Effect of combining dexmedetomidine and morphine for intravenous patient-controlled analgesia.
BACKGROUND
Perioperative use of dexmedetomidine is associated with reduction in postoperative analgesic requirements. This study examined whether dexmedetomidine added to i.v. patient-controlled analgesia (PCA) morphine could improve analgesia while reducing opioid-related side-effects.


METHODS
In this double-blinded, randomized, controlled study, 100 women undergoing abdominal total hysterectomy were allocated to receive either morphine 1 mg ml(-1) alone (Group M) or morphine 1 mg ml(-1) plus dexmedetomidine 5 microg ml(-1) (Group D) for postoperative i.v. PCA, which was programmed to deliver 1 ml per demand with a 5 min lockout interval and no background infusion. Cumulative PCA requirements, pain intensities, cardiovascular and respiratory variables, and PCA-related adverse events were recorded for 24 h after operation.


RESULTS
Compared with Group M, patients in Group D required 29% less morphine during the 0-24 h postoperative period and reported significantly lower pain levels from the second postoperative hour onwards and throughout the study. Whereas levels of sedation were similar between the groups at each observational time point, decreases in heart rate and mean blood pressure from presurgery baseline at 1, 2, and 4 h after operation were significantly greater in Group D (by a range of 5-7 beats min(-1) and 10-13%, respectively). The 4-24 h incidence of nausea was significantly lower in Group D (34% vs 56.3%, P<0.05). There was no bradycardia, hypotension, oversedation, or respiratory depression.


CONCLUSIONS
The addition of dexmedetomidine to i.v. PCA morphine resulted in superior analgesia, significant morphine sparing, less morphine-induced nausea, and was devoid of additional sedation and untoward haemodynamic changes.
Lin
T-F
TF
Department of Anaesthesiology, National Taiwan University Hospital, No. 7, Chung San South Road, Taipei, Taiwan, Republic of China.
Yeh
Y-C
YC
Lin
F-S
FS
Wang
Y-P
YP
Lin
C-J
CJ
Sun
W-Z
WZ
Fan
S-Z
SZ
D000328:Adult; D016058:Analgesia, Patient-Controlled / Q000379:methods*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage* / Q000009:adverse effects; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects; D001794:Blood Pressure / Q000187:drug effects; D020927:Dexmedetomidine / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004338:Drug Combinations; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007044:Hysterectomy; D007262:Infusions, Intravenous; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage* / Q000009:adverse effects; D010149:Postoperative Pain / Q000517:prevention & control*; D020250:Postoperative Nausea and Vomiting / Q000139:chemically induced
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D004338:Drug Combinations; D020927:Dexmedetomidine; D009020:Morphine