"I'm mad as hell," O'Brien said. "These drinks are not safe."
Phusion Projects says it is cooperating with the FDA and maintains its products comply with federal and state laws.
"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," said the statement.
Dr. McNamara said his 19 year-old patient will recover, but warns it could have been fatal.
"Seeing this in a young guy kind of raises your eyebrows as to whether these products should be available at all," he said.
ABC's Florinda Ricks and The Associated Press contributed to this story.