What is the management of rodenticide (rat killer) poisoning?

Management of Rodenticide Poisoning

Immediately prioritize supportive care—airway management, hemodynamic support, and correction of critical vital signs—before attempting to identify the specific rodenticide type, and contact poison control (1-800-222-1222 in the US) without delay. 1, 2

Immediate Stabilization (First Priority)

The most critical error in rodenticide poisoning is delaying supportive care while awaiting toxin identification. 2, 3 Treatment must begin based on clinical presentation alone.

Initial resuscitation steps:

• Secure airway if patient shows CNS depression, loss of protective reflexes, or respiratory compromise 1
• Establish IV access and correct hemodynamic instability before pursuing antidote therapy 2
• Administer oxygen, and in altered mental status consider naloxone, glucose, and thiamine 4
• Activate EMS immediately if patient exhibits sleepiness, seizures, difficulty breathing, or vomiting 2

Critical timing consideration: Survival rates are significantly higher when gastric decontamination occurs within 2 hours of exposure (97.87% vs 84.62%). 5 However, the clinical picture often shows a conspicuous absence of symptoms during the first 24 hours, with toxidrome manifestation occurring after a lag period of 24-36 hours (range 18-72 hours). 5

What NOT to Do (Common Pitfalls)

Avoid these interventions in late presentations:

• Do NOT give activated charcoal, ipecac, or perform gastric lavage once absorption has occurred—these are ineffective and delay definitive care 2, 3
• Do NOT administer milk or water for dilution unless specifically advised by poison control—insufficient evidence of benefit and may cause emesis and aspiration 2
• Do NOT delay supportive care while awaiting specific rodenticide identification 2, 3

Type-Specific Management

Anticoagulant Rodenticides (Most Common: Brodifacoum, Bromadiolone, Diphacinone)

These "superwarfarins" have extremely high affinity for vitamin K epoxide reductase compared to warfarin, characterized by rebound coagulopathy after initial treatment. 6

Clinical presentation:

• Most common bleeding sites: mucocutaneous, with hematuria being the most frequent feature 6
• CNS hemorrhage (subarachnoid hemorrhage, intracerebral hematoma) is rare but potentially lethal 7
• Coagulation values often beyond measurable limits (PT, aPTT prolonged; INR markedly elevated) 6, 7

Treatment approach:

• Acute hemorrhagic symptoms: IV vitamin K1 in excess of 50-100 mg is often required 6
• Chronic maintenance: 100 mg PO vitamin K1 daily is the most frequently used dose to suppress coagulopathy 6
• Treatment duration: Averages 168 days due to long half-life of these agents 6
• Adjunctive hemostatic therapy: Fresh frozen plasma for active bleeding; recombinant factor VIIa and prothrombin complex concentrate have been reported for life-threatening hemorrhage 6, 7
• Vitamin K1 at 5 mg/kg/day divided for several 5-day regimens has been effective in preventing bleeding diathesis 8

Yellow Phosphorus Rodenticides (Common in India)

This formulation dominates rodenticide poisoning in Southern India (67.2% of cases), often combined with zinc phosphide (24%). 5

Clinical manifestations (after lag period):

• Abdominal pain (52.53%), jaundice (22.21%), coagulopathy (15.15%), hepatic encephalopathy (10.10%), shock (10.10%), acute kidney injury (7.08%), multi-organ failure (17.17%) 5
• Laboratory findings: AST/ALT elevation (48-50%), bilirubin elevation (22.21%), PT/INR prolongation (15.15%), metabolic acidosis (10.12%) 5

Mortality predictors:

• Delayed resuscitation, jaundice, hepatic encephalopathy, AST/ALT >1000 IU/L, metabolic acidosis, and refractory shock 5
• Most common cause of death: fulminant hepatic failure (77.78% of deaths) 5
• Mean time to death: 4.22 days since exposure (range 2-8 days) 5

Management of Specific Complications

Intracranial hemorrhage:

• Administer benzodiazepines for seizures or agitation 2, 3
• Perform EEG monitoring for non-convulsive seizures in patients with altered mental status 2, 3
• Surgical intervention may be required for significant intracerebral hematoma with midline shift 7
• Mannitol for brain edema management 7

Coagulopathy management:

• Monitor PT, aPTT, INR, and coagulation factors II, VII, IX, and X 8
• Correct coagulation disorders with vitamin K and fresh frozen plasma 7
• Monitor for rebound coagulopathy—vitamin K inhibition can persist for approximately 30 days 8

Metabolic derangements:

• Monitor and correct metabolic acidosis, which predicts poor outcome 2, 5
• Monitor renal function for acute kidney injury 5

When to Consult Medical Toxicology

Mandatory consultation scenarios:

• Complex presentations with multiorgan bleeding 2
• Late presentations with established coagulopathy 2
• Fulminant hepatic failure 5
• Intracranial hemorrhage requiring neurosurgical intervention 7

Monitoring and Follow-Up

• Perform hemograms and biochemical profiles every other day 8
• Continue coagulation monitoring throughout vitamin K therapy and for weeks after discontinuation 6, 8
• Bleeding can be observed up to 2 weeks after initial treatment in anticoagulant rodenticide poisoning 8
• Post-treatment monitoring is critical—strengthen diagnosis and surveillance for late complications 7