Signs of Oxycodone Abuse. Other than a drug test, one can use the following symptoms to detect oxycodone or OxyContin abuse: 1  Drowsiness, sometimes to the point of nodding off. 2  Sedation. 3  Euphoria. 4  Lightheadedness. 5  Itching. 6  Nausea and vomiting. 7  Constipation. 8  Low blood pressure. 9  Respiratory suppression. 10  Headache. 11  Dry mouth. 12  Sweating.