Do Stimulants in Energy Drinks Provoke Seizures?

BOSTON—The consumption of energy drinks and other beverages that contain caffeine and other stimulants has been implicated in causing adverse CNS effects, such as seizures and cerebral vasculopathy. According to research presented at the 59th Annual Meeting of the American Academy of Neurology, large amounts of energy drinks may induce seizures in genetically susceptible persons, especially if they are taken on an empty stomach.

“Given the fact that a large number of young adults consume energy drinks without having seizures, it is likely that these drinks may reduce the seizure threshold in a dose-dependent pattern, and in genetically susceptible individuals,” stated Stanley Jones P. Iyadurai, MD, PhD, and Steve S. Chung, MD, both of the Barrow Neurological Institute at St. Joseph’s Hospital and Medical Center in Phoenix.

The researchers compiled a case series of four patients, ages 19 to 28, who experienced seizures associated with heavy consumption of energy drinks, including Red Bull®. None of the patients had any evidence of intracranial or EEG abnormalities, and no patient had headaches prior to the seizures, although one had migraines, and another had complex migraines. One patient, a previously healthy 25-year-old male, had been admitted to the emergency room for two seizure episodes four months apart. The first lasted about one minute, the second was twice as long, and both episodes were followed by postictal confusion for 10 minutes. The patient had no history of head trauma or seizure and no family history of seizure, and he denied experiencing any seizure-provoking factors, such as sleep deprivation, excessive caffeine intake, illicit drug use, fever, or infection.

However, the patient reported that he had consumed two 24-oz bottles of the energy drink Rockstar® on an empty stomach, approximately 30 to 60 minutes prior to both seizures; in addition, he had consumed another brand of energy drink, Monster®, on an empty stomach prior to his first seizure. He also claimed to have regularly consumed 16-oz energy drinks three to four times a week. Six months after being told to abstain from consuming energy drinks, the patient claimed not to have experienced any further seizure activity.

The common ingredients contained in the two energy drinks consumed by the patient were taurine, guarana seed extract, caffeine, inositol, carnitine, and vitamins. Although no clear correlation between seizures and energy drinks has been found, three of the ingredients—caffeine, taurine, and guarana seed extract—have been linked to adverse neurologic events in humans and in animals. Guarana seed extract contains guaranine, a mixture of methylxanthines (caffeine, theophylline, and theobromine), which stimulate the cardiac and central nervous systems. In addition, animal studies have suggested that taurine has both anticonvulsant and epileptogenic properties, although its effect on humans is not fully understood. Excessive caffeine consumption has been shown to result in increased seizure incidence and a lower seizure threshold in humans.

“While it is tempting to assign a causal relationship between high-volume consumption of energy drinks and new-onset seizures, it should be borne in mind that our study is limited by small sample size and may reflect the possibility of a coincidental association or selective retrospective blame, provoked by questioning,” Drs. Iyadurai and Chung pointed out. In addition, the four patients did not have seizures when they consumed energy drinks in low quantities, “which suggests that these stimulants impose a dose-dependent effect,” the investigators stated.           

NR