Vitamin K (Phytomenadione)

Vitamin K is necessary for the production of prothrombin, factors VII, IX and X. It is found primarily in leafy green vegetables and is additionally synthesised by bacteria that colonise the gut. Because it is fatsoluble, it requires bile salts for absorption from the gut. Patients with biliary obstruction or hepatic disease may become deficient.Vitamin K deficiency is not uncommon in hospitalised patients because of poor diet, parenteral nutrition, recent surgery, antibiotic therapy or uraemia.

Uses
Liver disease
Reversal of warfarin

Contraindications
Hypersensitivity
Reversal of warfarin when need for re-warfarinisation likely (use FFP)

Administration
• Konakion® (0.5-ml ampoule containing 1 mg phytomenadione)

IV bolus: 1–10 mg, give over 3–5 min Contains polyethoxylated castor oil which has been associated with anaphylaxis; should not be diluted

• Konakion® MM (1-ml ampoule containing 10 mg phytomenadione in a colloidal formulation)
IV bolus: 1–10 mg, give over 3–5 min
IV infusion: dilute with 55 ml glucose 5%; give over 60 min. Solution should be freshly prepared and protected from light
Not for IM injection

Maximum dose: 40 mg in 24 h

How not to use vitamin K
Do not give by rapid IV bolus
Do not give IM injections in patients with abnormal clotting
Not for the reversal of heparin

Adverse effects
Hypersensitivity

Cautions
Onset of action slow (use FFP if rapid effect needed)