Sympathomimetic toxidrome
Formal Definition
A clinical toxidrome resulting from exposure to sympathomimetic agents (substances that stimulate alpha- and/or beta-adrenergic receptors) — including cocaine, methamphetamine, MDMA ("ecstasy"), synthetic cathinones ("bath salts"), and certain prescription drugs used inappropriately (pseudoephedrine, methylphenidate at high doses); characterized by the triad of CNS stimulation (agitation, hypervigilance, tremors, seizures), cardiovascular hyperactivity (tachycardia, hypertension, hyperthermia, chest pain, vasospasm), and metabolic derangement (hyperthermia, diaphoresis, lactic acidosis, hyperglycemia); management focuses on supportive care, benzodiazepines for agitation/seizures, cooling for hyperthermia, and avoidance of pure beta-blockers (unopposed alpha effect in cocaine).
How It's Used on the Ward
"Sympathomimetic toxidrome" or "upper toxidrome" — the textbook constellation of agitation, tachycardia, hypertension, hyperthermia, and sweating in a patient who took cocaine, meth, MDMA, or bath salts; classic ED presentation of a tachy, hypertensive, agitated patient with dilated pupils; treat with benzodiazepines, NOT pure beta-blockers (risk of unopposed alpha effect).
Example
""32-year-old brought to ED by EMS after snorting cocaine, found agitated, diaphoretic, complaining of crushing chest pain. T 38.9°C, HR 162, BP 210/118, RR 26, SpO2 99%, dilated pupils 6mm bilaterally. ECG: 2mm ST elevation in V1-V3, hyperacute T waves. Troponin 4.8. Diagnosis: sympathomimetic toxidrome from cocaine with cocaine-induced vasospasm causing STEMI. Treatment: ASA 325mg, IV nitroglycerin, IV benzodiazepines (lorazepam 2mg) for both agitation and to reduce cocaine-induced vasospasm. Cardiology consulted for emergent cath; mild cocaine-induced coronary vasospasm without occlusion — treated medically, stenting deferred.""
Clinical Context
Differential by exposure and pharmacology: cocaine (blocks norepinephrine and dopamine reuptake — also causes coronary vasospasm); methamphetamine/MDMA (reverse transport — release neurotransmitters); synthetic cathinones ("bath salts" — MDR-3, MDPV, alpha-PVP — variable effects, can cause severe psychosis, hyperthermia, organ failure); prescription sympathomimetics (pseudoephedrine, methylphenidate — overdose pattern). Key clinical pearls: (1) cocaine-induced chest pain — treat with benzodiazepines first (anxiolysis + vasospasm reduction) before nitroglycerin; avoid beta-blockade alone (unopposed alpha with worsening vasospasm — beta blocker + alpha blocker like carvedilol/labetalol theoretically may be acceptable, though pure beta like metoprolol is contraindicated). (2) Hyperthermia is the biggest driver of mortality — aggressive cooling (cold fluids, ice packs, cooling blankets). (3) Severe agitation → restraint, IV lorazepam, possibly intubation to control for safety. (4) Watch for end-organ damage — rhabdomyolysis, AKI, MI (vasospasm + dissection), stroke (vasospasm vs hemorrhage vs hypertensive emergency), mesenteric ischemia. (5) Chronic methamphetamine use — cardiomyopathy, pulmonary hypertension, dental disease ("meth mouth"), psychiatric complications.