My Friend Has Been On Chantix For 5 1/2 Weeks.

My friend has been on Chantix for 5 1/2 weeks. She has severely slurred speech and confusion and her knees and ankles are extremely swollen. She feels kind of feverish and has a cold sweat. She just went to the doctor who prescribed it. All he said is he didn't know why it's happening and just stop taking Chantix. She is also on Xanax and and antidepressant, also phentermine. Should I be concerned, because am very much so.