Measurement of the Potencies of Drug Mixtures
P. S. Hewlett · Biometrics · 1969
SUMMARY Although mathematical models for joint drug action have been proposed, no satisfactory method has up to now been developed for the general measurement of potencies of mixtures of drugs. In this paper a ratio, named the joint action ratio is proposed for such measurement. This ratio is comparable in simplicity with a relative potency, and can be obtained when the drugs show potentiation, synergism, or antagonism, though not in the rare cases when their action is coalitive. For potentiation and synergism, the joint action ratio is the maximum ratio of the actual potency of the mixed drugs to what their potency would be if their action was additive; for antagonism it is the corresponding minimum ratio. The relationships between the joint action ratio and parameters in mathematical models of joint action are considered. Examples of joint action ratios and their estimation are given.