DOSE-RESPONSE OF KETOROLAC AS AN ADJUNCT TO PATIENT-CONTROLLED ANALGESIA MORPHINE IN PATIENTS AFTER SPINAL-FUSION SURGERY

This randomized, blind study was designed to determine the appropriate dose of ketorolac (a drug used as a supplement to opioids) to adminis ter to patients who have undergone spinal stabilization surgery. The k etorolac was administered every 6 h, in addition to patient-controlled analgesia (PCA) with morphine, to 70 inpatients undergoing spine stab ilization by one surgeon. The study was performed to determine the ana lgesic efficacy and incidence of side effects with different doses of ketorolac. The patients were divided into seven groups. They were give n either IV saline (control group) or IV ketorolac (5, 7.5, 10, 12.5, 15, or 30 mg) every 6 h. The outcomes measured included pain scores, 2 4-h morphine usage, level of sedation, and side effect profile six tim es during the first 24 h postoperatively. The total dose of morphine w as significantly larger in the control and 5 mg ketorolac groups than in the other five groups. Morphine consumption was similar in all grou ps receiving greater than or equal to 7.5 mg of ketorolac. The pain sc ores were significantly higher in the control group than in some of th e larger dose groups at three of the study intervals. The 5 mg group h ad higher pain scores than the other groups at most of the time interv als studied. There were no significant differences in pain scores amon g the other five groups. Sedation scores were higher (i.e., patients w ere more sedated) in the control group than in the other six groups at three of the time periods. We conclude that the administration of ket orolac 7.5 mg every 6 h has a morphine-sparing effect equivalent to th at of larger doses in patients undergoing spine stabilization surgery. Using larger doses of ketorolac did not result in less somnolence, lo wer morphine use, or less pain. We recommend that ketorolac 7.5 mg be given every 6 h to patients undergoing spinal fusion surgery in additi on to PCA morphine. Implications: Using smaller doses of ketorolac (e. g., 7.5 mg every 6 h) as a supplement to morphine patient-controlled a nalgesia is as effective as larger doses in patients who have undergon e spine stabilization surgery.