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Vitamin K1 (phytomenadione)


  • 10mg/1ml ampoule
  • 10mg tablet

Note: Not interchangeable with vitamin K3


Reversal of coagulopathy caused by warfarin and long-acting anticoagulant rodenticides or superwarfarins.

Konakion (vitamin K1)


Active bleeding due to warfarin poisoning

  • 10mg IV stat

Management of warfarin poisoning in asymptomatic patient

  • 1-5mg IV/PO q6h guided by INR

Management of superwarfarin poisoning

  • 50-100mg IV/PO stat then 50-200mg/day PO in divided doses aiming for an INR < 2. It is advised that these cases are discussed with a clinical toxicologist.

Stocking recommendations

Tertiary centre Regional centre Rural centre Remote centre

20 ampoules / 100 tablets

20 ampoules / 100 tablets 5 ampoules 0 ampoules


Vitamin K1 is readily available in most hospitals. The oral tablet preparation can be difficult to obtain; the IV formulation can be given orally if necessary.


Fact sheet developed by Queensland Poisons Information Centre, Updated: July 2020.

This fact sheet is about the use of these antidotes in Australia, and may not apply to other countries. Children’s Health Queensland Hospital and Health Service cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this fact sheet.