Warfarin: uses, dosing, side effects & brands
Warfarin is a medicine sold in the U.S. under 2 brand and generic names. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Available as
- Tablet
- Sold as
- 2 products — Coumadin and Panwarfin
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Half-life
- about 40 hours (the label's effective half-life; range 20 to 60 hours)
- What the pharmacy pays
- about $3 for a 30-count supply — not your price
Can you take warfarin with…?
Source-cited answers for the combinations people actually ask about — each with a verdict and what to watch for.
Every warfarin product we track (2)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 72/100 | Prescription | Tablet | Generic | $3 | View → | |
| 2 | 72/100 | Prescription | Tablet | Generic | $3 | View → |
What warfarin pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
Combination products containing warfarin
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
How long warfarin keeps
No warfarin label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Warfarin and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for warfarin: levels in milk, effects in breastfed infants, and the drugs it would consider insteadBecause of the very low milk levels with warfarin doses up to at least 12 mg daily, amounts ingested by the infant are small. No adverse reactions in breastfed infants have been reported from maternal warfarin use during lactation, even with a dose of 25 mg daily for 7 days. There is a consensus that maternal warfarin therapy during breastfeeding poses little risk to the breastfed infant. No special precautions are necessary.
National Institute of Child Health and Human Development, record revised May 15, 2024. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about warfarin
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 47,132 reports naming warfarin, and the FDA flagged 80% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- international normalised ratio increased5,147 reports
- dyspnoea2,594 reports
- fatigue2,127 reports
- nausea2,122 reports
- diarrhoea1,941 reports
- dizziness1,905 reports
- anaemia1,738 reports
- asthenia1,733 reports
Read these as a signal, not a rate. A report does not mean warfarin caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.
Source: openFDA drug/event (FAERS), retrieved August 26, 2026.
How long warfarin stays in your system
The elimination half-life of warfarin is about 40 hours (the label's effective half-life; range 20 to 60 hours). Half-life varies widely between people (20 to 60 hours), partly due to CYP2C9 genetic differences, and warfarin is a mix of R- and S-warfarin that clear at different rates (R: 37 to 89 hours; S: 21 to 43 hours); the label also notes a terminal half-life of about 1 week after a single dose.
Warfarin Sodium Tablets, USP (DailyMed) ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Related calculators
Frequently asked questions
How long does warfarin stay in your system?
The elimination half-life of warfarin is about 40 hours (the label's effective half-life; range 20 to 60 hours) — that is how long the body takes to clear half of a dose. Half-life varies widely between people (20 to 60 hours), partly due to CYP2C9 genetic differences, and warfarin is a mix of R- and S-warfarin that clear at different rates (R: 37 to 89 hours; S: 21 to 43 hours); the label also notes a terminal half-life of about 1 week after a single dose. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take warfarin with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run warfarin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is warfarin sold under?
We track 2 warfarin-containing products in the U.S.: Coumadin and Panwarfin. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does warfarin come in?
Across the brands we track, warfarin is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic warfarin?
We do not currently list a generic-labelled warfarin product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
What should I avoid while taking warfarin?
Other medicines: we hold source-cited interaction answers for Can you eat leafy greens (vitamin K) while taking warfarin?. This is what the FDA label and our cited sources say — it is not a complete list. Your pharmacist can check your own combination.
Cite this page
- APA
- pharmaranks. (2026, July 24). Warfarin: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/warfarin
- MLA
- “Warfarin: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/warfarin.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for warfarin on DailyMed (NIH) ↗.