Anticoagulant Poisoning
Description Diagnostic criteria General and supportive measures Medicine treatment ICD-10 code: T45.5 *Notifiable condition (if poisoning due to agricultural or stock remedy, e.g. rodenticide). DESCRIPTION Poisoning due to warfarin and ‘super-warfarins’ (long-acting warfarin) (products such as pellets, granules, wedges, blocks and powder marketed as rodent pesticides). These may be accident
Description
Diagnostic criteria
General and supportive measures
Medicine treatment
ICD-10 code: T45.5
*Notifiable condition (if poisoning due to agricultural or stock remedy, e.g. rodenticide).
DESCRIPTION
Poisoning due to warfarin and ‘super-warfarins’ (long-acting warfarin) (products such as pellets, granules, wedges, blocks and powder marketed as rodent pesticides). These may be accidentally ingested by toddlers or young children.
Note:
Where the history is of an unspecified rat poison or pesticide ingestion, consider other active ingredients such as amitraz and organophosphates.
DIAGNOSTIC CRITERIA
Clinical
- Signs and symptoms depend on the potency, and onset of coagulopathy may be delayed by 48–72 hours. May be asymptomatic if a small quantity has been ingested.
- Bruising or bleeding.
Investigations
- Measure prothrombin time.
- Obtain baseline INR if symptoms/signs present.
- A baseline or repeat INR should be done in all cases of significant ingestion at 36–72 hours post-ingestion.
GENERAL AND SUPPORTIVE MEASURES
- Observe asymptomatic child: may be as outpatient depending on history (amount ingested) and ability to return if symptoms develop.
MEDICINE TREATMENT
ONLY if INR deranged (> 2.5 IU):
Vitamin K1, IV/oral, 1–5 mg/dose administered slowly.
Note:
Intravenous solution can be used orally.
Oral vitamin K1 is usually preferred to intravenous vitamin K1 unless more rapid reversal is required (e.g. the patient is bleeding). Intravenous vitamin K1 may cause hypersensitivity reactions.
If significant bleeding present:
ADD
- Lyophilised plasma IV, 20 mL/kg.
OR
- Fresh frozen plasma, IV, 20 mL/kg.
Repeat vitamin K1 dosing and length of therapy is dependent on INR response to treatment and clinical response—contact poison center for patient specific advice. Ingestion of ‘super-warfarins’ may be refractory to large doses of vitamin K1 and therapy may be required for several weeks after ingestion.
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Paediatrics, 2023 Edition
Chapter 18: Poisoning, 18.1 Poisoning, 18.1.2 Anticoagulant Poisoning