Doses for Laboratory Animals based on Metabolic Rate

Abstract

The differences in metabolic rates (M) of different mammals often make it difficult to estimate the dose of e.g. anaesthetics from one species to another. It is well known that the mammalian metabolic rate is correlated to the body weight (W), and the relationship between body weight and metabolic rate kan be expressed using the equation:
(1) M = 3.8 x W^-25
Using the assumption, that the dose of e.g. an anaesthetic only depends on the metabolic rate of the animal, a simple mathematic equation can be used in scaling the dose from one species to another:

As an example the equation is employed for the calculation of the doses of pentobarbital for a series of different mammals of different size. The calculated doses agree well with the doses reported in the literature. The equation may be of generel usefulness for a quick calculation of a suitable dose level, when the dose level of another species is known.