Coumadin (Warfarin) management

Alcohol?

Avoid drinking or limit to no more than 1-2 servings occasionally; increases risk of bleeding even if INR is in target range

Consistently stable INR

Check q 2-4 weeks up to 12 weeks per the ACCP

Adverse reaction

"Purple toes syndrome" (rare); skin necrosis located in subcutaneous fat, breasts, extremities, trunk (within first few days of receiving large doses of warfarin)

Clinical pearls

-After warfarin is discontinued, anticoagulant effects persist for 2-5 days -Be aware of increased bleeding risk with certain drugs -Asian patients may require lower starting and maintenance doses of warfarin -Some genotypes require lower doses of warfarin -Persons > 60 are more likely to have significant increase in INR after increase in dose compared with younger parents -INR values lower than 2.0 increase stroke risk sixfold -Mayonnaise, canola oil, soybean oil also have high levels of vitamin K Warfarin algorithms and dosing calculators/programs are available online

S/Sx: Elevated INR

Educate patient to call if prolonged bleeding from cuts, frequent nosebleeds, bloody/tarry stool, hematuria, petechiae, excessive bruising, excessive menstrual bleeding, persistent oozing/bleeding gums after brushing, sudden decease in hub, new onset of severe headache especially after a fall (CSN bleed)

Single out-of-range INR

If patient has stable INR and has a single out-of-range INR equal to or less than 0.5 below or above therapeutic INR (2-3), experts suggest continuing current warfarin dose; retest INR within 1-2 weeks

INR < 5 with no significant bleeding risk

Omit one dose and/or reduce maintenance dose slightly; recheck INR

One dose missed

Take the dose asap on the same day. Do NOT double dose the next day.

Vitamin K

The ACCP advises against routine vitamin K1 (phytonadione) supplementation Dietary issues: Do not forget to review patient's daily dietary intake of vitamin K foods (kale, spinach, collards/mustard/beet greens, broccoli raab); high intake of vitamin K will reduce anticoagulant effect of warfarin (will decrease INR)