly decrease the plasma concentrations and efficacy of voriconazole. The proposed mechanism is induction of CYP450 2C9 and/or 2C19, isoenzymes primarily responsible for the metabolic clearance of voriconazole. According to the product labeling, voriconazole peak plasma concentration (Cmax), systemic exposure (AUC) and concentration at 12 hours post-dose (C12hr) decreased by an average of 39%, 44% and 51%, respectively, when voriconazole 200 mg orally twice daily was coadministered with letermovir 480 mg orally once daily. Subtherapeutic levels of voriconazole may occur.

MANAGEMENT: Close clinical and laboratory monitoring are advised if letermovir is used concomitantly with voriconazole. Some authorities recommend avoiding this combination. Dosage adjustments may be appropriate for voriconazole whenever letermovir is added to or withdrawn from therapy.

Grapefruit and grapefruit juice can increase the levels of cycloSPORINE in your body and should generally not be consumed during treatment. High blood levels of cycloSPORINE can lead to increased risk of serious side effects on kidney, liver, and nervous system functions. If you regularly consume grapefruits or grapefruit juice, you should be monitored for side effects and/or changes in cycloSPORINE levels. However, do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor. You should also take cycloSPORINE on a consistent schedule with regard to time of day and relation to meals. Let your doctor know if you experience fever, rash, nausea, vomiting, abdominal pain, loss of appetite, dark urine, jaundice (yellowing of the skin or eyes), decreased urination, excessive thirst, swelling, weight gain, dizziness, fatigue, weakness, headache, blurred vision, numbness/burning/tingling in the hand and feet, tremors, or convulsions, as they may be symptoms caused by excessive effects of cycloSPORINE.

You may experience reduced absorption of voriconazole in the presence of food. Take voriconazole on an empty stomach 1 hour before or 2 hours after a meal unless otherwise directed by your doctor. This will make it easier for your body to absorb the medication.