Postoperative pain is multifactorial symptom that requires a thoughtful approach using a variety of treatment modalities to obtain an optimal outcome after surgery. Multimodal analgesia represents an approach to preventing postoperative pain where the patient is administered a combination of opioid and non-opioid drugs that act at different sites within the central and peripheral nervous systems. 30 patients scheduled for major upper abdominal surgeries were allocated into 2 groups to receive multimodal analgesia continued postoperatively for three days (G1) or discontinued at the end of the procedure (G2).Plasma concentrations of metabolic substrates, serum lactate level, random blood sugar (RBS) and hormones (insulin and cortisol) will be determined. Nitrogen balance was significantly higher in (G1) compared to (G2) (p < 0.001), while the blood level of lactate in (G2) was higher than those of (G1) starting from 6 hours to 48 hours postoperatively (P<0.001), furthermore RBS was significantly higher in (G2) compared to (G1) at 48 hours postoperatively (p = 0.001), on the other hand morning serum cortisol was significantly higher in (G2) at 6, at 24 and at 48 hours postoperatively when compared with (G1) (p<0.001), serum insulin tended to decrease significantly in both groups at 6, 24 and at 48 hours postoperatively but tended to maintain its higher level in (G2) at 6,24 and 48 hours when compared with (G1). (P<0.001), VAS score was significantly lower in (G1) at all readings starting from 1 to 72 postoperative hours.In conclusion, we have shown that extension of multimodal analgesia for three postoperative days showed superior results over its restriction to the intraoperative period reflected on stress hormones, nitrogen balance and insulin levels in patients undergoing major abdominal surgeries.