What Are The Side Effects Of Excess Intake Of Robitussin?

Hi Dr. I wander if you could share with me what consequences can bring to a 67 yrs.old man who regularly takes up to 60 capsules of Robutissen a day. I work in a shelter for men and one of our clients share with me that he takes the pills for his caugh but I have observed he gets very high and says he feels very hot although it is minus 10 degrees today. I am very concerned about the side effects of his abuse on this medication that he buys directly from the counter. Please advice. Thanks for your reply.