Drug interactions
Ketoconazole + Lumacaftor / ivacaftor
Severity: Major
Ketoconazole and Lumacaftor / ivacaftor: 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
Lumacaftor is a strong CYP3A inducer and may lower ketoconazole exposure, risking antifungal failure. Ketoconazole may also raise ivacaftor levels, though lumacaftor offsets the net inhibitor effect.
What this interaction means in plain words
Ketoconazole and Lumacaftor / ivacaftor 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.
Why it happens
Lumacaftor induces CYP3A4 (and P-gp), accelerating ketoconazole clearance.
What to do
Avoid if possible and use an alternative antifungal. If necessary, monitor for antifungal efficacy and consider drug levels.
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
Frequently asked questions
Can I take Ketoconazole with Lumacaftor / ivacaftor?
MediHelp rates the interaction as major. Ketoconazole and Lumacaftor / ivacaftor 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. Lumacaftor is a strong CYP3A inducer and may lower ketoconazole exposure, risking antifungal failure. Ketoconazole may also raise ivacaftor levels, though lumacaftor offsets the net inhibitor effect.
How serious is the interaction between Ketoconazole and Lumacaftor / ivacaftor?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible and use an alternative antifungal. If necessary, monitor for antifungal efficacy and consider drug levels.
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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