Drug interactions
Primidone + Terbinafine
Severity: Moderate
Primidone 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
Primidone, and its active metabolite phenobarbital, induce hepatic enzymes and may lower terbinafine exposure. This could reduce antifungal efficacy, particularly in onychomycosis or deep dermatophyte infections.
What this interaction means in plain words
Primidone 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.
Primidone belongs to Central Nervous System; Terbinafine belongs to Anti Fungals.
Why it happens
Enzyme induction by primidone/phenobarbital increases the CYP-mediated metabolism of terbinafine.
What to do
Monitor clinical response to terbinafine and consider a higher dose or longer course if response is inadequate. Consider an alternative antifungal if the response is poor.
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 Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Primidone with Terbinafine?
MediHelp rates the interaction as moderate. Primidone 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. Primidone, and its active metabolite phenobarbital, induce hepatic enzymes and may lower terbinafine exposure. This could reduce antifungal efficacy, particularly in onychomycosis or deep dermatophyte infections.
How serious is the interaction between Primidone 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: Monitor clinical response to terbinafine and consider a higher dose or longer course if response is inadequate. Consider an alternative antifungal if the response is poor.
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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