Drug interactions
Posaconazole + Vemurafenib
Severity: Major
Posaconazole 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
Both drugs prolong the QT interval and posaconazole may raise vemurafenib levels, increasing arrhythmia risk. Vemurafenib also has its own dose-related QT effect.
What this interaction means in plain words
Posaconazole 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.
Posaconazole belongs to Anti Fungals; Vemurafenib belongs to Oncology.
Why it happens
Additive QT prolongation, plus CYP3A4 inhibition by posaconazole increasing vemurafenib exposure.
What to do
Avoid if possible and choose an antifungal with less QT effect. If used together, monitor ECG and electrolytes and correct potassium and magnesium.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Vemurafenib
Frequently asked questions
Can I take Posaconazole with Vemurafenib?
MediHelp rates the interaction as major. Posaconazole 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. Both drugs prolong the QT interval and posaconazole may raise vemurafenib levels, increasing arrhythmia risk. Vemurafenib also has its own dose-related QT effect.
How serious is the interaction between Posaconazole 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 if possible and choose an antifungal with less QT effect. If used together, monitor ECG and electrolytes and correct potassium and magnesium.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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