Subscribe to health news headlines email updates.
TUESDAY, Oct. 23 (HealthDay News) -- Following reports that highly caffeinated Monster energy drinks may have been linked to five deaths in the past three years, doctors are expressing concern about the large amounts of caffeine typically found in these types of beverages.
In one case, the family of a 14-year-old Maryland girl who died from an irregular heart rhythm after drinking Monster energy drinks has filed a lawsuit against the maker of the drink, Monster Beverage Co., of Corona, Calif. All five cases have been filed as "adverse event reports" with the U.S. Food and Drug Administration.
The effects of large amounts of caffeine are underappreciated, said Dr. Suzanne Steinbaum, a preventive cardiologist at Lenox Hill Hospital in New York City. "People may think that these energy drinks are healthy by the way they're marketed," she said.
There are, however, 240 milligrams of caffeine in some of these drinks, Steinbaum said. "That's seven times the amount of caffeine in a can of soda," she added.
Caffeine can increase the heart rate tremendously and drive blood pressure up, Steinbaum explained. "In anyone who has any underlying heart condition, these two effects can be deadly," she said. "Know what you're drinking before you drink it."
The FDA can't say definitively that the deaths were the result of the drinks, but an agency spokeswoman said the events are concerning.
"As with any reports of a death or injury the agency receives, we take them very seriously and investigate diligently," FDA spokeswoman Shelly Burgess said.
But, she added, "adverse event reports serve as a signal to FDA and do not prove causation between a product or ingredient and an adverse event."
Under current FDA rules, companies don't have to reveal caffeine levels in their beverages and can market them as drinks or as dietary supplements, The New York Times reported.
Burgess said manufacturers of products are required "to submit all reports on serious adverse events to [the] FDA in 15 days of receiving them."
They're also responsible for following up on cases to try to figure out the cause, Burgess said. "The follow-up in cases is usually necessary to clearly assess the relationship of the product or ingredient to the adverse event," she said.
The FDA urges anyone who thinks they've had an adverse event from a dietary supplement to contact the manufacturer or distributor listed on the label of the product, she said.
"It is important to remember that caffeine occurs in many places in the diet, and [the] FDA considers exposure to any ingredient from all sources in the diet," Burgess said.
In April, Sen. Richard Durbin, D-Ill., asked the FDA to oversee caffeine levels in energy drinks, according to the Times.
Monster, which sold $1.6 billion worth of energy drinks in 2011, defended its product, Bloomberg News reported.
"Over the past 16 years Monster has sold more than 8 billion energy drinks, which have been safely consumed worldwide," the company said in a statement. "Monster is unaware of any fatality anywhere that has been caused by its drinks."
For more on caffeine, visit the U.S. National Library of Medicine.