What is the management protocol for a patient who has ingested tetramine rodenticide?

Management of Tetramine Rodenticide Poisoning

Immediately secure the airway, administer high-dose benzodiazepines for seizure control, and if seizures persist despite benzodiazepines, escalate to ketamine or barbiturates—tetramine is a potent GABA antagonist with no specific antidote and mortality depends entirely on aggressive supportive care. 1, 2, 3

Immediate Life-Threatening Management

Airway and Breathing

• Secure the airway immediately with endotracheal intubation in patients with status epilepticus or reduced consciousness, as tetramine causes severe CNS depression and refractory seizures 4, 3
• Provide bag-mask ventilation prior to intubation if respiratory depression is present 4
• Tetramine has extremely potent effects on the brain stem with human oral toxicity as low as 0.1 mg/kg, making rapid deterioration common 2

Seizure Control Algorithm

• First-line: Benzodiazepines (lorazepam 0.1 mg/kg IV or diazepam 0.15 mg/kg IV) for initial seizure control 4, 3
• Second-line: If benzodiazepines fail, escalate immediately to ketamine (1-2 mg/kg IV bolus, then 0.5-5 mg/kg/h infusion), which has proven effective in tetramine-induced status epilepticus 3
• Third-line: Sodium thiopentone or propofol for refractory seizures unresponsive to benzodiazepines and ketamine 3
• Consider sodium valproate as adjunctive therapy, as it increases GABA in the CNS and may counteract tetramine's GABA antagonism 5

Critical Pitfall

• Tetramine blocks GABA-A receptors, making seizures particularly difficult to control with standard anticonvulsants alone—early escalation to ketamine is essential rather than prolonged attempts with benzodiazepines 2, 3, 5

Decontamination and Toxin Elimination

Gastrointestinal Decontamination

• Activated charcoal (1 g/kg orally) should be administered if the patient presents within 1-2 hours of ingestion and can protect their airway 4, 6
• Do not delay emergency department transport to administer activated charcoal 7
• Gastric lavage and ipecac are not recommended 7

Enhanced Elimination

• Consider high-volume hemofiltration followed by charcoal hemoperfusion in severe cases to eliminate tetramine from the body, as this combination reduced plasma tetramine levels by 63% and 25% respectively in documented cases 3
• This intervention should be performed approximately one week after poisoning once the patient is stabilized 3

Supportive Care and Monitoring

Cardiovascular Support

• Monitor for dysrhythmias and hypotension, providing vasopressor support as needed 4
• Continuous cardiac monitoring is essential as tetramine affects the brain stem and can cause autonomic instability 2

Neurological Monitoring

• Continuous EEG monitoring if available for patients with persistent altered mental status 5
• Monitor for signs of cerebral edema or increased intracranial pressure in severe cases 1

Long-Term Management and Follow-Up

Post-Acute Epilepsy Risk

• Approximately 53% of tetramine poisoning survivors develop chronic epilepsy requiring long-term anticonvulsant therapy, with an average treatment duration of 2.93 years 5
• Among those who develop epilepsy, 80% experience tonic-clonic seizures and 20% have partial seizures 5
• Sodium valproate is the preferred long-term anticonvulsant for tetramine-induced epilepsy due to its GABA-enhancing properties 5

Disposition

• All patients with suspected tetramine ingestion require immediate emergency department evaluation regardless of initial symptom severity, as deterioration can be rapid 1, 2
• Patients with intentional ingestion, any neurological symptoms, or seizures require ICU-level care 4, 1
• Even asymptomatic patients require prolonged observation (minimum 24 hours) as delayed seizures can occur 1, 2

Diagnostic Considerations

Clinical Presentation

• Generalized seizures, often progressing to status epilepticus, are the hallmark of tetramine poisoning 1, 2, 3
• Rapid progression from ingestion to convulsions and coma can occur within hours 2
• Consider tetramine poisoning in any patient with unexplained status epilepticus, particularly in regions where illegal rodenticides are available 1

Laboratory Confirmation

• Plasma tetramine levels can be measured but should not delay treatment 3
• Standard toxicology screens will not detect tetramine—specific testing must be requested 1, 2

Critical Warning

There is no specific antidote for tetramine poisoning—survival depends entirely on aggressive supportive care, rapid seizure control, and prolonged monitoring 2, 3. Early misdiagnosis is common and has resulted in preventable deaths 1. Physicians must maintain high clinical suspicion for tetramine poisoning in patients with unexplained seizures, particularly when multiple individuals are affected after sharing a meal 1, 3.