Observation and patient disposition after superwarfarin poisoning

Admit all patients for at least 48 hours of INR monitoring with:

• deliberate superwarfarin poisoning
• ingestion of more than 1 mg of superwarfarin
• a raised international normalised ratio (INR)
• any bleeding complications.

Patients treated with phytomenadione (vitamin K₁) can be discharged with follow up once the INR has stabilised at less than 2. Patients not treated with phytomenadione (vitamin K₁) (because their INR remained normal on serial testing) can be discharged if they remain asymptomatic for at least 48 hours after a deliberate ingestion.

Children with a single accidental ingestion of a superwarfarin, or an adult who unintentionally ingested less than 1 mg of a superwarfarin, do not require investigations and can be discharged. Advise patients to return if they have any abnormal bleeding.