Anesthesia & Analgesia, Vol 80, 86-91, Copyright © 1995 by International Anesthesia Research Society
Postoperative analgesia after co-administration of clonidine and morphine by the intrathecal route in patients undergoing hip replacement
D Grace, H Bunting, KR Milligan and JP Fee
Queen's University of Belfast, Department of Anaesthetics, Northern Ireland.
Postoperative analgesia after intrathecal co-administration of clonidine
hydrochloride (75 micrograms) 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 under
bupivacaine spinal anesthesia. Patient-controlled morphine requirements
were significantly reduced (P < 0.001) postoperation by both
clonidine/morphine (median 5 mg/24 h) and morphine (median 7 mg/24 h)
compared with control (saline) (median 28 mg/24 h). However, no significant
additional reduction in postoperative analgesic requirements was shown with
the clonidine/morphine combination compared with morphine alone. Visual
analog pain scores, although good in all groups at all times, were
significantly poorer in the control group at 2 h (P < 0.04) and 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 pressure
was significantly lower in the clonidine/morphine group than in the two
other groups (P < 0.001) between 2 and 5 h after operation. The
incidence of emesis was similar in the clonidine/morphine and morphine
groups and was significantly more than in the control group.
