The oral coumarin anticoagulants, warfarin and phenindione, interfere with Vitamin K metabolism in hepatic cells and their effects can be reversed by vitamin K. If anticoagulation with warfarin is to be continued but rapid reversal of over- anticoagulation is needed a small oral dose of 0.5 to 1mg of vitamin K is generally sufficient. Larger doses lead to prolonged resistance to warfarin.

Intravenous injections of vitamin K should be given with caution as anaphylaxis may occur.

Menadiol sodium phosphate

• Tablets 10mg (£132.56 = 20mg daily)

Indications

• Prevention of vitamin K deficiency in malabsorption syndromes

Phytomenadione (Vitamin K1)

• Solution for injection 10mg in 1ml (£1.05 = 1ml ampoule)
• Solution for injection 2mg in 0.2ml (£2.10 = 0.2ml ampoule)

Notes

1. May be given by a single intramuscular injection at birth - see local hospital policy
2. May be used to reverse over-anticoagulation