The Effect of Adding Nalbuphine to Intrathecal Morphine on Analgesic Efficacy and Side Effects After Cesarean Section

38 patients of this group will receive 10 mg of 0.5% hyperbaric bupivacaine (Buvanest Spinal 0.5% Heavy) with 0.2 mg morphine (Infumorph - Injection 10 mg/mL) in 0.5 ml volume (total volume 2.5 mL). Patients will be preloaded with 10 ml/kg Ringer's lactate solution intravenous.

39 patients of this group will receive 10 mg of 0.5% hyperbaric bupivacaine (Buvanest Spinal 0.5% Heavy) with 0.5 mg morphine (Infumorph - Injection 10 mg/mL) plus 0.2 mg nalbuphine (NALUFIN 20MG/ML AMP) in 0.5 ml volume (total volume 2.5 mL). Patients will be preloaded with 10 ml/kg Ringer's lactate solution intravenous.