Adding Nalbuphine for Control of Intrathecal Morphine Pruritus

The study will be performed in MiniaUniversity Hospitals, after obtaining approval from the local ethics committee. All patients will have a peripheral IV cannula 18 G inserted; standard non-invasive monitors will be applied. Patients undergoing major abdominal surgery will be divided into 2 groups to receive intrathecal morphine 300 micrograms with or without nalbuphine 1mg prior to anesthesia. General anesthesia is then given to patients.