Girl dies after drinking cans of Monster

(Getty Images)

When it's late and you want a pick-me-up, a hyper-caffeinated energy drink might appeal more than an espresso. But their makers face a serious setback, as the United States' Food and Drug Agency (FDA) is investigating links between Monster, which contains three times more caffeine than an 8-ounce can of Red Bull, and the deaths of five people in the last year.

Reports were released under the Freedom of Information Act after the mother of one Maryland teenager filed a lawsuit against Monster, alleging that her daughter died after drinking two large cans of the hyper-caffeinated beverage. The official autopsy said the cause of death was "cardiac arrhythmia due to caffeine toxicity".

Monster denies any blame, saying the company has sold 8 billion energy drinks over the past 16 years, with no proof tying them to any fatalities. Energy drinks are currently allowed higher levels of caffeine as they are sold as dietary supplements, not sodas.

But US Senator Dick Durbin wants to limit these levels because emergency room visits related to energy drinks soared 10-fold between 2005 and 2009 - although half of these involved drugs or alcohol too.