Episode 908: Sympathomimetic Drugs

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