SNRI Toxicity

Background

  • Inhibits reuptake of serotonin, norepinephrine and small effect on dopamine
  • Adverse effects similar to SSRIs
  • Venlafaxine (Effexor)
    • Can produce mild to moderate hypertension
  • Duloxetine (Cymbalta)
    • Nausea, vomiting, dizziness

Clinical Features

  • Sympathomimetic: tachycardia, hypertension, diaphoresis, tremor, mydriasis
    • Secondary to inhibition of norepinephrine reuptake
  • Sedation
  • Seizures
  • Rhabdomyolysis
    • 25% occur without seizures
  • ECG
    • Most common abnormality: sinus tachycardia
    • May see QRS widening or QT prolongation

Evaluation

  • Suggestive history with appropriate clinical features

Management

  • Cardiac monitoring
  • Supportive Care: IV fluids for hypotension, Benzodiapazines for seizures
  • Consider single dose activated charcoal


Disposition

  • Admit all symptomatic patients to a monitored bed
  • Monitor for 6 hours, longer for extended-release preparations

See Also

References

  • Mills K. Atypical Antidepressants, Serotonin Reuptake Inhibitors, and Serotonin Syndrome In: Tintinalli's Emergency Medicine. 7th ed. McGraw Hill. 2011:1198-2002