Antagonism of Fentanyl with Naloxone during N₂O+O₂+ Halothane Anaesthesia

Abstract

To investigate the antagonistic effect of naloxone on fentanyl-induced respiratory depression, 55 patients (randomly divided into various study and control groups were studied during nitrous-oxide-oxygen-halothane anaesthesia. Respiratory depression after 0.1 mg of fentanyl was totally reversed by 10 microgram/kg of naloxone, measured as 100% restoration of spontaneous respiration, normal minute volume and end-tidal CO2, while 15 microgram/kg of naloxone was needed to antagonize 0.2 mg of fentanyl. The respective control groups remained apnoeic. If no fentanyl had previously been administered, there was no difference in the respiratory behaviour of naloxone-treated and control patients, which indicates that no unspecific analeptic effect of naloxone could be demonstrated. The circulatory changes after fentanyl were nearly reversed by naloxone, as has been found earlier with other narcotics. Recovery from anaesthesia was scored from 0 to 10 (using a modification of Apgar scores for newborns), and somewhat higher mean scores were obtained with the naloxone-treated patients than with their controls. However, higher postoperative pain scores were recorded in these patients as well as a higher incidence of nausea and vomiting. The study demonstrates the dose-relationships of fetanyl and naloxone for estimation of total antagonism; however, the use of naloxone for partial antagonism at the termination of anaesthesia cannot be based on these findings.

Plasma Fentanyl Concentrations and Clinical Observations during and after Operation

“…The respiratory depression following surgery in the patients reported by Adams and Pybus (1978) may be associated with such lack of stimulation, although the event was delayed much longer than the time at which second peaks of fentanyl were observed in the plasma in the present investigation. It is possible that the effects may have been compounded by the usual opiate premedication which was given; however, other data suggest that pethidine has no residual effects (Tigerstedt, 1977). Vejlsted, Hansen and Jacobsen (1977) found that pethidine used as premedication for patients undergoing neuroleptanaesthesia with fentanyl 420 (jtg in divided doses was associated with respiratory depression lasting up to 6 h. It is also possible that fentanyl concentrations in the central nervous system are relatively great at this time.…”

Treatment of opioid overdose: current approaches and recent advances

“…Studies in patients administered fentanyl anesthesia during surgery have reported that naloxone reversed respiratory depression (Takahashi et al 2004 ; Tigerstedt 1977 ). While these data are intriguing, it is difficult to generalize these results to illicit fentanyl overdose scenarios, which can vary widely with respect to the dose administered and specific fentanyl analog.…”