Case 14 – Restless Driver

Case #14: Restless Driver
Author: Michael Gottlieb, MD
Peer Reviewer: Jenny Lu, MD

A 51 year old male truck driver with past medical history of hypertension, diabetes, and hyperlipidemia presents with palpitations and insomnia for the past 2 days. He presented to the local ED while driving cross-country delivering packages. He notes that the palpitations began about two days ago and that the subsequent night, he felt anxious and was unable to sleep. He notes mild nausea, but his review of systems is otherwise negative. He currently takes Nifedipine, HCTZ, Metformin, Glipizide, and Simvastatin. He drinks 2-3 “small” cups of coffee/day, smokes ¼ pack of cigarettes/day, and denies alcohol or illicit drug use. His physical exam is significant only for mild tremors and a tachycardia with regular rhythm. A CBC and BMP were sent from triage, which were within normal limits.

Vitals: Temp: 98.2, HR: 124, RR: 12, BP: 138/86, O2 sat: 98% on RA

What is the most likely etiology of this patient’s presentation?
This scenario underscores the importance of obtaining a good history of over-the-counter (OTC) medications including energy drinks. In a truck driver who develops new onset palpitations, there is a broad differential (PE, Anxiety, Hyperthyroidism, etc). However, his work-up for organic causes ended up negative and upon further questioning, he endorsed drinking four “energy drinks” per day to help him stay awake for the long trips. The energy drinks contained both 5 times the amount of caffeine contained in coffee and significant amounts of guarana (a compound containing nearly twice the caffeine content as coffee beans).
What other clinical symptoms might you expect to see in a patient who has ingested excessive amounts of caffeine?
CNS: Headache, Agitation, Tremors, Insomnia, Seizure
CV: Tachycardia, Hypo/hypertension, Atrial and ventricular arrhythmias
GI: Nausea, Vomiting
GU: Increased urination
MSK: Rhabdomyolysis
Metabolic: Hyperthermia, Hyperglycemia, Hypokalemia (secondary to the beta-agonism), Metabolic acidosis
What is the initial treatment for this patient?
Due to caffeine’s relatively rapid absorption, treatment is predominately symptomatic. Benzodiazepines are first line for the treatment of agitation and anxiety. Tachycardia may be managed with a beta-blocker. Nausea and vomiting can be treated with Ondansetron (Note: AVOID phenothiazines, like Prochlorperazine/Promethazine, due to the risk of lowering the seizure threshold). Seizures (seen more commonly with the Caffeine analog, Theophylline) may be very difficult to control and should be treated initially with benzodiazepines.
Just as you are leaving the room, the nurse informs you that the Theophylline level (mistakenly ordered from triage) came back elevated. The patient denies taking Theophylline at any time. How are Theophylline levels correlated with caffeine intake?
Caffeine overdose can cause a false elevation of theophylline levels.
What is the disposition for these patients?
Most patients may be safely discharged as long as they remain relatively asymptomatic after 6 hours.


Jabbar SB, Hanly MG. Fatal caffeine overdose: a case report and review of literature. Am J Forensic Med Pathol. 2013 Dec;34(4):321-4.

Smith A. Effects of caffeine on human behavior. Food Chem Toxicol. 2002 Sep;40(9):1243-55.

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