II. Causes

  1. Selective Serotonin Reuptake Inhibitor (SSRI)
    1. Most are safe in Overdose (50% are asymptomatic)
    2. Citalopram and Escitalopram in Overdose have higher risk of Seizure and EKG changes (QTc Prolongation)
      1. See Citalopram for additional cardiac related precautions in Overdose
  2. Serotonin Norepinephrine Reuptake Inhibitor (SNRI)
    1. Seizure Risk (esp. Venlafaxine)
    2. Wide QRS and QTc Prolongation
    3. Serotonin Syndrome

III. Mechanism

  1. Serotonin toxicity (e.g. Serotonin Syndrome)
    1. Any SSRI or SNRI in Overdose has the potential to cause Serotonin toxicity
  2. Sodium Channel Blockade
    1. Seen with SNRI agents and some SSRIs (e.g. Citalopram, Escitalopram)
    2. Observe for Wide QRS and QTc Prolongation

IV. Symptoms

  1. Asymptomatic in 50% of SSRI Overdoses
  2. Somnolence
  3. Nausea or Vomiting
  4. Palpitations

V. Signs: Serotonin Toxicity

VII. Diagnostics: Electrocardiogram

  1. Wide QRS (esp. SNRI Overdose)
  2. QTc Prolongation (esp. Citalopram, SNRI Overdose)

VIII. Management

  1. See Unknown Ingestion
  2. See Serotonin Syndrome
  3. Detoxification
    1. Consider Activated Charcoal if <1 hour from ingestion and patient can control airway
  4. Benzodiazepine Indications
    1. Seizures (see Status Epilepticus)
    2. Agitation
  5. Wide QRS (>120 ms)
    1. See Tricyclic Antidepressant Overdose
    2. Sodium Bicarbonate serial ampules (starting with 2-3)
  6. QTc Prolongation
    1. Correct Electrolyte abnormalities (e.g. Hypokalemia, Hypomagnesemia)
    2. Torsades de Pointes management
  7. Shock
    1. Intravenous Fluids
    2. Vasopressors (e.g. Norepinephrine)
    3. Consider ECMO in refractory shock
  8. Medical Admission Indications
    1. Seizures
    2. Wide QRS
    3. QTc Prolongation
    4. Serotonin Syndrome or other Serotonin toxicity findings
  9. Medical Clearance Indications (appropriate for psychiatry transfer)
    1. Asymptomatic patients
      1. Most ingestions after 6 hours of observation after ingestion
      2. Monitor asymptomatic Citalopram Overdoses (>400 mg ingestion) for up to 12 hours
    2. Symptomatic patients or EKG Changes (QTc Prolongation, QRS Widening)
      1. Monitor until asymptomatic and EKG normalization

IX. References

  1. Riddle and Tomaszewski (2018) Crit Dec Emerg Med 32(12): 28
  2. Tomszewski (2021) Crit Dec Emerg Med 35(12): 32

Images: Related links to external sites (from Bing)

Related Studies