Oxymorphone and oxycodone are both strong opioids medicines used to prevent severe pain.oxymorphone is stronger than oxycodone.oxymorphone can work better for people who have very bad pain that other medicines cannot fix.oxymorphone is more powerful so that doctors usually give it to people who need extra help managing their pain.Oxycodone is also strong and helps many people with pain, but it is not as strong as oxymorphone. Both medicines can be useful depending on how much pain a person has.Over doses of Oxymorphone can cause side effects like feeling very sleepy, dizzy, or having problems with breathing .Misuse of both medications can be dangerous and it also causes addiction so it is important to use them exactly as the doctor suggestion.