Does Voriconazole Interact with Letermovir?
CDI records a contraindicated classification for Voriconazole and Letermovir. The stored summary is: Table 6: Effect of Other Drugs on Voriconazole Pharmacokinetics [see Clinical Pharmacology (12.3) ] Drug/Drug Class (Mechanism of Interaction by the Drug) Voriconazole Plasma Exposure (C max and AUC τ after 200 mg every 12 hours) Recommendations for Voriconazole Dosage Adjustment/Comments Rifampin and Rifabutin (CYP450 Induction) Significantly Reduced Contraindicated Efavirenz (400 mg every 24 hours) (CYP450 Induction) Significantly Reduced Contraindicated High-dose Ritonavir (400 mg every 12 hours) (CYP450 Induction) Significantly Reduced Contraindicated Low-dose Ritonavir (100 mg every 12 hours) (CYP450 Induction) Reduced Coadministration of voriconazole and low-dose ritonavir (100 mg every 12 hours) should be avoided, unless an assessment of the benefit/risk to the patient justifies the use of voriconazole Carbamazepine (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Long Acting Barbiturates (e.g., phenobarbital, mephobarbital) (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Phenytoin (CYP450 Induction) Significantly Reduced Increase voriconazole maintenance dose from 4 mg/kg to 5 mg/kg IV every12 hours Letermovir (CYP2C9/2C19 Induction) Reduced If concomitant administration of voriconazole with letermovir cannot be avoided, monitor for reduced effectiveness of voriconazole. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.
- Severity
- Contraindicated
- Voriconazole Class
- Azole Antifungal
- Letermovir Class
- Cytomegalovirus DNA Terminase Complex Inhibitor
- Management
- Do not take together
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Voriconazole and your doctor is considering prescribing Letermovir (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask about alternative medications that do not interact with your current regimen
- Ask how frequently you should be monitored while these are co-prescribed
- Never stop or change either medication without first consulting your healthcare provider