Fluconazole and Voriconazole interaction
Fluconazole and Voriconazole: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Fluconazole label · effective 2026-04-02
Voriconazole Avoid concomitant administration of voriconazole and fluconazole.
There is no information regarding cross-hypersensitivity between fluconazole and other azole antifungal agents.
Caution should be used in prescribing fluconazole to patients with hypersensitivity to other azoles.
Coadministration of other drugs known to prolong the QT interval and which are metabolized via the enzyme CYP3A4 such as erythromycin, pimozide, and quinidine are contraindicated in patients receiving fluconazole.
Monitoring for adverse events and toxicity related to voriconazole is recommended; especially, if voriconazole is started within 24 h after the last dose of fluconazole.
From the Voriconazole label · effective 2026-06-02
Fluconazole (CYP2C9, CYP2C19 and CYP3A4 Inhibition) Significantly Increased Avoid concomitant administration of voriconazole and fluconazole.
There is no information regarding cross-sensitivity between voriconazole and other azole antifungal agents.
Refer to the prescribing information for other azole antifungal agents.
Monitoring for adverse reactions and toxicity related to voriconazole is started within 24 hours after the last dose of fluconazole.
Other HIV Protease Inhibitors (CYP3A4 Inhibition) In Vivo Studies Showed No Significant Effects of Indinavir on Voriconazole Exposure In Vitro Studies Demonstrated Potential for Inhibition of Voriconazole Metabolism (Increased Plasma Exposure) No dosage adjustment in the voriconazole dosage needed for concomitant administration with indinavir.
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.