GABAmimetics diminish antinociception of meperidine under conditions which enhance other opioid mu-agonists.

This report shows that both GABA-agonists reduced the antinociceptive potency of meperidine in both animal models under conditions which enhanced fentanyl, morphine, and the meperidine congener alphaprodine. Experimental results suggest that this effect may be due to anticholinergic properties of meperidine. Also, the duration of action of meperidine in rabbits was significantly reduced by the two GABA-agonists while the duration of fentanyl was enhanced. Since diazepam is frequently administered in combination with meperidine to achieve sedation, analgesia and amnesia in patients undergoing minor surgical procedures, these findings may have