Drug interactions
Ritonavir + Terbinafine
Severity: Minor
Ritonavir 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
Terbinafine is a strong CYP2D6 inhibitor, which can raise concentrations of CYP2D6 substrates; ritonavir is partly a CYP2D6 substrate, though its main metabolism is via CYP3A4. Ritonavir may modestly raise terbinafine levels through CYP3A4 inhibition, and the overall effect is likely modest.
What this interaction means in plain words
Ritonavir 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.
Ritonavir belongs to Anti Virals; Terbinafine belongs to Anti Fungals.
Why it happens
Terbinafine inhibits CYP2D6 and ritonavir inhibits CYP3A4, which may modestly reduce clearance of each other.
What to do
No routine adjustment is needed; monitor for adverse effects of either drug, such as gastrointestinal upset or hepatic effects, and check liver tests if symptoms arise.
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 Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Terbinafine?
MediHelp rates the interaction as minor. Ritonavir 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. Terbinafine is a strong CYP2D6 inhibitor, which can raise concentrations of CYP2D6 substrates; ritonavir is partly a CYP2D6 substrate, though its main metabolism is via CYP3A4. Ritonavir may modestly raise terbinafine levels through CYP3A4 inhibition, and the overall effect is likely modest.
How serious is the interaction between Ritonavir 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 adjustment is needed; monitor for adverse effects of either drug, such as gastrointestinal upset or hepatic effects, and check liver tests if symptoms arise.
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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