Warfarin (Coumadin) Flashcards

Study Notes

Warfarin Overview

Warfarin (Coumadin) is classified as an anticoagulant, used to prevent blood clots.

Contraindications

Not suitable for patients with bleeding disorders, peptic ulcers, recent strokes, severe liver or kidney disease, eclampsia, hemophilia, and alcoholism.
Use caution in patients with diabetes and leukemia.

Mode of Action

Works by inhibiting the hepatic synthesis of vitamin K-dependent clotting factors: II (prothrombin), VII, IX, and X.

Side Effects

Common side effects include anorexia, gastrointestinal disturbances, abdominal cramps, skin reactions, and fever.

Adverse Reactions

Life-threatening reaction includes hemorrhage; other significant reaction is Purple Toe Syndrome.

Drug-Lab-Food Interactions

Drug interactions can enhance effects with amiodarone, NSAIDs, some antibiotics, and vitamin E; reduce effects with barbiturates, certain vitamins, and oral contraceptives.
Lab tests may show increased AST and ALT levels.
Diets high in vitamin K can decrease warfarin's effectiveness.

Route of Administration

Administered orally (PO).

Assessment Considerations

Obtain full health history related to clotting, including liver and renal function.
Monitor potential drug interactions, especially with highly protein-bound medications.
Establish baseline PT or INR before therapy initiation.

Planning Goals

Aim for PT of 1.25 to 2.5 times the control level, or INR between 2-3 while preventing excessive bleeding.

Nursing Interventions

Monitor vital signs; increased pulse with decreased systolic pressure may indicate bleeding.
Regularly check mucous membranes, urine, skin, and stools for signs of bleeding.
Keep anticoagulant antagonists like Vitamin K readily available in emergencies.

Patient Teaching

Encourage informing healthcare providers and dentists when using warfarin.
Advise use of soft toothbrushes and electric razors to minimize bleeding risks.
Warn against smoking due to its effect on drug metabolism.
Caution against OTC medications and herbal supplements that may interact.
Educate on managing external bleeding through direct pressure.

Dietary Considerations

Patients should avoid or be consistent with intake of foods high in vitamin K and limit caffeine and alcohol consumption.
Awareness of dietary supplements that may reduce warfarin efficacy, such as Coenzyme Q10 and garlic.

Evaluation of Therapy

Assess drug therapy effectiveness by monitoring PT or INR levels and ensuring absence of significant side effects.

Clinical Uses

Primarily used to prevent thromboembolic events such as deep vein thrombosis (thrombophlebitis), pulmonary embolism, and strokes related to atrial fibrillation.

Pharmacokinetics

Warfarin has a long half-life and a sustained action, necessitating careful monitoring of effects and dosages.

Antidote for Overdose

Vitamin K is the specific antidote for warfarin overdose but requires careful administration.

Description

Test your knowledge about Warfarin, an anticoagulant drug, with these flashcards. The quiz covers various aspects including its drug class, contraindications, and mode of action. Ideal for students in pharmacology or healthcare fields.