Drug interactions
Ketoconazole + Vemurafenib
Severity: Major
Ketoconazole and Vemurafenib: 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 may raise vemurafenib concentrations, increasing adverse effects such as QT prolongation, rash and arthralgia. Vemurafenib itself prolongs QT, so higher exposure is a concern.
What this interaction means in plain words
Ketoconazole and Vemurafenib 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; Vemurafenib belongs to Oncology.
Why it happens
Ketoconazole inhibits CYP3A4, a metabolic pathway of vemurafenib, and both agents prolong QT.
What to do
Avoid strong CYP3A4 inhibitors where possible. If necessary, monitor ECG and electrolytes and consider vemurafenib dose reduction for toxicity.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Ketoconazole and Vemurafenib, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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 Vemurafenib
Frequently asked questions
Can I take Ketoconazole with Vemurafenib?
MediHelp rates the interaction as major. Ketoconazole and Vemurafenib 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 may raise vemurafenib concentrations, increasing adverse effects such as QT prolongation, rash and arthralgia. Vemurafenib itself prolongs QT, so higher exposure is a concern.
How serious is the interaction between Ketoconazole and Vemurafenib?
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 strong CYP3A4 inhibitors where possible. If necessary, monitor ECG and electrolytes and consider vemurafenib dose reduction for toxicity.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
