The relative potencies of thiopentone, ketamine, propanidid, alphaxalone and diazepam. A statistical study in man

The potency of five i.v. anaesthetics (thiopentone, ketamine, alphaxalone (Althesin), propanidid and diazepam) was studied by determining the dose required to produce unconsciousness in 50% (UD50) and 95% (UD95) of patients. UD50 and UD95 were determined using the probit method. The effect of age on the anaesthetic requirement has been studied also. Relative to thiopentone, the potency was alphaxalone 9.22, diazepam 5.24, ketamine 4.37 and propanidid 1.006.