Episode 908: Sympathomimetic Drugs

Emergency Medical Minute

Contributor: Taylor Lynch MD

Educational Pearls:

• Overview:
  • Sympathomimetic drugs mimic the fight or flight response, affecting monoamines such as dopamine, norepinephrine, and epinephrine
  • Limited therapeutic use, often abused.
• Types:
  • Amphetamines: Methamphetamine, Adderall, Ritalin, Vyvanse
  • MDMA (Ecstasy)
  • Cocaine (Both hydrochloride salt & free based crack cocaine)
  • Theophylline (Asthma treatment)
  • Ephedrine (For low blood pressure)
  • BZP, Oxymetazoline (Afrin), Pseudoephedrine (Sudafed)
  • MAO Inhibitors (treatment-resistant depression)
• Mechanisms:
  • Act on adrenergic and dopaminergic receptors.
  • Cocaine blocks dopamine and serotonin reuptake.
  • Methamphetamines increase stimulatory neurotransmitter release
  • MAO Inhibitors prevent neurotransmitter breakdown.
• Symptoms:
  • Agitation, tachycardia, hypertension, hyperactive bowel sounds, diuresis, hyperthermia.
  • Severe cases: Angina, seizures, cardiovascular collapse.
• Diagnosis:
  • Clinical examination and history.
  • Differentiate from anticholinergic toxidrome by diaphoresis and hyperactive bowel sounds.
  • Tests: EKG, cardiac biomarkers, chest X-ray, blood gas, BMP, CK, coagulation studies, U-tox screen.
• Treatment:
  • Stabilize ABCs, IV hydration, temperature monitoring, benzodiazepines.
  • Avoid beta-blockers due to unopposed alpha agonism.
  • Whole bowel irrigation for body packers; surgical removal if packets rupture.
  • IV hydration for high CK levels.
  • Observation period often necessary.
• Recap:
  • Mimic sympathetic nervous system.
  • Key symptoms: Diaphoresis, hyperactive bowel sounds.
  • Treatment: Supportive care, benzodiazepines.
  • Use poison control as a resource.

References:

1. Costa VM, Grazziotin Rossato Grando L, Milandri E, Nardi J, Teixeira P, Mladěnka P, Remião F. Natural Sympathomimetic Drugs: From Pharmacology to Toxicology. Biomolecules. 2022;12(12):1793. doi:10.3390/biom12121793

2. Kolecki P. Sympathomimetic Toxicity From Emergency Medicine. Medscape. Updated March 11, 2024. https://emedicine.medscape.com/article/818583-overview

3. Williams RH, Erickson T, Broussard LA. Evaluating Sympathomimetic Intoxication in an Emergency Setting. Lab Med. 2000;31(9):497-508. https://doi.org/10.1309/WVX1-6FPV-E2LC-B6YG

Summarized by Steven Fujaros | Edited by Jorge Chalit, OMSIII