Drug interactions
Efavirenz + Terbinafine
Severity: Minor
Efavirenz and Terbinafine: minor 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
Efavirenz induces CYP3A4 and may reduce terbinafine exposure to some degree. Because terbinafine is cleared by many pathways, the effect is likely modest, but reduced antifungal response is possible.
What this interaction means in plain words
Efavirenz and Terbinafine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Efavirenz belongs to Anti Virals; Terbinafine belongs to Anti Fungals.
Why it happens
Efavirenz induces CYP3A4 and other CYP enzymes that contribute to terbinafine metabolism.
What to do
No routine dose change is needed; monitor mycological and clinical response and extend therapy if needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Efavirenz with Terbinafine?
MediHelp rates the interaction as minor. Efavirenz and Terbinafine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Efavirenz induces CYP3A4 and may reduce terbinafine exposure to some degree. Because terbinafine is cleared by many pathways, the effect is likely modest, but reduced antifungal response is possible.
How serious is the interaction between Efavirenz and Terbinafine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine dose change is needed; monitor mycological and clinical response and extend therapy if needed.
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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