What are the long term side effects of taking oxycodone?

Addiction, mostly: The major side effects of opioids are constipation (which can be severe), increased sweating, weight gain, edema and hormonal changes, including reduction of testosterone and estrogen levels. These are usually dose related and are rarely seen at low doses, although it is possible. Physical dependency, which almost everyone gets if they take it in reg. Doses long enough, and addiction are issues.