Drug interactions
Elvitegravir / cobicistat / emtricitabine / tenofovir df + Ketoconazole
Severity: Major
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Ketoconazole: 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
Cobicistat and ketoconazole both inhibit CYP3A4 and each can raise the other's concentrations. Higher ketoconazole exposure raises the risk of hepatotoxicity and QT prolongation, and elvitegravir/cobicistat levels may also increase.
What this interaction means in plain words
Elvitegravir / cobicistat / emtricitabine / tenofovir df and Ketoconazole 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
Mutual CYP3A4 inhibition by cobicistat and ketoconazole reduces clearance of both drugs.
What to do
Do not exceed ketoconazole 200 mg/day and monitor for ketoconazole adverse effects including liver function and QT interval.
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 Elvitegravir / cobicistat / emtricitabine / tenofovir df with Ketoconazole?
MediHelp rates the interaction as major. Elvitegravir / cobicistat / emtricitabine / tenofovir df and Ketoconazole 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. Cobicistat and ketoconazole both inhibit CYP3A4 and each can raise the other's concentrations. Higher ketoconazole exposure raises the risk of hepatotoxicity and QT prolongation, and elvitegravir/cobicistat levels may also increase.
How serious is the interaction between Elvitegravir / cobicistat / emtricitabine / tenofovir df and Ketoconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not exceed ketoconazole 200 mg/day and monitor for ketoconazole adverse effects including liver function and QT interval.
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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