The analgesic effect of halothane.

The effect of halothane on experimental ischaemic muscle pain has been studied in 18 human volunteers. The submaxiTniim effort tourniquet test was used in this investigation because it has been shown by previous workers to be a sensitive experimental test of analgesia. Two concentrations of halothane (0.25 and 0.35%) were compared with nitrous oxide (30%) in a controlled experiment. It was found that halothane 0.35% is of the same order of effectiveness as an analgesic as is nitrous oxide 30%. Halothane 0.25% appeared to have no analgesic action, and the possibility of a slight antanalgesic action at this concentration could not be eliminated. The practical effects of this finding are reviewed, and it is suggested that this finding taken with the work of other investigators indicates that halothane should be considered as an analgesic drug, and that the application of the term antanalgesic to this agent is misleading.