Introduction to toxidromes

If the history of drug or toxin exposure is unclear or unavailable, and clinical effects do not indicate a specific poisoning, it may be possible to identify a toxidrome (toxic syndrome) from the patient’s constellation of signs and symptoms. Identifying a toxidrome can be useful to narrow differential diagnoses and direct management, but pure toxidromes are uncommon and often variable. Toxidromes may be masked by co-ingestion of multiple substances.

Toxidromes are classified according to pharmacological action:

• anticholinergic
• cholinergic
• antidopaminergic—see Neuroleptic malignant syndrome
• serotonergic
• sympathomimetic
• methaemoglobinaemia.

For the key features, causative agents and treatment of these toxidromes, see individual monographs.