Table 2.

Signs and symptoms of serotonin toxicity

CATEGORYSIGNS AND SYMPTOMS
Neuromuscular

  • Tremor

  • Hyperreflexia (increased reflexes)*

  • Clonus (rhythmic muscle spasms that can be spontaneous, inducible, or ocular)*

Autonomic

  • Mydriasis (dilated pupils)

  • Diaphoresis (sweating)

  • Tachycardia (increased heart rate)

  • Tachypnea (increased breathing rate)

Mental status

  • Agitation

  • Excitement

  • Restlessness

  • Confusion

  • Delirium

  • Data from Dunkley et al,1 Boyer and Shannon,2 Ables and Nagubilli,12 and Isbister et al.13

  • ↵* Hyperreflexia and clonus are often worse in the legs than in the arms.