• DOI:10.1097/00000539-200006000-00018
• Corpus ID: 32240231

14-Methoxymetopon, A Potent Opioid, Induces No Respiratory Depression, Less Sedation, and Less Bradycardia than Sufentanil in the Dog

@article{Freye200014MethoxymetoponAP,
  title={14-Methoxymetopon, A Potent Opioid, Induces No Respiratory Depression, Less Sedation, and Less Bradycardia than Sufentanil in the Dog},
  author={Enno Christian Kurt Freye and Helmut Schmidhammer and Leo Latasch},
  journal={Anesthesia \& Analgesia},
  year={2000},
  volume={90},
  pages={1359–1364}
}

• E. Freye, H. Schmidhammer, L. Latasch
• Published 1 June 2000
• Medicine
• Anesthesia & Analgesia

Opioids of the &mgr;-receptor type depress respiration and induce addiction. At 10-min intervals 14-methoxymetopon (HS-198), which is 20,000 times more potent than morphine in the acethylcholine-writhing test, was given in graded IV doses (3, 6, and 12 &mgr;g/kg) to awake, trained canines (n = 7). The following variables were derived: Pao2, Paco2, heart rate (lead II of the electrocardiogram), mean arterial blood pressure, relative changes in the &dgr; domain and the &bgr; domain of the electroencephalogram, the somatosensory evoked potential, and the skin-twitch reflex to electrical stimuli. Thereafter, 20 &mgr;g/kg naltrexone was given for reversal. After a washout period, the same animals were exposed to similar doses of sufentanil (SUF) followed by naltrexone. Both opioids induced a dose-related bradycardia and hypotension. The maximal bradycardic effect was 19% after HS-198 and 42% after SUF (P < 0.005). The maximal hypotension was 6% after HS-198 and 20% after SUF (P < 0.01). In the electroencephalogram, power in the &dgr; band increased by 288% after HS-198 and by 439% after SUF (P < 0.01); simultaneously, power in the &bgr; band decreased by 71% and by 95.7%, respectively (P < 0.01). Pao2 decreased by 41% after SUF and by 4% after HS-198, and Paco2 increased by 56.8% and 6.6% in SUF and HS-198, respectively (P < 0.001). Both opioids induced a dose-related depression in the somatosensory evoked potential and increased tolerance to skin-twitch. The maximal effect was 92.7% after SUF and 81.3% after HS-198 was not significant. Naltrexone reversed all changes back to control. Compared with SUF, HS-198 does not induce hypoxia and hypercarbia, induces less hypotension and bradycardia, and induces less sedative effects. Implications Compared with sufentanil, 14-methoxymetopone does not induce hypoxia and hypercarbia, induces less hypotension and bradycardia, and induces less sedative effects (electroencephalogram). Antinociception is similar to sufentanil (skin-twitch method, amplitude depression in the evoked potential). All effects are reversed by naltrexone. Interaction of &kgr;-receptor is suggested.