Legacy Emanuel Cardiologist Shawn Patrick isn't surprised the FDA is investing five-hour energy drinks. He says the drinks pack too much caffeine into a small amount of juice, making it too easy to consume a dangerous amount of the stimulant. And for people with heart problems, diagnosed or not, too much caffeine can be harmful, possibly fatal. He warns parents that “Monster Energy” drinks, a favorite among teens, have more caffeine.  The FDA also investigating 13 deaths possibly connected to the drink.