nirmatrelvir/ritonavir vs rifampin
Side-by-side comparison of nirmatrelvir/ritonavir and rifampin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
major Known Drug Interaction
Antimycobacterial rifampin, rifapentine ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance.
Recommendation: Do not take these two medications together.
Paxlovid
Rifadin
Paxlovid is a medicine used to treat mild to moderate COVID-19 in adults. It helps prevent severe illness, hospitalization, or death in people at high risk.
Rifampin is an antibiotic medicine. It fights bacteria in your body to treat infections.
Paxlovid treats mild to moderate COVID-19 in adults. You must be at high risk of your illness becoming severe. This includes needing to go to the hospital or possibly dying from COVID-19. Paxlovid is not for preventing COVID-19 before or after exposure.
Rifampin treats tuberculosis (TB) and helps eliminate the bacteria that cause meningitis from your nose and throat. It is important to use rifampin only for infections that are proven or strongly suspected to be caused by bacteria. This helps to prevent bacteria from becoming resistant to the medicine.
Paxlovid contains two medicines, nirmatrelvir and ritonavir. Nirmatrelvir stops the virus from multiplying in your body. Ritonavir helps nirmatrelvir stay in your body longer so it can work better.
Rifampin works by stopping bacteria from growing and multiplying. It does this by blocking a key enzyme that the bacteria need to make proteins. This helps your body fight off the infection.
- • Change in taste
- • Diarrhea
- • Heartburn
- • Upset stomach
- • Loss of appetite
- • Nausea
- • Vomiting
- COVID-19 22,774
- COVID-19 coming back 20,089
- Change in taste 7,316
- Diarrhea 4,003
- Feeling sick to your stomach 2,620
- Drug Interaction 970
- Drug Reaction With Eosinophilia And Systemic Symptoms 727
- Nausea 628
- Condition Aggravated 550
- Pyrexia 541
Paxlovid can interact with many other medicines, causing serious or life-threatening problems. Before taking Paxlovid, tell your doctor about all the medicines you take. Your doctor may need to adjust the dose of your other medicines or monitor you more closely.
Rifampin can cause liver problems. Tell your doctor right away if you have yellowing of the skin or eyes, dark urine, or stomach pain. Rifampin can also cause blood problems. Tell your doctor if you have unusual bleeding or bruising.
There is not enough information about nirmatrelvir's safety during pregnancy. Studies on ritonavir in pregnant women have not shown an increased risk of birth defects. Talk to your doctor about the risks and benefits of taking Paxlovid if you are pregnant or breastfeeding.
Tell your doctor if you are pregnant or plan to become pregnant. Rifampin can make birth control pills less effective, so use other forms of birth control. Talk to your doctor if you are breastfeeding.
How to Read This nirmatrelvir/ritonavir vs rifampin Comparison
nirmatrelvir/ritonavir is classified in the Antiviral (Protease Inhibitor Combination) drug class, while rifampin sits within the Rifamycin Antibiotic class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, nirmatrelvir/ritonavir has 56,802 submissions while rifampin has 3,416. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known major interaction flagged in FDA labeling, attributed to 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.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between nirmatrelvir/ritonavir and rifampin - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.