Warfarin Sodium

Question 1

Trade name

Answer 1

Coumadin®
Jantoven®.

Question 2

Generic name

Answer 2

Warfarin sodium

Question 3

Class of drug

Answer 3

Pharmacologic class: Coumarin derivative
Therapeutic class: Anticoagulant

Question 4

Usual dosage

Answer 4

2 to 5 mg po once daily, with or without food

Question 5

How administered

Answer 5

Be aware that warfarin is a high-alert drug.
• Know that I.V. form is reserved for patients who can’t tolerate oral form.
I.V. and oral dosages are identical.
• For I.V. use, reconstitute vial with 2.7 ml of sterile water for injection; administer over 1 to 2 minutes. After reconstitution, drug is stable for 4 hours at room temperature.
• Be aware that vitamin K reverses warfarin effects. If major bleeding occurs, fresh frozen plasma may be given.
• When converting to warfarin from heparin, give both drugs concomi-tantly for 4 to 5 days until therapeutic effect of warfarin occurs.

Question 6

What is it used for

Answer 6

Venous thrombosis; pulmonary embolism; atrial fibrillation; myocardial infarction (MI); thromboembolic complications of cardiac valve placement

Question 7

Complications/Precautions

Answer 7

Hypersensitivity to drug
• Uncontrolled bleeding
• Open wounds
• Severe hepatic disease
• Hemorrhagic or bleeding tendency
• Cerebrovascular hemorrhage
• Cerebral aneurysm or dissecting aorta
• Blood dyscrasias
• Pericarditis or pericardial effusion
• Bacterial endocarditis
• Malignant hypertension
• Recent brain, eye, or spinal cord injury or surgery
• Lumbar puncture and other procedures that may cause uncontrollable bleeding
• Major regional or lumbar block anesthesia
• Threatened abortion, eclampsia, preeclampsia
• Unsupervised senile, alcoholic, or psychotic patients
• Pregnancy, females of childbearing potential

Precautions
Use cautiously in:
• cancer, heparin-induced thrombocy-topenia, moderate to severe renal impairment, moderate to severe hyper-tension, infectious GI disease, known or suspected deficiency in protein C-mediated anticoagulant response, polycythemia vera, vasculitis, severe diabetes mellitus
• indwelling catheter use
• history of poor compliance
• elderly or debilitated patients
• breastfeeding patients
• children younger than age 18 (safety and efficacy not established).

Bleeding, bruising, pts with liver impairment may require a lower dose

Question 8

Adverse effects

Answer 8

Adverse reactions
GI: nausea, vomiting, diarrhea, abdominal cramps, stomatitis, anorexia
GU: hematuria
Hematologic: eosinophilia, bleeding, hemorrhage, agranulocytosis, leukopenia
Hepatic: hepatitis
Skin: rash, dermatitis, urticaria, pruri-tus, alopecia, dermal necrosis
Other: fever, “purple toes” syndrome (bilateral painful, purple lesions on toes and sides of feet), hypersensitivity reaction

Question 9

Nursing Cosiderations

Answer 9

Patient monitoring
• Monitor PT, INR, and liver function tests.
• Watch for signs and symptoms of bleeding and hepatitis.

Nursing consideration: Adjust dose to maintain INR to 2 to 3.5, dependent on indication