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Coumadin (Warfarin Sodium) - Side Effects and Adverse Reactions



Potential adverse reactions to COUMADIN may include:

  • Fatal or nonfatal hemorrhage from any tissue or organ. This is a consequence of the anticoagulant effect. The signs, symptoms, and severity will vary according to the location and degree or extent of the bleeding. Hemorrhagic complications may present as paralysis; paresthesia; headache, chest, abdomen, joint, muscle or other pain; dizziness; shortness of breath, difficult breathing or swallowing; unexplained swelling; weakness; hypotension; or unexplained shock. Therefore, the possibility of hemorrhage should be considered in evaluating the condition of any anticoagulated patient with complaints which do not indicate an obvious diagnosis. Bleeding during anticoagulant therapy does not always correlate with PT/INR. (See OVERDOSAGE: Treatment.)
  • Bleeding which occurs when the PT/INR is within the therapeutic range warrants diagnostic investigation since it may unmask a previously unsuspected lesion, e.g., tumor, ulcer, etc.
  • Necrosis of skin and other tissues. (See WARNINGS.)
  • Adverse reactions reported infrequently include: hypersensitivity/allergic reactions, including anaphylactic reactions, systemic cholesterol microembolization, purple toes syndrome, hepatitis, cholestatic hepatic injury, jaundice, elevated liver enzymes, hypotension, vasculitis, edema, anemia, pallor, fever, rash, dermatitis, including bullous eruptions, urticaria, angina syndrome, chest pain, abdominal pain including cramping, flatulence/bloating, fatigue, lethargy, malaise, asthenia, nausea, vomiting, diarrhea, pain, headache, dizziness, loss of consciousness, syncope, coma, taste perversion, pruritus, alopecia, cold intolerance, and paresthesia including feeling cold and chills.

Rare events of tracheal or tracheobronchial calcification have been reported in association with long-term warfarin therapy. The clinical significance of this event is unknown.

Priapism has been associated with anticoagulant administration; however, a causal relationship has not been established.


Below is a sample of reports where side effects / adverse reactions may be related to Coumadin. The information is not vetted and should not be considered as verified clinical evidence.

Possible Coumadin side effects / adverse reactions in 75 year old female

Reported by a consumer/non-health professional from United States on 2011-10-03

Patient: 75 year old female weighing 45.4 kg (99.8 pounds)

Reactions: Nasopharyngitis, Haemorrhage, Pain, Anaemia, Myelodysplastic Syndrome, Fatigue, Skin Discolouration, Alopecia, Depression, Cardiac Failure Congestive

Adverse event resulted in: life threatening event

Suspect drug(s):

Possible Coumadin side effects / adverse reactions in 84 year old male

Reported by a physician from United States on 2011-10-03

Patient: 84 year old male

Reactions: Soft Tissue Disorder, Atelectasis, Seborrhoeic Keratosis, Dyslipidaemia, Throat Cancer, Flatulence, Coagulopathy, Pulmonary Embolism, Oesophagitis Ulcerative, Fall, Hypokalaemia, Oesophageal Stenosis, Skin Cancer, Head and Neck Cancer, Injury, Cough, Hiatus Hernia, Prostate Cancer, Peptic Ulcer, Haemorrhoids, Anaemia, Atrial Fibrillation, Barrett's Oesophagus, Diarrhoea, Dehydration, Peptic Ulcer Haemorrhage, Hypothyroidism, Feeding Tube Complication, Hypertension, Deep Vein Thrombosis

Adverse event resulted in: hospitalization

Suspect drug(s):
    Administration route: Oral
    Start date: 2000-01-01



Other drugs received by patient: Warfarin Sodium; Carafate; Thiamine HCL; Multivitamin with Iron and Fluoride; Levothyroxine; Xanax; Vitamin D with Calcium; Synthroid; Folic Acid; Percocet

Possible Coumadin side effects / adverse reactions in 86 year old male

Reported by a physician from Italy on 2011-10-04

Patient: 86 year old male

Reactions: Muscle Haemorrhage

Adverse event resulted in: life threatening event

Suspect drug(s):
    Indication: Pulmonary Embolism

    Indication: Deep Vein Thrombosis

    Dosage: 1 gm;qd;im
    Indication: Product Used FOR Unknown Indication
    Start date: 2011-04-23
    End date: 2011-05-01

See index of all Coumadin side effect reports >>

Drug label data at the top of this Page last updated: 2007-11-14

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