Based on NIH | Is nausea a side effect of warfarin, and how common is it?

Yes nausea is a recognized adverse effect of warfarin. ^{[1] [2]} It is listed among gastrointestinal side effects in official product information along with vomiting, diarrhea, abdominal pain, flatulence, bloating, and taste changes (taste perversion). ^{[1] [3]} While exact frequencies are not routinely quantified in the warfarin label, available clinical trial summaries suggest nausea occurs in a small minority of users. ^{[1] [4]}

What the official information says

• Warfarin’s prescribing information includes “nausea” under gastrointestinal disorders. ^[1] These listings consistently appear across multiple official label versions for warfarin tablets. ^[3]
• The same sections list related GI symptoms vomiting, diarrhea, abdominal pain, flatulence, bloating, and taste perversion indicating that dyspeptic complaints can occur during therapy. ^{[1] [5]}

How common nausea is

• The FDA‑approved warfarin labeling catalogs nausea but does not assign a specific percentage frequency. ^[1] In general, labels group these events as postmarketing or clinical trial adverse reactions without firm incidence estimates. ^[1]
• Comparative trial data summarized in a systematic review found one randomized study that directly reported nausea rates of about 1.5% with vitamin K antagonists (the class that includes warfarin) versus 2.7% with a direct thrombin inhibitor. ^[4] This suggests nausea with warfarin‑class therapy occurs in a small proportion of participants, likely in the low single digits. ^[4]

Context vs. other blood thinners

• Across trials in atrial fibrillation, gastrointestinal complaints are common overall, but newer agents (especially some direct thrombin inhibitors) tended to show higher rates of GI symptoms or discontinuations than vitamin K antagonists like warfarin. ^[4] This pattern supports that warfarin can cause nausea, though it may not be the most frequent culprit among anticoagulants. ^[4]

Practical tips if you feel nauseated

• Taking warfarin with food may reduce stomach upset for some people, while still maintaining consistent timing daily. (General guidance no label citation required)
• Check for other triggers: new medications, alcohol, or supplements can interact with warfarin and worsen GI symptoms or INR stability. ^[6] Consistent diet and careful review of over‑the‑counter products are helpful. ^[6]
• If nausea is persistent or severe, discuss it with your clinician; they may check your INR, assess for drug interactions, or consider other causes of GI symptoms. (General clinical advice no label citation required)

---

Quick reference table

Item	What to know
Is nausea a listed side effect of warfarin?	Yes; included under “Gastrointestinal disorders” in official product information. [1] [3]
Other GI effects listed	Vomiting, diarrhea, abdominal pain, flatulence, bloating, taste perversion. [1] [5]
How common?	Label does not specify a percentage; one trial suggests ~1–2% range for VKAs, indicating low single‑digit incidence. [4]
Comparison with some newer anticoagulants	Some newer agents show higher GI symptom rates or discontinuations in trials compared with vitamin K antagonists. [4]

If you’re experiencing nausea on warfarin, you’re not alone and it can happen, but it’s usually not very common; checking for interactions, keeping dosing consistent with food, and letting your clinician know about persistent symptoms are reasonable next steps. ^{[1] [4]}