The company's stock fell more than 5 percent in early trading. But by the end of the day on Wall Street, it had recovered all the lost ground and finished with a slight gain. Monster's stock closed the day up 7 cents, at $44.81. It dipped about 1 percent in after-hours trading to $44.30.
Federal officials said the reports to the FDA from consumers, doctors and others don't necessarily prove that the drinks caused the deaths or injuries but said they are investigating each one. In a statement, FDA officials said they could take such action as forcing the company to take the drinks off the market. The beverages often are found at convenience store checkout counters.
FDA spokeswoman Shelly Burgess said the agency is cautioning consumers that these "energy shots" or "energy drinks" are not alternatives to rest or sleep. "They should consult with their health care provider to ensure that there are no underlying or undiagnosed medical conditions that could worsen as a result of using them," Burgess said.
The agency doesn't individually regulate caffeinated drinks or supplements such as the energy shots but can take action if they are proven to do harm. Makers of caffeinated alcoholic drinks took those products off the market temporarily in 2010 after the FDA sent the companies warning letters saying that combinations of caffeine and alcohol in the drinks was a public health concern and could lead to alcohol poisoning, car accidents and assaults.
Although it is liquid, the 5-Hour Energy "shot" is marketed not as a drink but as a dietary supplement. FDA regulations require supplement manufacturers to be responsible for products' safety.
A spokeswoman for the manufacturer, Living Essentials LLC says 5-Hour Energy is a "compact-sized energy shot intended for busy adults it is not an energy drink, nor marketed as a beverage."
Democratic Sens. Richard Durbin of Illinois and Richard Blumenthal of Connecticut went to the Senate floor Thursday to complain about the lack of FDA oversight of energy drinks.