Paracetamol reduces the pain signals sent to the brain and also helps to lower high temperature. It works by stopping the release of prostaglandins, which result in a decrease in pain and body temperature.
Codeine is an opiate and binds to tiny opioid receptors found all over the body in the brain, spinal cord and gut. Codeine attaches to these receptors, blocking the transmission of signals sent to the brain.
Blocking pain can help patients live a normal life again as well as increase their tolerance to pain.