Enzyme induction in man: a study of the inducible systems of drug elimination.

The individual enzyme inducibility was studied with methods of menthol loading and sulphobromophthalein in groups of patients with low and average metabolism. Both methods are suitable for testing inducible conjugation systems by providing indirect information on the rate of drug elimination. In the low-metabolism groups the response in per cent correlated inversely with the initial value, and the changes were significant not only in the low but also in the average-metabolism group at the end of 30 days of phenobarbital treatment. The results are discussed with regard to the avoidability of undesired drug effects.