Guaifenex and panic attack

My son is 25 and he started takng Guaifenex back in June for sinus infection. Since then he has been to emergency room 3 times and in the hospital twice--complains of pressure in upper jaw, chest tightness, and has chilling sensation along spine. Also his left side feels funny and he has been diagnosed with panic attacks and the doctor wants him to have a phsyc examination--he's not crazy just wants these wierd symptoms to go away. Has anyone had any long term affects after taking this drug?

My dr prescribed me Guaifenex PSE 600/60 and Z-pack antiobiotics for my tonsillitis. I must say the Guaifenex really helps my sinus drainage but I cannot sleep at all. Here it is 3am and I am not one bit tired. Also, it seemed to trigger panic attacks. Overall, seems to work well but the side effects are killin me.