Vitamin K

Disambiguation: See ketamine for street name "vitamin K"


  • Lasts up to 2 weeks, possibly making anticoagulation post-bleeding risk difficult
  • IV form has small risk of anaphylaxis, but risks/benefits must be weighed in serious bleeding
  • Type: Vitamin
  • Dosage Forms: 100 mcg; 5mg; SC; IM; IV; PO
  • Common Trade Names: Generic and Mephyton, K1-1000, Novaplus Vitamin K1

Adult Dosing

Vitamin K deficiency hypoprothrombinemia

  • 2.5-25mg PO QD PRN
  • Max: 25mg/dose

Anticoagulant-induced hypoprothrombinemia

  • 10mg PO x1
  • Max: 25mg/dose

Warfarin stabilization

  • 100 mcg PO QD-bid

Pediatric Dosing

Neonatal deficiency (hemorrhagic disease of the newborn)

  • 1mg SC for avoidance of anaphylaxis (IV), hematoma (IM). FFP for serious cases.

Vitamin K deficiency hypoprothrombinemia

  • 2.5-5mg PO QD PRN

anticoagulant induced hypoprothrombinemia

  • 0.5-5mg PO/SC/IM/IV x 1

Special Populations

  • Pregnancy Rating: C
  • Lactation risk: Safe
  • Renal Dosing
    • Adult: not defined
    • Pediatric: not defined
  • Hepatic Dosing
    • Adult: adjust dose amount
    • Pediatric: adjust dose amount


  • Allergy to class/drug
  • hereditary hypoprothrombinemia
  • overanticoagulation due to heparins
  • caution in neonates

Adverse Reactions


  • anticoagulant resistance
  • hypersensitivity reaction, severe or life-threatening (SC, IM, or IV use)
  • anaphylaxis (SC, IM, or IV use)
  • hyperbilirubinemia (neonates)
  • hemolytic anemia (neonates)


  • taste changes (SC, IM, or IV use)
  • flushing (SC, IM, or IV use)
  • injection site hematoma
  • injection site pain


  • Half-life: unknown
  • Metabolism: liver, CYP450: unknown
  • Excretion: urine, bile
  • Mechanism of Action: Used by liver for synthesis of some coagulation factors (II,VII,IX,X,C,S). Timing in the synthesis of these factors impacts reversal of elevated INR (~4 hours: F-VII, ~24 hours: F-II).


See Also