ER visits after drinking energy drinks jumped from about 10,000 in 2007 to more than 20,000 in 2011, according to the latest report released by the U.S. Substance Abuse and Mental Health Services Administration.

Most of the cases involved teens, however there has been an increase in the number of people who are 40 or older seeking treatment for problems related to energy drink consumption. About 58 percent of people who visited ER during the study period had only consumed energy drinks while 42 percent had taken the drinks along with alcohol or drugs.

Recently, five people had died after drinking the popular energy drink Monster, FDA said. Few months back, 14-year-old Maryland teen died after drinking two 24-ounce Monster energy drink in a period of about 24 hours.

"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," said Howard Mell, an emergency physician and spokesman for the American College of Emergency Physicians, Associated Press reported.

The data for the study came from 230 hospitals. Between 2007 and 2011, people requiring emergency care for energy-drink related reactions were more likely to be in the 18 to 25 age group.

A recent study published in the journal Pediatrics has found that 30 to 50 percent of teenagers and young adults consumed energy drinks. Health complications like cardiac abnormalities, diabetes, seizures can occur in people who drink high amounts of these energy drinks. In 2011, sales of these drinks reached $9billion.