Drug interactions
Efavirenz + Ombitasvir / paritaprevir / ritonavir
Severity: Contraindicated
Efavirenz and Ombitasvir / paritaprevir / ritonavir: 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
Efavirenz may lower paritaprevir and ombitasvir concentrations, reducing hepatitis C antiviral activity. It has also been associated with liver enzyme elevations with this regimen.
What this interaction means in plain words
Efavirenz and Ombitasvir / paritaprevir / ritonavir 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 reduces paritaprevir and related drug exposure.
What to do
Do not coadminister. Use an HCV regimen compatible with efavirenz or switch the antiretroviral.
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 Ombitasvir / paritaprevir / ritonavir?
MediHelp rates the interaction as contraindicated. Efavirenz and Ombitasvir / paritaprevir / ritonavir 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. Efavirenz may lower paritaprevir and ombitasvir concentrations, reducing hepatitis C antiviral activity. It has also been associated with liver enzyme elevations with this regimen.
How serious is the interaction between Efavirenz and Ombitasvir / paritaprevir / ritonavir?
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 coadminister. Use an HCV regimen compatible with efavirenz or switch the antiretroviral.
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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