Drug interactions
Ketoconazole + Rifapentine
Severity: Major
Ketoconazole and Rifapentine: 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
Rifapentine is an inducer of CYP3A4 and can markedly reduce ketoconazole concentrations, risking antifungal failure. Rifamycins can also be affected by azoles, though the main concern is loss of ketoconazole effect.
What this interaction means in plain words
Ketoconazole and Rifapentine 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; Rifapentine belongs to Anti Bacterial.
Why it happens
Rifapentine induces CYP3A4 and other metabolic enzymes, increasing ketoconazole clearance.
What to do
Avoid the combination if possible and choose an alternative antifungal. If it must be used, monitor clinical response and liver function closely.
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 Rifapentine
- Ledipasvir-sofosbuvir + Rifapentine Contraindicated
- Lorlatinib + Rifapentine Contraindicated
- Lurasidone + Rifapentine Contraindicated
- Ranolazine + Rifapentine Contraindicated
- Rifapentine + Sofosbuvir-velpatasvir Contraindicated
- Rifapentine + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Ketoconazole with Rifapentine?
MediHelp rates the interaction as major. Ketoconazole and Rifapentine 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. Rifapentine is an inducer of CYP3A4 and can markedly reduce ketoconazole concentrations, risking antifungal failure. Rifamycins can also be affected by azoles, though the main concern is loss of ketoconazole effect.
How serious is the interaction between Ketoconazole and Rifapentine?
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 the combination if possible and choose an alternative antifungal. If it must be used, monitor clinical response and liver function closely.
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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