Warfarin and Rodenticides

Question 1

Discuss single accidental ingestion of rodenticides.

Answer 1

Does not cause significant anticoagulation.

Question 2

Discuss the toxic mechanism of superwarfarins.

Answer 2

Inhibit vitamin-K dependent production of clotting factors II, VII, IX and X. They have greater potency than warfarin due to greater affinity for vitamin K-2,3-epoxide reductase, hepatic accumulation and disruption of vitamin K cycle.

Question 3

If there is uncontrolled haemorrhage with superwarfarins what should your management be?

Answer 3

FFP (10-15 ml/kg), prothrombinex (25-50 IU/kg) and vitamin K 10 mg IV

Question 4

When is activated charcoal indicated with superwarfarin poisoning.

Answer 4

Not after accidental ingestions, following massive single acute self-poisoning it is within 12 hours

Question 5

What is an important pitfall when it comes to superwarfarin poisoning?

Answer 5

Empiric vitamin K therapy following an acute ingestion - this will mask subsequent toxicity, delays diagnosis and prolongs the need for ongoing follow-up