Phytonadione / Vitamin K

Liverpool Hospital Emergency Department


  • Reverse drug induced Vit K deficiency 
  • Warfarin OD intentional
  • Therapeutic Over- Warfarinisation 
  • “Superwarfarin” Anticoagulant Rodenticide Overdose 


  • 10ml/1ml -> Konakion – Given IV
  • 10mg Capsule – PO 
  • 2mg/0.2ml ampule – Konakion Paediatric  

Dosage and Administration 

  • Active life-threatening uncontrollable haemorrhage:
    • 5-10mg IV bolus
  • Warfarin Overdose (ingestion of <0.5mg/kg usually benign in those not on warfarin)
    • Not on regular warfarin: 
    • Measure baseline INR prior to vitamin K. 
    • 10-20mg (paediatric 0.25mg/kg up to 20mg) po or IV. (delay po vit k for 4 hours if  AC given)
    • Repeat INR every 24 hours. 
    • Further 10-20mg if INR >1.4. Generally, no further treatment required after 3 days. 
    • No further INR testing is needed once INR<1.4 on 2 consecutive days 
  • Therapeutic warfarin use: Caution with over correction due to risk of clotting.  
    • Follow eTG management of bleeding and over anticoagulation.
    • Monitor INR every 6 hours
    • Give Vitamin K if INR>5 0.5-2mg IV
    • Repeat doses if remains or returns to >5
    • Start heparin if INR falls <2 and absolute indication for anticoagulation e.g. heparin
  • Paediatric Overdose: 
    • <0.5mg/kg no treatment needed.
    • 0.5-1mg/kg 1 dose 10mg vit K po with no investigations
    • >1mg/kg 10mg Vit K po for 3 days
  • Superwarfarin Overdose
    • Large doses may be required
    • Duration of therapy might be protracted
    • Do not give Vitamin K until anticoagulation has occurred
    • INR >2 use 20-100mg orally or IV BD
    • *INR >10 the higher end of dose range should be used
    • Measure INR daily until <2
    • Monitor weekly after discharge unless INR >2
    • Continue Vitamin K for at least 1 month  

Side Effects 

  • Anaphylaxis – Increased risk if given IV
  • Facial flushing, sweating
  • Venous irritation /phlebitis  

Pit Falls 

  • Safe in pregnancy 
  • Takes 6hrs to work – so not an immediate intervention 
  • Contraindicated if known hyper-sensitivity 
  • Certain patients may be suitable for outpatient INR monitoring 
  • Those that are unlikely to be compliant / concerns regarding DSP / at risk of complications require  inpatient management
  • FFP and Prothrombin X if actively bleeding