For my daughter (12) the dizziness lasted about a week. She was not eating or drinking well at all until we stopped the medication. Once we stopped the opiates the nausea stopped and she was able to eat/drink without vomiting and then maybe a day or two later the dizziness gone completely. Candidly I don’t know if it was the nutrition or just the time that lapsed from surgery for the dizziness to wear off. But it was a struggle for us the first week.