Toxodromes

A toxidrome (toxic syndrome) is a specific constellation of clinical signs and symptoms caused by an overdose or exposure to a particular class of toxins or drugs. There are five major toxidromes:

Sympathomimetic

This toxidrome involves overstimulation of the sympathetic nervous system, mimicking the body's “fight or flight” response.

Common Agents
- Cocaine
- Amphetamines
- Methylphenidate (Ritalin/Adderall)
- MDMA (Ecstasy)
- Bath salts
Key Symptoms
- Agitation, anxiety, paranoia, hyperactivity, tremors, and seizures.
Vital Signs & Exam
- tachycardia
- hypertension
- hyperthermia
- diaphoresis
Eye Findings: Mydriasis

Anticholinergic

This occurs when drugs block the action of acetylcholine in the parasympathetic nervous system.

Common Agents
- Atropine
- Antihistamines
- Tricyclic antidepressants (TCAs)
- Plants like Jimson weed.
Key Symptoms
- Delirium, hallucinations, confusion
- Muscle twitching.
- Classic mnemonic: “Mad as a hatter, blind as a bat, red as a beet, hot as a hare, dry as a bone.”
Vital Signs & Exam:
- Tachycardia
- Hyperthermia
- Dry skin and mucous membranes (no sweating)
Eye Findings: Miosis

Cholinergic

This toxidrome is caused by overstimulation of parasympathetic nerves due to an excess of acetylcholine.

Common Agents
- Organophosphates (pesticides)
- nerve agents (e.g., Sarin)
- Meds like physostigmine.
Key Symptoms:
- Mnemonic “SLUDGE: Salivation, Lacrimation, Urination, Diarrhea, Gastrointestinal cramps, and Emesis”
- Severe cases cause pinpoint pupils, muscle fasciculations, and respiratory distress.
Vital Signs & Exam:
- Profuse bodily secretions
- Bradycardia
Eye Findings: Miosis

Opioid

This toxidrome suppresses the central nervous system, mainly through the activation of mu-opioid receptors.

Common Agents
- Opioids: Morphine, heroin, fentanyl, oxycodone, and codeine
Key Symptoms:
- CNS depression ranging from extreme drowsiness to unresponsiveness or coma.
Vital Signs & Exam:
- Bradypnea
- Hypotension
- Hypothermia
Eye Findings: Miosis

Sedative-Hypnotic

This syndrome results from the enhancement of GABA receptors, which generally slows down brain activity.

Common Agents:
- Benzodiazepines (e.g., Valium, Xanax)
- Barbiturates,
- Ethanol
- Sleeping aids (Z-drugs)
Key Symptoms
- Drowsiness, slurred speech, confusion, and ataxia
Vital Signs & Exam:
- Depressed breathing
- Hyporeflexia
- Hypotension
Eye findings: generally not a feature of this toxidrome.

Resources

drugs

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