My 16y/o daughter was prescribed Guaifen DM for a sinus problem. ...

My 16y/o daughter was prescribed Guaifen DM for a sinus problem. She took twice on the first day, the next morning she took one, went to school and at 10:30 I got a phone call at work that she was on her way to the hospital by ambulance for a severe allergic reaction. She had a severe rash all over, tremors (almost like a seizure), swollen throat and tongue. It took about 4 days for the tremors to go away. Ten days later, she experienced another bout of extreme tremors, we went to the Emergency room where the ER Doc said that there was no way that those meds were causing her problems. Now they want to do a MRI and an EEG. I really think that this med is extremely dangerous and has caused all the problems. How long has it been on the market??????