Some doctors say drinks that combine alcohol with caffeine should be banned because they're dangerous, ABC News reported Oct. 20.

Marketed in large, colorful cans under names like Four Loko, Joose, and Torque, the drinks are popular among college students. The 23.5-ounce canned drinks can contain 12 percent alcohol and 156 milligrams of caffeine, and have encountered increasing criticism. Attorneys general in more than one state are concerned that they're being marketed to minors, a New Jersey college banned them, and the Food and Drug Administration (FDA) is deciding whether or not the drinks are legal. 

Dr. Robert McNamara, who directs the emergency medicine department at Temple University, recently encountered his first-ever case of a healthy 19-year-old whose heart attack seemed to be linked to consuming alcoholic energy drinks. “This is a dangerous product from what we've seen,” McNamara said, who said other doctors had told him about similar cases. “It doesn't have to be chronic use. I think it could happen to somebody on a first time use.”

“I'm mad as hell,” said Doctor Mary Claire O'Brien of Wake Forest University. “These drinks are not safe.”

O'Brien, who is a professor of emergency medicine and public health, recently completed a study that showed that consuming alcohol with caffeine was more harmful than drinking alcohol alone. Those who consumed both were at least two times as likely — compared to those drinking alcohol without caffeine — to be hurt, need medical attention, take sexual advantage of another, or accept a ride with someone who was inebriated.

“They can't tell that they're drunk,” O'Brien explained. “What this behavior gets is a wide awake drunk.”

The FDA has said that, under regulations governing food additives, caffeine can't be mixed with alcohol. It is currently evaluating whether the drinks should remain legal, but no deadline has been set for a decision.

“FDA intends to evaluate the information submitted by the manufacturers and other available scientific evidence as soon as possible in order to determine whether caffeine can be safely and lawfully added to alcoholic beverages,” said Michael Herndon, a spokesman for the FDA.

Phusion Projects, which manufactures Four Loko, told ABC News, “No one is more upset than we are when our products are abused or used unlawfully. But Four Loko is neither the sole contributor to alcohol abuse, nor will additional restrictions on it solve the problem.”