Drug interactions
Isoniazid + Voriconazole
Severity: Moderate
Isoniazid and Voriconazole: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Isoniazid can inhibit CYP2C19 and CYP3A4, which may raise voriconazole concentrations. Higher exposure increases the risk of hepatotoxicity, visual disturbance and neurotoxicity, and both drugs are hepatotoxic.
What this interaction means in plain words
Isoniazid and Voriconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Isoniazid belongs to Anti Bacterial; Voriconazole belongs to Anti Fungals.
Why it happens
Inhibition of CYP2C19 and CYP3A4 by isoniazid reduces voriconazole metabolism, with additive hepatotoxicity.
What to do
Monitor liver function tests and voriconazole trough levels, and reduce voriconazole dose if concentrations are elevated.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Isoniazid
Other interactions of Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Frequently asked questions
Can I take Isoniazid with Voriconazole?
MediHelp rates the interaction as moderate. Isoniazid and Voriconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Isoniazid can inhibit CYP2C19 and CYP3A4, which may raise voriconazole concentrations. Higher exposure increases the risk of hepatotoxicity, visual disturbance and neurotoxicity, and both drugs are hepatotoxic.
How serious is the interaction between Isoniazid and Voriconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor liver function tests and voriconazole trough levels, and reduce voriconazole dose if concentrations are elevated.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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