ABSTRACT
The present study included fourty male patients, their ages ranged between 20 to 40 years, submitted to lower abdominal extraperitoneal operations. They were given either intrathecal or intramuscular morphine to relieve post-operative pain. The study was designed to compare the effect of systemic and intrathecal morphine and to demonestrate the effect of serum sodium on morphine analgesia in both groups. Intrathecal morphine was found to be a safe and reliable method. The intrathecal route was considered to be superior than the intramusclar route. As intrathecal, morphine was smaller in dose, it produced more prolonged duration with minimal complications. Clinically measured serum sodium was found to have no effect on the effeciency of morphine analgesia