Nirmatrelvir/Ritonavir and Rifampin Interaction
Drug interaction information between Nirmatrelvir/Ritonavir and Rifampin.
Nirmatrelvir/Ritonavir and Rifampin have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Nirmatrelvir/Ritonavir and Rifampin. 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
Rifampin causes the body to break down nirmatrelvir/ritonavir too quickly, which lowers the amount of medicine in your blood. This can make the treatment less effective and may lead to the virus becoming resistant.
FDA Label Information
Antimycobacterial rifampin, rifapentine ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance.
Nirmatrelvir/Ritonavir Also Interacts With
- Simvastatin major
- Lovastatin major
- Sildenafil major
- Carbamazepine major
- Lurasidone major
Rifampin Also Interacts With
- Darunavir major
- Bictegravir/Emtricitabine/Tenofovir major
- Glecaprevir/Pibrentasvir major
- Pitavastatin major
- Ranolazine major
Frequently Asked Questions
What SPL severity band is on file for Nirmatrelvir/Ritonavir + Rifampin?
Compiled FDA labeling labels this pair major. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Rifampin has 137 labeled pairs on file vs Nirmatrelvir/Ritonavir's 86. In the major band specifically: Nirmatrelvir/Ritonavir has 23 (also Simvastatin, Lovastatin, Sildenafil, Carbamazepine); Rifampin has 8 (also Darunavir, Bictegravir, Glecaprevir/Pibrentasvir, Pitavastatin).
What mechanism field is on file for Nirmatrelvir/Ritonavir and Rifampin?
Rifampin causes the body to break down nirmatrelvir/ritonavir too quickly, which lowers the amount of medicine in your blood. This can make the treatment less effective and may lead to the virus becoming resistant.
Nirmatrelvir/Ritonavir carries more major-labeled pairs than Rifampin
SPL source-record counts only. This page's band is major · classes on file: Nirmatrelvir/Ritonavir (Antiviral (Protease Inhibitor Combination)); Rifampin (Rifamycin Antibiotic).
Nirmatrelvir/Ritonavir has 23 major-labeled pairs vs Rifampin's 8.
23 major · 30 moderate · 33 minor · 86 total
- Other major peers for Nirmatrelvir/Ritonavir
- Simvastatin
- Lovastatin
- Sildenafil
- Carbamazepine
8 major · 26 moderate · 103 minor · 137 total
- Other major peers for Rifampin
- Darunavir
- Bictegravir
- Glecaprevir/Pibrentasvir
- Pitavastatin
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.