North Texas Research Forum 2024



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North Texas


Medical City Weatherford


Internal Medicine

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Publication Date



clenbuterol, toxicity, performance enhancing drugs, drug-related side effects and adverse reactions


Internal Medicine | Medicine and Health Sciences


Introduction: Clenbuterol is a medication that is relatively unknown outside of the equestrian and bodybuilding worlds. It acts as a sympathomimetic compound with beta-2 agonism and can cause tachycardia and bronchodilation. It is utilized for this bronchodilation as a means of improving equestrian performance. Its sympathomimetic effects were utilized in the bodybuilding community as a weight loss medication by increasing catabolic metabolism. Here we present a case of intentional clenbuterol toxicity for weight loss. Case presentation: A 34-year-old woman with past medical history of migraines presented to the emergency department for evaluation of palpitations and an EKG showed sinus tachycardia of 120, normal axis, prolonged QTc of 493 ms, ST depressions in II, III, aVF, and V3-V6. Laboratory evaluation which show a serum potassium of 2.2 and her sinusoidal baseline was determined to be due to beer hypokalemia. She had access to clenbuterol from training horses and had utilized it as a weight loss medication cycling for 2 weeks of daily use in 4 weeks without. She had taken approximately 225 mcg and toxicology studies for acetaminophen, salicylates, ethanol, and urine drug screen were only positive for tetrahydrocannabinol. She was monitored in the progressive care unit with aggressive potassium replacement before being discharged after resolution of her sinus tachycardia. Discussion: Clenbuterol toxicity has been associated to myocardial ischemia and rhabdomyolysis. The etiology of myocardial ischemia is due to increased myocardial oxygen demand from unopposed beta agonism. The sympathomimetic toxidrome can be prolonged due to its half-life of 36 hours. Through beta agonism induced shifts of potassium intracellularly, rhabdomyolysis can occur. It is important to consider alternative toxicities when a prolonged sympathomimetic toxidrome occurs.

Original Publisher

HCA Healthcare Graduate Medical Education

Stop Horsing Around: A Case of Cenbuterol Toxicity



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