What Causes Sudden Mental Instability?

my wife has a chronic cough, she has been to the ER four times in the last two weeks, The next to last visit the prescribed her three different medications, Acetaminophen-codeine 300,Ventolin HFA 90 inhaler, methylpresdnisolone 4mg. She took these medications one day before I took her back to the hospital. she is now itching everywhere, swollen face and neck area, and has lost all of her mental thoughts. The doctors tell me that this is not a side effect to the medication but because she has pneumonia. she also has kidney failure, and missed treatment twice. They say it is nothing to worry about. She does not know who she is, where, when, or can hold a conversation with you.