Failure of thyrotropin releasing hormone to reverse fentanyl-flunitrazepam anesthesia in man.

The effect of thyrotropin releasing hormone (TRH) on modified neuroleptanesthesia with fentanyl-flunitrazepam was investigated in an open pilot study of 15 neurosurgical patients. Before and 15, 30, and 60 minutes after extubation and subsequent administration of 400 micrograms TRH, the following parameters were evaluated: PaO2, PaCO2, vigilance, and pain sensation. Although no TRH-related impairment of postoperative analgesia was observed, respiratory depression and impaired vigilance were not significantly reversed. These findings contradict a number of experimental studies using animal models which indicated that TRH, due to its centrally mediated ergotropic activity, antagonizes the narcotic effect of various CNS depressants and anesthetics.