The number of emergency room visits involving energy drinks doubled from 2007 to 2011, reaching more than 20,000, according to a new government report. During that period, the popularity of energy drinks has surged on college campuses, and in bars and convenience stores, according to ABC News.

The report, from the Substance Abuse and Mental Health Services Administration (SAMHSA), found most cases involved teens or young adults. SAMHSA calls consumption of energy drinks a “rising public health problem.” The drinks can cause insomnia, headaches, seizures, fast heartbeat and nervousness, the report notes.

About 42 percent of emergency room cases in 2011 involved energy drinks combined with alcohol or drugs such as Adderall or Ritalin.

“A lot of people don’t realize the strength of these things. I had someone come in recently who had drunk three energy drinks in an hour, which is the equivalent of 15 cups of coffee,” American College of Emergency Physicians spokesperson Howard Mell, an ER physician outside of Cleveland, told ABC News. “Essentially he gave himself a stress test and thankfully he passed. But if he had a weak heart or suffered from coronary disease and didn’t know it, this could have precipitated very bad things.”

In November, the Food and Drug Administration (FDA) said it was likely to seek advice about the potential health dangers of energy drinks, in the wake of reports of deaths and injuries possibly related to the products. The FDA said it is considering asking advice from an outside group such as the Institute of Medicine. The agency has received reports of 18 deaths and more than 150 injuries that mention the possible involvement of energy drinks, including 5-Hour Energy, Monster Energy and Red Bull. The reports do not prove a product was responsible for a death or injury. The products’ manufacturers have said they are safe, and are not responsible for the reported deaths and injuries.