Massive warfarin overdose management in an adolescent patient

Area of Science:

• Toxicology
• Pharmacology
• Emergency Medicine

Background:

• Warfarin is a common oral anticoagulant with established reversal guidelines for supratherapeutic International Normalized Ratios (INRs).
• Limited data exists on managing acute warfarin overdose in individuals without a chronic anticoagulation indication.

Observation:

• A 15-year-old male with no anticoagulation indication ingested 1,000 mg of warfarin.
• INR levels increased from 1.9 at 16 hours post-ingestion to over 11.8 by hospital day 4.
• Oral vitamin K was administered on hospital day 4, with INR normalizing by hospital day 7.

Findings:

• The patient's INR rose significantly despite initial recommendations to withhold vitamin K.
• Delayed vitamin K administration was necessary when INR exceeded 10, aligning with general overdose management principles.
• Extrapolating established warfarin reversal guidelines to acute overdose in non-anticoagulated patients presents uncertainties.

Implications:

• This case highlights the need for careful monitoring and potentially individualized treatment strategies for acute warfarin overdose in non-anticoagulated patients.
• Current warfarin reversal guidelines may require re-evaluation for applicability in overdose scenarios outside of chronic anticoagulation.
• Further research is needed to establish best practices for managing acute warfarin ingestion in patients without a medical indication for anticoagulation.