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Coumadin Side Effects

Generic name: warfarin

Medically reviewed by Drugs.com. Last updated on Mar 24, 2023.

Note: This document contains side effect information about warfarin. Some dosage forms listed on this page may not apply to the brand name Coumadin.

Applies to warfarin: oral tablet. Other dosage forms:

Warning

Oral route (Tablet)

Warfarin can cause major or fatal bleeding. Regular monitoring of INR should be performed on all treated patients. Drugs, dietary changes, and other factors affect INR levels achieved with warfarin sodium therapy. Instruct patients about prevention measures to minimize risk of bleeding and to report signs and symptoms of bleeding.

Serious side effects of Coumadin

Along with its needed effects, warfarin (the active ingredient contained in Coumadin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking warfarin:

Less common

Rare

Other side effects of Coumadin

Some side effects of warfarin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Rare

For Healthcare Professionals

Applies to warfarin: compounding powder, intravenous powder for injection, oral tablet.

General

The most common adverse reactions were fatal and nonfatal hemorrhage from any tissue or organ.[Ref]

Cardiovascular

Frequency not reported: Hemorrhage, purple toes syndrome, infarction, systemic cholesterol microembolization, vasculitis, systemic atheroemboli[Ref]

Nervous system

Frequency not reported: Cerebral hemorrhage, cerebral subdural hematoma, lethargy, headache, dizziness, taste perversion, paresthesia[Ref]

Gastrointestinal

Frequency not reported: Gastrointestinal hemorrhage, rectal hemorrhage, hematemesis, pancreatitis, diarrhea, nausea, vomiting, melena, abdominal pain, cramping, flatulence, bloating[Ref]

Dermatologic

Frequency not reported: Rash, alopecia, purpura, erythematous swollen skin patches, ecchymosis, skin necrosis, dermatitis, bullous eruptions, urticaria, pruritus[Ref]

Musculoskeletal

Frequency not reported: Tissue necrosis, chills[Ref]

Metabolic

Frequency not reported: Calciphylaxis, edema[Ref]

Respiratory

Frequency not reported: Hemothorax, epistaxis, tracheal or tracheobronchial calcification[Ref]

Genitourinary

Frequency not reported: Hematuria[Ref]

Hematologic

Frequency not reported: Unexplained decrease in hematocrit, hemoglobin decreased[Ref]

Hepatic

Frequency not reported: Jaundice, hepatic dysfunction, hepatitis, cholestatic hepatic injury, liver enzymes elevated[Ref]

Immunologic

Frequency not reported: Hypersensitivity, allergic reactions, anaphylactic reactions[Ref]

Other

Frequency not reported: Fever, fatigue, malaise, asthenia, pain, cold intolerance, feeling cold[Ref]

Frequently asked questions

References

1. Product Information. Coumadin (warfarin). DuPont Pharmaceuticals. 2001.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.