(CBS NEWS) Officials are investigating 13 deaths over the past four years that may be tied to 5-hour Energy, the Food and Drug Administration confirmed on Wednesday.
FDA records obtained by the New York Times show that since 2009 there have been 90 filings against the caffeinated shots, including more than 30 which were deemed serious or life-threatening. Symptoms included heart attacks, convulsion and one case of spontaneous abortion.
"We take every adverse event report seriously," Shelly Burgess, an FDA spokeswoman, said to the Wall Street Journal.
Burgess confirmed that the reports were filed by the company themselves.
5-hour Energy drinks are sold in 1.9-ounce containers known as shots. While they don't label how much caffeine is in their bottles, a Consumer Reports investigation claimed that it could range from 6 mg in their 5-hour Decaf bottles to 242 mg in their 5-hour Energy extra strength bottles.
This isn't the first time energy drinks have been under scrutiny from the FDA. In late October, the organization announced they were investigating five deaths and one heart attack tied to Monster Energy drinks since 2004. Around that time, the parents of 14-year-old Anais Fournier, a girl who allegedly died after drinking two Monster Energy drink beverages within 24 hours, said they were suing the drink maker for failure to label the risks of drinking their product.
Energy drinks growing popularity has some health officials concerned. The Substance Abuse and Mental Health Services Administration reported that energy drink-related emergency room visits increased tenfold from 2005 to 2009. In 2008 and 2009, there were 16,053 and 13,114 cases respectively. Two-thirds of the cases were deemed "adverse reactions."
About 52 percent of the visits were by patients between the ages of 18 to 25 who had used the energy drinks with alcohol or other drugs. Men were more likely to go to the emergency room, and their visits were more likely to be related to a combination of the energy drink with alcohol or illicit drugs. Females were more likely to visit due to a combination of energy drinks and pharmaceuticals.
However, Cleveland Clinic cardiac surgeon Dr. Marc Gillinov previously told CBSNews.com that in order to die from caffeine overdose, one would have to consume 10 grams of caffeine. For comparison, a tall cup of Starbucks brewed coffee is has about 260 milligrams of caffeine, while an average cup of tea only has 40 milligrams.
In a statement, 5-hour Energy makers Living Essentials LLC claimed that its product was a "compact-sized energy shot intended for busy adults," not an energy drink or beverage. They said that each product contains about the same amount of caffeine as a cup of premium coffee and can be used as a dietary supplement if followed using their recommended use guidelines.
In addition, the company stressed the product should not be used in conjunction with alcohol, and consumers should not drink more than two bottles a day spaced several hours apart.