Comparison of morphine alone with morphine plus clonidine for postoperative patient-controlled analgesia.
BACKGROUND
Clonidine is an alpha 2 adrenergic agonist with analgesic properties. This study aimed to see if the addition of clonidine to morphine when given by patient-controlled analgesia (PCA) would improve analgesia beyond the first 12 h after surgery.


METHODS
Sixty patients undergoing lower abdominal surgery were recruited into a randomized double blind study. At the end of surgery Group C received an infusion of clonidine 4 micrograms kg-1 over 20 min, PCA clonidine 20 micrograms and morphine 1 mg bolus. Group M received an infusion of saline and then PCA morphine 1 mg bolus. Pain, sedation and nausea and vomiting were assessed after 12, 24 and 36 h, and satisfaction with analgesia was assessed at 36 h.


RESULTS
Pain scores were significantly lower in Group C between 0 and 12 h, but thereafter there was no difference. Morphine consumption was the same for both groups until 24-36 h. Nausea and vomiting was significantly reduced in Group C between 0 and 24 h. Patients in Group C were significantly happier with their pain relief (four-point scale).
Jeffs
S A
SA
University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK.
Hall
J E
JE
Morris
S
S
D000005:Abdomen / Q000601:surgery; D000328:Adult; D000368:Aged; D016058:Analgesia, Patient-Controlled / Q000379:methods*; D000700:Analgesics / Q000008:administration & dosage*; D003000:Clonidine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000628:therapy*
D000700:Analgesics; D004338:Drug Combinations; D009020:Morphine; D003000:Clonidine