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Lamotrigine Toxicity

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Lamotrigine Toxicity, Lamotrigine Poisoning, Lamotrigine Overdose

  • See Also
  1. Lamotrigine
  • Mechanism
  1. See Lamotrigine
  • Pharmacokinetics
  1. See Lamotrigine
  • Findings
  1. Ventricular Dysrhythmia
    1. Lamictal inhibits voltage-gated Sodium channels
    2. Wide QRS Complex
      1. Treat with Sodium Bicarbonate ampules until QRS Complex narrows
  2. Serotonin Syndrome
    1. Lamictal inhibits Serotonin reuptake
    2. Serotonin Syndrome occurs in 66% with serotonergic coingestion (e.g. SSRI, SNRI)
  3. Neurologic Effects
    1. Sedation (most common finding in Overdose)
    2. Seizures
      1. Paradoxical (as Lamictal is foremost an anticonvulsant)
      2. Children may experience Seizures at doses >30 mg/kg
    3. Agitation
    4. Increased Deep Tendon Reflexes (hyperreflexia)
    5. Myoclonic Jerks
  4. Miscellaneous
    1. Nausea or Vomiting
    2. Hypotension
  • Diagnostics
  1. See Unknown Ingestion
  2. Evaluate as Unknown Ingestion
  3. Obtain other toxicologic screening including Acetaminophen level, Serum Glucose
  4. Electrocardiogram
  5. Serum Lamotrigine levels >20 ml/L are associated with severe effects (Seizures, Hypotension, intubation)
    1. High level ingestions >4g are also associated with severe effects
  • Management
  1. ABC Management
    1. Endotracheal Intubation for airway protection as needed
  2. Activated Charcoal
    1. Consider if <1 hour from time of ingestion, and patient without aspiration risk
  3. QRS Widening
    1. See above (regarding bicarbonate)
  4. Seizures
    1. See Status Epilepticus
    2. Benzodiazepines
    3. Phenobarbital
    4. Consider Propofol and intubation
    5. Consider Hemodialysis for refractory Seizures or Dysrhythmias
  5. Disposition
    1. Admit all symptomatic patients
    2. If asymptomatic at 4-6 hours after ingestion, may discharge home
  • References
  1. Tomaszewski (2020) Crit Dec Emerg Med 34(1): 28
  2. Carroll and Yakey (2025) Crit Dec Emerg Med 39(5): 38