Hello, thanks for using health care magic. Hydrocodone is a semi-synthetic opioid derived from codeine and use in the management of moderate pain. When combined with paracetamol, it is used in the management of moderate to severe pains. It works by changing the way the nervous system response to pain and its dose should be strictly on prescription. Its common side effects include; nausea, vomiting, constipation, drowsiness, dizziness, light headaches, anxiety, abnormally happy or abnormally sad moods, dry throat, difficulty urinating, rash, itching etc. Severe side effects include breathing difficulties and it is particularly seen in cases of over dose. Hope this answers your question. Best regards. Dr Achuo