Propanidid and methohexitone: their comparative potency and narcotic action.

The paper presents a method of study designed to establish the narcotic potency ratio between the two agents methohexitone and propanidid. Comparisons were made through a range of five doses of each drug such that the smallest dose failed to produce narcosis in 50 per cent of subjects and the largest resulted in over 50 per cent still unresponsive after 6 minutes. By plotting curves relating dose to arousal times a reasonably accurate means of deriving a potency ratio is achieved. The results show methohexitone to be 5.2 times as potent as propanidid in all doses used. Equipotent doses of each drug produce the same duration of anaesthesia. No attempt was made to evaluate final recovery times.