Drug interactions
Ketoconazole + Ritonavir
Severity: Major
Ketoconazole and Ritonavir: major 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 increases ritonavir concentrations, and ritonavir markedly increases ketoconazole exposure. This raises the risk of adverse effects from both drugs, including hepatotoxicity and gastrointestinal effects.
What this interaction means in plain words
Ketoconazole and Ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Ketoconazole belongs to Anti Fungals; Ritonavir belongs to Anti Virals.
Why it happens
Mutual inhibition of CYP3A4 and P-glycoprotein.
What to do
Limit ketoconazole to no more than 200 mg daily with ritonavir and monitor liver function and adverse effects.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
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 Ketoconazole with Ritonavir?
MediHelp rates the interaction as major. Ketoconazole and Ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Ketoconazole increases ritonavir concentrations, and ritonavir markedly increases ketoconazole exposure. This raises the risk of adverse effects from both drugs, including hepatotoxicity and gastrointestinal effects.
How serious is the interaction between Ketoconazole and Ritonavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit ketoconazole to no more than 200 mg daily with ritonavir and monitor liver function and adverse effects.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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