Drug interactions
Efavirenz + Elvitegravir / cobicistat / emtricitabine / tenofovir df
Severity: Contraindicated
Efavirenz and Elvitegravir / cobicistat / emtricitabine / tenofovir df: contraindicated 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
This single-tablet regimen is a complete HIV treatment and is not intended to be combined with other antiretrovirals. Efavirenz induces CYP3A4 and can lower elvitegravir and cobicistat exposure, risking virologic failure and resistance.
What this interaction means in plain words
Efavirenz and Elvitegravir / cobicistat / emtricitabine / tenofovir df are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
Efavirenz induction of CYP3A4 lowers elvitegravir and cobicistat concentrations, plus duplicate antiretroviral therapy.
What to do
Do not use together; select a single complete regimen. Do not add efavirenz to this product.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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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
Frequently asked questions
Can I take Efavirenz with Elvitegravir / cobicistat / emtricitabine / tenofovir df?
MediHelp rates the interaction as contraindicated. Efavirenz and Elvitegravir / cobicistat / emtricitabine / tenofovir df are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. This single-tablet regimen is a complete HIV treatment and is not intended to be combined with other antiretrovirals. Efavirenz induces CYP3A4 and can lower elvitegravir and cobicistat exposure, risking virologic failure and resistance.
How serious is the interaction between Efavirenz and Elvitegravir / cobicistat / emtricitabine / tenofovir df?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not use together; select a single complete regimen. Do not add efavirenz to this product.
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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