POSTOPERATIVE ANALGESIA AFTER COADMINISTRATION OF CLONIDINE AND MORPHINE BY THE INTRATHECAL ROUTE IN PATIENTS UNDERGOING HIP-REPLACEMENT

Postoperative analgesia after intrathecal co-administration of clonidi ne hydrochloride (75 mu g) and morphine sulfate (0.5 mg) was compared with analgesia produced after either intrathecal morphine (0.5 mg) or 0.9% sodium chloride in 90 patients undergoing total hip replacement u nder bupivacaine spinal anesthesia. Patient-controlled morphine requir ements were significantly reduced (P < 0.001) postoperation by both cl onidine/morphine (median 5 mg/24 h) and morphine (median 7 mg/24 h) co mpared with control (saline) (median 28 mg/24 h). However, no signific ant additional reduction in postoperative analgesic requirements was s hown with the clonidine/morphine combination compared with morphine al one. Visual analog pain scores, although good in all groups at all tim es, were significantly poorer in the control group at 2 h (P < 0.04) a nd 4 h (P < 0.001) after operation compared with both treatment groups , and significantly poorer than the clonidine/morphine group at 6 h (P < 0.002) and 24 h (P < 0.009) postoperation. Mean arterial blood pres sure was significantly lower in the clonidine/morphine group than in t he two other groups (P < 0.001) between 2 and 5 h after operation. The incidence of emesis was similar in the clonidine/morphine and morphin e groups and was significantly more than in the control group.