Anesthesiology
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Previous data indicate that morphine-6beta-glucuronide (M6G), a morphine metabolite with analgesic properties, can paradoxically increase pain sensitivity in mice and humans. The authors tested mice and humans for M6G hyperalgesia and assessed the contribution of N-methyl-D-aspartate receptor activity in mice. ⋯ These data indicate that M6G causes hyperalgesia independent of previous or concurrent opioid receptor activity or analgesia. In mice, a causal role for the N-methyl-D-aspartate receptor is also indicated.
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The use of fentanyl as a potent analgesic is contradicted by marked respiratory depression among a subpopulation of patients. The commonly used approach of reversing fentanyl-induced respiratory depression with mu-opiate receptor antagonists such as naloxone has the undesirable effect of blocking analgesia. Here, the authors report a clinically feasible pharmacological solution for countering fentanyl-induced respiratory depression via a mechanism that does not interfere with analgesia. Specifically, to determine if the ampakine CX717, which has been proven metabolically stable and safe for human use, can prevent and rescue from severe fentanyl-induced apnea. ⋯ CX717 is an agent that enhances the safety of using opiate drugs while preserving the analgesic effects. This advancement could significantly improve pain management in a variety of clinical settings.