Drug interactions
Ketoconazole + Terbinafine
Severity: Moderate
Ketoconazole and Terbinafine: 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
Ketoconazole inhibits CYP3A4 and may slightly raise terbinafine concentrations, though terbinafine has many metabolic pathways. Combining two antifungals adds little benefit and increases the potential for additive hepatotoxicity.
What this interaction means in plain words
Ketoconazole and Terbinafine 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.
Ketoconazole belongs to Anti Fungals; Terbinafine belongs to Anti Fungals.
Why it happens
Ketoconazole inhibits CYP3A4 and CYP2C9, reducing part of terbinafine clearance, with additive hepatotoxic potential.
What to do
Avoid routine co-administration of oral antifungals; if used together, monitor liver function tests and for signs of hepatotoxicity.
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 Terbinafine
- Terbinafine + Thioridazine Contraindicated
- Desipramine + Terbinafine Major
- Eliglustat + Terbinafine Major
- Flecainide + Terbinafine Major
- Imipramine + Terbinafine Major
- Maprotiline + Terbinafine Major
Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Ketoconazole with Terbinafine?
MediHelp rates the interaction as moderate. Ketoconazole and Terbinafine 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. Ketoconazole inhibits CYP3A4 and may slightly raise terbinafine concentrations, though terbinafine has many metabolic pathways. Combining two antifungals adds little benefit and increases the potential for additive hepatotoxicity.
How serious is the interaction between Ketoconazole and Terbinafine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid routine co-administration of oral antifungals; if used together, monitor liver function tests and for signs of hepatotoxicity.
What other medicines interact with Terbinafine?
MediHelp also lists interactions of Terbinafine with, for example, Thioridazine, Desipramine, Eliglustat. The full list is on the Terbinafine page.
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