oseltamivir vs warfarin
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of oseltamivir and warfarin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
7.2 Drugs Without Clinically Significant Drug Interaction with Oseltamivir Phosphate for Oral Suspension No dose adjustments are needed for either oseltamivir or the concomitant drug when coadministering oseltamivir with amoxicillin, acetaminophen, aspirin, cimetidine, antacids (magnesium and aluminum hydroxides and calcium carbonates), rimantadine, amantadine, or warfarin [see Clinical Pharmacology (12.3) ] .
Tamiflu
Coumadin, Jantoven
Oseltamivir (Tamiflu) is an antiviral medicine. It helps treat and prevent the flu (influenza A and B).
Warfarin is a medicine that helps prevent blood clots. It is used to treat and prevent dangerous clots from forming in your body.
This medicine treats the flu in people 2 weeks and older who have had symptoms for no more than 48 hours. It can also prevent the flu in people 1 year and older. Remember that this medicine is not a substitute for your yearly flu shot. It's important to get vaccinated every year.
Warfarin is used to prevent and treat blood clots in your veins and lungs. It can also prevent clots if you have atrial fibrillation (irregular heartbeat) or a replacement heart valve. After a heart attack, it can lower the risk of death, another heart attack, or a stroke.
Oseltamivir stops the flu virus from spreading in your body. It does this by blocking a protein on the virus called neuraminidase. This helps you get better faster or prevents you from getting sick.
Warfarin works by blocking your body's use of vitamin K. Vitamin K is needed to make blood clotting factors. By blocking vitamin K, warfarin makes your blood less likely to clot.
- • Nausea
- • Vomiting
- • Headache
- • Pain
- • Bleeding from any tissue or organ
- Vomiting 444
- Nausea 443
- Headache 381
- Pneumonia 368
- Condition Aggravated 332
- International Normalised Ratio Increased 10,276
- Dyspnoea 8,408
- Drug Interaction 6,288
- Fatigue 6,143
- Nausea 5,921
Rarely, this medicine has been linked to serious skin reactions and allergic reactions. Stop taking this medicine and get medical help right away if you have signs of an allergic reaction or a severe skin rash. Some people, especially children, may experience confusion or unusual behavior while taking this medicine. Watch for any changes in behavior and tell your doctor right away.
Warfarin can cause major or fatal bleeding. You must have your blood tested regularly (INR) while taking warfarin. Many things, like other medicines and diet changes, can affect your INR. Tell your doctor about any bleeding and follow their instructions to prevent bleeding.
Tell your doctor if you are pregnant or plan to become pregnant. Studies suggest this medicine does not increase the risk of birth defects. Talk to your doctor about the risks and benefits of taking this medicine while pregnant or breastfeeding.
Warfarin can harm your unborn baby, especially during the first three months of pregnancy. Do not take warfarin if you are pregnant, unless you have a mechanical heart valve and your doctor says the benefits outweigh the risks. Talk to your doctor if you are breastfeeding, and watch your baby for bruising or bleeding.
How to Read This oseltamivir vs warfarin Comparison
oseltamivir is classified in the Neuraminidase Inhibitor (Antiviral) drug class, while warfarin sits within the Vitamin K Antagonist (Anticoagulant) 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, oseltamivir has 1,968 submissions while warfarin has 37,036. 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 minor interaction flagged in FDA labeling, attributed to these drugs do not change how the body handles or clears either medicine from your system.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for oseltamivir or warfarin.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.