Methadone and Voriconazole interaction
Methadone and Voriconazole: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Methadone (METHADOSE) label · effective 2026-04-27
Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), fluconazole, fluvoxamine, some selective serotonin reuptake inhibitors (SSRIs) (e.g., sertraline, fluvoxamine) Inducers of CYP3A4, CYP2B6, CYP2C19, or CYP2C9 Clinical Impact: The concomitant use of methadone and CYP3A4, CYP2B6,…
Inhibitors of CYP3A4, CYP2B6, CYP2C19, CYP2C9, or CYP2D6 Clinical Impact: Methadone undergoes hepatic N-demethylation by several cytochrome P450 (CYP) isoforms, including CYP3A4, CYP2B6, CYP2C19, CYP2C9, and CYP2D6.
From the Voriconazole label · effective 2026-06-02
Methadone Results based on in vivo clinical study following repeat oral dosing with 400 mg every 12 hours for 1 day, then 200 mg every 12 hours for 4 days voriconazole to subjects receiving a methadone maintenance dose (30–100 mg every 24 hours) (CYP3A4 Inhibition) Increased Increased plasma concentrations of methadone have been associated with toxicity including…
Frequent monitoring for adverse reactions and toxicity related to methadone is recommended when concomitantly administered with voriconazole.
Dose reduction of methadone may be needed.
Fentanyl (CYP3A4 Inhibition) Increased Reduction in the dose of fentanyl and other long-acting opiates metabolized by CYP3A4 should be considered when concomitantly administered with voriconazole.
Extended and frequent monitoring for opiate-associated adverse reactions may be necessary .
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.