Efavirenz and Famotidine Interaction
Drug interaction information between Efavirenz and Famotidine.
Efavirenz and Famotidine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Efavirenz and Famotidine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
These two medicines do not have a meaningful effect on each other when taken at the same time.
FDA Label Information
7.5 Drugs Without Clinically Significant Interactions with Efavirenz No dosage adjustment is recommended when efavirenz is given with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, lorazepam, nelfinavir, nucleoside reverse transcriptase inhibitors (abacavir, emtricitabine, lamivudine, stavudine, tenofovir disoproxil fumarate, zidovudine), paroxetine, and raltegravir.
Efavirenz Also Interacts With
- Clarithromycin moderate
- Sofosbuvir/Velpatasvir moderate
- Posaconazole moderate
- Atorvastatin minor
- Sertraline minor
Famotidine Also Interacts With
- Theophylline major
- Tizanidine moderate
- Ketoconazole minor
- Ledipasvir/Sofosbuvir minor
- Itraconazole minor
Frequently Asked Questions
What SPL severity band is on file for Efavirenz/Emtricitabine/Tenofovir + Famotidine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Efavirenz has 32 labeled pairs on file vs Famotidine's 11. In the minor band specifically: Efavirenz has 29 (also Atorvastatin, Sertraline, Bupropion, Simvastatin); Famotidine has 9 (also Ketoconazole, Ledipasvir/Sofosbuvir, Itraconazole, Aripiprazole).
What mechanism field is on file for Efavirenz/Emtricitabine/Tenofovir and Famotidine?
These two medicines do not have a meaningful effect on each other when taken at the same time.
Famotidine carries more major-labeled pairs than Efavirenz
SPL source-record counts only. This page's band is minor · classes on file: Efavirenz (NNRTI / NRTI Combination); Famotidine (H2 Receptor Antagonist).
Famotidine has 1 major-labeled pair vs Efavirenz's 0. This page itself is in the minor band, not the major band.
0 major · 3 moderate · 29 minor · 32 total
- Other minor peers for Efavirenz
- Atorvastatin
- Sertraline
- Bupropion
- Simvastatin
1 major · 1 moderate · 9 minor · 11 total
- Other minor peers for Famotidine
- Ketoconazole
- Ledipasvir/Sofosbuvir
- Itraconazole
- Aripiprazole
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.