Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir Interaction
Drug interaction information between Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir.
Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
One medicine lowers the amount of the hepatitis C drug in your body, which can stop it from working correctly.
What To Do
This combination is not recommended because it may cause your hepatitis C treatment to fail.
FDA Label Information
Velpatasvir/ Sofosbuvir ↓ velpatasvir Co-administration of efavirenz and sofosbuvir/velpatasvir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir Velpatasvir /Sofosbuvir/Voxilaprevir ↓ velpatasvir ↓ voxilaprevir Co-administration of efavirenz and sofosbuvir/velpatasvir/voxilaprevir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir/voxilaprevir.
Efavirenz/Emtricitabine/Tenofovir Also Interacts With
- Clarithromycin moderate
- Posaconazole moderate
- Atorvastatin minor
- Sertraline minor
- Bupropion minor
Sofosbuvir/Velpatasvir Also Interacts With
- Rifampin major
- Rosuvastatin major
- Rosuvastatin/Ezetimibe major
- Pravastatin moderate
- Methotrexate moderate
Frequently Asked Questions
Can I take Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir together?
This is a moderate interaction. This combination is not recommended because it may cause your hepatitis C treatment to fail.
How serious is the interaction between Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir interact?
One medicine lowers the amount of the hepatitis C drug in your body, which can stop it from working correctly.
Understanding the Efavirenz/Emtricitabine/Tenofovir and Sofosbuvir/Velpatasvir Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Efavirenz/Emtricitabine/Tenofovir belongs to the NNRTI / NRTI Combination class and Sofosbuvir/Velpatasvir belongs to the NS5B/NS5A Inhibitor (HCV) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: One medicine lowers the amount of the hepatitis C drug in your body, which can stop it from working correctly. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Efavirenz/Emtricitabine/Tenofovir has 32 total documented interactions on file in this dataset, and Sofosbuvir/Velpatasvir has 33. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: This combination is not recommended because it may cause your hepatitis C treatment to fail. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Efavirenz/Emtricitabine/Tenofovir or Sofosbuvir/Velpatasvir based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.