After taking Mucinex DM I have developed a skin rash on my upper body. Is this common?

My husband had this occur to him also.The physician said it was an allergic reaction,and told him to stop taking it.He had a whole body rash before he went to the physician.I would stop taking it,and if it is bad,call your physician.|||You are having an allergic reaction. Stop taking it and see your doctor if it doesn't go away.