Key features of serotonergic toxidrome
Note: Severe serotonergic toxidrome is a medical emergency and progresses to life-threatening multiorgan failure if not treated promptly.
Serotonergic toxidrome (also known as serotonin toxicity) develops within hours of:
- commencing or increasing the dose of a serotonergic drug
- poisoning with a serotonergic drug
- interaction between serotonergic drugs.
Serotonergic toxidrome is best described as a spectrum of severity (ie not serotonin syndrome). It is characterised by a triad of clinical effects:
- neuromuscular excitation—hyperreflexia, clonus (inducible or spontaneous), ocular clonus, myoclonus, shivering, tremor, hypertonia, rigidity
- autonomic effects—hyperthermia (temperature more than 39ºC or rapidly rising), sweating, flushing, mydriasis, tachycardia
- central nervous system (CNS) effects—agitation, anxiety, confusion, altered conscious state. Delirium is not prominent.
Management of serotonergic toxidrome focuses on supportive care, gentle sedation, cooling, and sometimes antidotal therapy.