Enhancement of morphine analgesia by the GABAB agonist baclofen.
Opioid-GABAergic interactions for the treatment of post-operative pain were investigated in two double-blind, placebo-controlled experiments. We first studied the effect of pre-operatively administered baclofen, a GABAB receptor agonist, on the analgesia produced by intravenously administered morphine, a predominantly mu-opioid analgesic. In a separate trial, we studied the effect of baclofen on the analgesia produced by pentazocine, a predominantly kappa-opioid analgesic. While baclofen alone did not affect the level of post-operative pain, morphine analgesia was significantly enhanced by baclofen compared to placebo. In contrast, baclofen did not affect the level of pentazocine analgesia: however, females receiving pentazocine showed significantly greater analgesia than males.
Gordon
N C
NC
Department of Oral and Maxillofacial Surgery, University of California, San Francisco 94143, USA.
Gear
R W
RW
Heller
P H
PH
Paul
S
S
Miaskowski
C
C
Levine
J D
JD
D000328:Adult; D000704:Analysis of Variance; D001418:Baclofen / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D009020:Morphine / Q000627:therapeutic use*; D010149:Postoperative Pain / Q000188:drug therapy*; D010423:Pentazocine / Q000627:therapeutic use; D013997:Time Factors
D009020:Morphine; D001418:Baclofen; D010423:Pentazocine