I have had very adverse reactions when taking codeine, both as pills and in a cough medicine. I am in need of a total knee replacement and have a concern about which pain medicines will work for me with such an aversion to codeine and morphine meds. Reaction I had was to go into a sleep state similar to a coma where I could hear people around me but could not move any part of my body. Family thought I was sleeping but I was clearly awake but could not move any part of my body. Thanks for your input.