II. Background
III. Physiology
- Vitamin K is required for Coagulation Factors 2,7, 9, 10 and Protein C and Protein S
- Vitamin K Deficiency may result in Bleeding Disorders
- Vitamin K Toxicity or Overdose may result in Hemolytic Anemia or Kernicterus
-
Warfarin (Coumadin) is a Vitamin K mimic that functions as a Competitive Antagonist to Vitamin K epoxide reductase
- Results in Vitamin K Deficiency
IV. Indication
- Reversal of excessive Anticoagulation with Coumadin
V. Dosing (See Coumadin Protocol)
- Routes: IV, IM, SQ, PO
- Oral route is preferred in most cases (consistently absorbed with excellent efficacy)
- IV route is indicated in life threatening bleeding or intolerance to oral administration
- IV route risks anaphylactic reaction (esp. rapid infusion)
- Intramuscular Injection (of any medication) is not recommended with supratherapeutic INR
- Risk of Muscle and Extremity Injury due to localized bleeding
- Subcutaneous administration is not recommended due to unpredictable absorption
- INR 4 to 10
- Give Vitamin K 1-2 mg orally
- Dilute Parenteral Vitamin K 1-2 mg in flavored drink
- Administer Vitamin K 0.5-1 mg IV if not able orally
- INR over 10 without bleeding complications
- Vitamin K 3 mg SC or slow IV infusion (over 15-30 min)
- Check INR at 6 hours
- Consider repeating Vitamin K at 6 hours if unchanged
- Serious bleeding complication at any elevated INR
- Replace Clotting Factors
- Vitamin K 10 mg SC or slow IV infusion
- Fresh Frozen Plasma (FFP) 15 ml/kg
- Prothrombin Complex Concentrate (PCC) 50 U/kg
- Check INR at 6 hours
- Replace Clotting Factors
VI. Precautions
-
Anticoagulant-laced Synthetic Cannabinoids
- Drugs contaminated with Brodifacoum rat poison
- May require Vitamin K doses as high as 50 mg orally tid for months
- Extortionary Vitamin K prices of $50 per 5 mg Vitamin K tab, may cost $45,000 per month
- (2018) Presc Lett 25(6):35 [PubMed]
VII. Research: Guideline Studies (See Coumadin Protocol)
- Consensus Conference (Dalen) advocates giving
- Vitamin K SC/IV for INR > 6
- Dalen (1995) Chest 108 (sppl):225S-522S (Consensus) [PubMed]
- Retrospective study of 51 Arizona Patients with INR >6
- No Vitamin K given in 48 patients, Coumadin stopped
- No adverse outcomes or major bleeding
- Glover (1995) Chest 108:987-90 [PubMed]
- Oral Vitamin K 1 mg acts faster than subcutaneous
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