Drug interactions
Efavirenz + Encorafenib
Severity: Major
Efavirenz and Encorafenib: 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
Efavirenz may lower encorafenib exposure, reducing antitumour activity. Both drugs can also prolong the QT interval, so combined use raises arrhythmia risk.
What this interaction means in plain words
Efavirenz and Encorafenib 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.
Efavirenz belongs to Anti Virals; Encorafenib belongs to Oncology.
Why it happens
Efavirenz induces CYP3A4, which metabolizes encorafenib, and both drugs have additive QTc-prolonging effects.
What to do
Use an alternative antiretroviral without enzyme-inducing properties where possible. If unavoidable, monitor ECG and electrolytes and assess for reduced cancer response.
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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Other interactions of Encorafenib
Frequently asked questions
Can I take Efavirenz with Encorafenib?
MediHelp rates the interaction as major. Efavirenz and Encorafenib 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. Efavirenz may lower encorafenib exposure, reducing antitumour activity. Both drugs can also prolong the QT interval, so combined use raises arrhythmia risk.
How serious is the interaction between Efavirenz and Encorafenib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use an alternative antiretroviral without enzyme-inducing properties where possible. If unavoidable, monitor ECG and electrolytes and assess for reduced cancer response.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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