A Comparative Study on Three Different Doses of Intrathecal Hyperbaric Prilocaine With Fentanyl for Optimal Dose to be Used in Elderly Patients Undergoing Day Case Lower Abdominal and Urologic Surgeries.

"Patients will be randomly allocated into the study groups according to the list of random numbers. The study groups will be as follows:~* Group P1 (N 15): patients assigned to this group will receive intrathecal 30 mg (1.5 ml) of prilocaine 2% (Takipril, prilocaine hydrochloride 20 mg/mL, hyperbar, Sintetica) + 25 ug fentanyl (0.5 ml).~* Group P2 (N 15): patient assigned to this group will receive intrathecal 40 mg (2 ml) of prilocaine 2% + 25 ug fentanyl (0.5 ml).~* Group P3 (N 15): patient assigned to this group will receive intrathecal 50 mg (2.5 ml) of prilocaine 2% + 25 ug fentanyl (0.5 ml)."