Warfarin

DEA Class; Rx

Common Brand Names; Coumadin, Jantoven

Pregnancy, except in women with mechanical heart valves

Hemorrhagic tendencies or blood dyscrasias

Recent or contemplated CNS or eye surgery or traumatic surgery resulting in large open surfaces

Bleeding tendencies associated with CNS hemorrhage, cerebral aneurysms, dissecting aorta, pericarditis and pericardial effusions, bacterial endocarditis, and active ulceration or overt bleeding of the GI, GU, or respiratory tract

Threatened abortion, eclampsia, and preeclampsia

Unsupervised patients with conditions associated with potential high level of noncompliance (eg, dementia, alcoholism, psychosis)

Spinal puncture and other diagnostic or therapeutic procedures with potential for uncontrollable bleeding

Major regional or lumbar block anesthesia

Known hypersensitivity

Malignant hypertension

Lower doses may be warranted in the elderly, debilitated patients, malnutrition, CHF, or liver disease

Elicits no direct effect on an established thrombus, nor does it reverse ischemic tissue damage

INR >4.0 appears to provide no additional therapeutic benefit in most patients and is associated with a higher risk of bleeding

Skin necrosis reported with use; caution in patients at risk for hemorrhage, necrosis, or gangrene

Heparin-induced thrombocytopenia, DVT (may defer warfarin until thrombin generation is controlled and thrombocytopenia has resolved)

Genetic tests may be warranted to determine best dose for individual patients; variations in CYP2C9 and VKORC1 genes may modify response

Advise patients receiving warfarin to carry a notice stating that they are undergoing anticoagulant therapy, to alert medical/emergency personnel

Use caution in patients with acute infection or active TB or conditions that may alter normal GI flora; antibiotics and fever may change response to warfarin

May release atheromatous plaque emboli; may experience symptoms depending on site of embolization common organs like pancreas, liver, kidneys, and spleen, which may lead to necrosis or death

Use caution in patients with prolonged vitamin K insufficiencies

Thyroid disease may increase warfarin responsiveness

May impair synthesis of coagulation factors in patients with reduced liver function, regardless of etiology, which in turn may lead to increased warfarin sensitivity

Use caution in lactation

Calciphylaxis or calcium uremic arteriolopathy has been reported in patients with and without end-stage renal disease; discontinue warfarin and treat calciphylaxis as appropriate; consider alternative anticoagulant therapy

Maintain consistent intake of vitamin K-containing foods; high vitamin K consumption may decrease warfarin effect

Adverse outcomes in pregnancy occur regardless of the health of the mother or the use of medications; estimated background risk of major birth defects and miscarriage for indicated population is unknown

Not excreted in breast milk as reported in limited published study (AAP Committee states compatible with nursing); because of potential for serious adverse reactions, including bleeding in breastfed infant, consider developmental and health benefits of breastfeeding along with mother’s clinical need for therapy; monitor breastfeeding infants for bruising or bleeding