Feet swelling as side effect of opiate addiction?

Probably. Feet swelling can be from multiple reasons. Opiate users usually have multiple systems injured in their body and self-care may be diminished. Medications for treatment of opiate addiction, like methadone, can also produce side effects. Have a doctor check you legs and review your health conditions and risk factors. Avoid injecting the legs b/c high risk for dvt/ blood clots. Get treatment.