What is the treatment approach for rodenticide poisoning?

Treatment Approach for Rodenticide Poisoning

The treatment of rodenticide poisoning requires immediate assessment of coagulation status, with vitamin K1 as the primary antidote for long-acting anticoagulant rodenticide poisoning, which should be administered for extended periods (typically 4-6 weeks) to prevent rebound coagulopathy. 1

Initial Assessment and Management

Immediate Actions

• Contact poison control center immediately (1-800-222-1222 in US) 2
• Provide specific information including:
  • Nature and time of exposure
  • Name of rodenticide product
  • Approximate amount ingested
  • Current symptoms
  • Patient age and weight 2

Clinical Assessment

• Assess for signs of bleeding:
  • Mucocutaneous bleeding (most common)
  • Hematuria
  • Subconjunctival hemorrhage
  • Bruising
  • Intracranial hemorrhage (most common cause of death) 3
• Check vital signs for hemodynamic stability 2
• Evaluate for signs of shock or respiratory distress 4

Laboratory Evaluation

Essential Tests

• Prothrombin time (PT)/INR
• Partial thromboplastin time (PTT)
• Complete blood count
• Renal function tests 3

Timing of Testing

• For asymptomatic patients with ingestion of ≥1 mg of active ingredient: test at 48-72 hours post-exposure 1
• For patients on therapeutic anticoagulants: baseline PT and repeat at 48-72 hours 1

Treatment Protocol

Anticoagulant Rodenticide Poisoning (Warfarin, Brodifacoum, etc.)

Vitamin K1 Administration

• Acute hemorrhagic symptoms: IV vitamin K1 often requiring 50-100 mg initially 3
• Maintenance therapy: 100 mg oral vitamin K1 daily (most common effective dose) 3
• Duration of treatment: Average 168 days; minimum 30 days 3, 5

Blood Component Therapy (for active bleeding)

• Fresh frozen plasma or prothrombin complex concentrate
• Consider recombinant Factor VIIa for severe bleeding 3

Monitoring

• Regular PT/INR monitoring until stable
• Continue monitoring weekly after discontinuation of vitamin K1 to detect rebound coagulopathy 3

Non-Anticoagulant Rodenticide Poisoning

For other types of rodenticides (e.g., bromethalin, cholecalciferol, strychnine):

• Treatment is supportive and specific to the toxin
• Consult poison control for specific management guidelines 4

Special Considerations

Triage Recommendations

1. Immediate ED referral required:

   • Intentional ingestion (self-harm)
   • Symptomatic patients (bleeding, bruising)
   • Chronic ingestion
   • Patients on therapeutic anticoagulants 1

2. Home observation appropriate:

   • Unintentional ingestion of <1 mg active ingredient
   • Asymptomatic patients 1

Pregnant Patients

• Unintentional exposure to <1 mg active ingredient: outpatient evaluation by OB/GYN or primary care 1

Decontamination

• Gastric lavage and ipecac syrup are NOT recommended 1
• Activated charcoal should not delay transportation to ED 1
• For dermal exposures: wash skin with mild soap and water 1

Common Pitfalls and Caveats

• Rebound coagulopathy: Can occur weeks to months after initial treatment due to extremely high affinity of long-acting anticoagulants for vitamin K epoxide reductase 3
• Underestimation of treatment duration: Insufficient duration of vitamin K1 therapy is common; treatment courses average 168 days 3
• Paradoxical thrombosis: Has been reported with LAAR poisoning and hemostatic therapy 3
• Delayed presentation: Coagulopathy may not manifest for 24-48 hours after ingestion 1
• Ocular manifestations: Rodenticide toxicity can present with predominantly ocular signs (subconjunctival hemorrhage, exophthalmos, orbital pain) 5

Prevention Strategies

• Store rodenticides in locked cabinets out of children's reach
• Place baits in areas inaccessible to children
• Consider alternative pest control methods in households with young children 6

By following this structured approach to rodenticide poisoning management, clinicians can effectively reduce morbidity and mortality associated with these exposures while avoiding common treatment pitfalls.