Order Codeine Online Opioid Pain Relief Medicines At Arkansas, United state . is an opioid medication that is used to treat mild to moderate pain, cough, and diarrhea. It works by altering the way the brain and nervous system respond to pain and other stimuli. Codeine is often combined with other pain relievers like acetaminophen or aspirin to treat pain such as headaches, back pain, or post-surgery discomfort. It can be found in some cough syrups, as it helps reduce coughing by acting on the brain's cough center.