is dxm overdose
Side Effects. Dextromethorphan (DXM) overdose symptoms can occur when the medication is overused, and some symptoms overlap with the normal side effects of the medication. Regular and expected side effects that may occur in patients include: 1  Dizziness. 2  Nervous behavior. 3  Drowsiness. 4  Vomiting. 5  Stomach pain. 6  Nausea. 7  Lightheadedness.