Energy drinks are flavored beverages containing high amounts of caffeine and typically other additives, such as vitamins, taurine, herbal supplements, creatine, sugars, and guarana, a plant product containing concentrated caffeine. These drinks are sold in cans and bottles and are readily available in grocery stores, vending machines, convenience stores, and bars and other venues where alcohol is sold. These beverages provide high doses of caffeine that stimulate the central nervous system and cardiovascular system. The total amount of caffeine in a can or bottle of an energy drink varies from about 80 to more than 500 milligrams (mg), compared with about 100 mg in a 5-ounce cup of coffee or 50 mg in a 12-ounce cola.1 Research suggests that certain additives may compound the stimulant effects of caffeine. Some types of energy drinks may also contain alcohol, producing a hazardous combination; however, this report focuses only on the dangerous effects of energy drinks that do not have alcohol.
Although consumed by a range of age groups, energy drinks were originally marketed to appeal to youths and were reported to have been consumed by 30 to 50 percent of children, adolescents, and young adults.2 Marketing suggests benefits such as increased energy and stamina, weight loss, and enhanced physical and mental performance.2 More concentrated forms of energy drinks, known as energy shots, have become increasingly popular among a wider range of age groups, including older adults.3 Marketing analysts reported increasing sales of energy shots in 2011 that were expected to continue through 2012.3 The concentrated amount of caffeine and other ingredients in these drinks has come under scrutiny as the Food and Drug Administration disclosed reports of adverse events with mention of the popular energy shot 5-Hour Energy.4
Consumption of energy drinks is a rising public health problem because medical and behavioral consequences can result from excessive caffeine intake. A growing body of scientific evidence documents harmful health effects of energy drinks, particularly for children, adolescents, and young adults.2 Research has established that, among college students, there are associations between energy drink consumption and problematic behaviors such as marijuana use, sexual risk taking, fighting, smoking, drinking, and prescription drug misuse.5,6 In one study, bar patrons who consumed alcohol mixed with energy drinks were 3 times more likely to leave a bar highly intoxicated and were 4 times more likely to intend to drive while intoxicated than those who did not consume alcohol mixed with energy drinks.6 This latter finding may be because the high levels of caffeine found in energy drinks can mask the symptoms associated with being intoxicated (e.g., feeling lethargic). Individuals, especially young drinkers, may incorrectly believe that consumption of caffeine can "undo" the effects of alcohol intake and make it safe to drive after drinking. Because of the popularity of energy drinks and the burgeoning literature suggesting the risks involved with their use, gaining additional information about these beverages is important.
The Drug Abuse Warning Network (DAWN) is a public health surveillance system that monitors drug-related emergency department (ED) visits in the United States and can be used as a source of information for assessing the more negative medical consequences associated with consuming energy drinks. To be a DAWN case, the ED visit must involve a drug, either as the direct cause of the visit or as a contributing factor. Such a visit is referred to as a "drug-related visit." Drugs include alcohol; illegal drugs, such as cocaine, heroin, and marijuana; pharmaceuticals (e.g., over-the-counter medicines and prescription medications); and nutraceuticals, such as nutritional supplements, vitamins, and caffeine products. A previous report addressing ED visits involving energy drinks was published using 2009 data7; this issue of The DAWN Report highlights trend data for energy drinks from 2007 to 2011, as well as drug combinations found in 2011.