Metabolism of enflurane in man following a second exposure.

A second administration of one half MAC enflurane for two hours one week following a previous identical exposure caused no increase in urinary inorganic Fluoride excretion (UFV). At this dosage of 1 MAC hour, which is equivalent to use as a supplement, UFV did not sub-anaesthetic doses of enflurane are administered at this time interval there appears to be no increased risk of nephrotoxicity. This study also provides strong support for the concept that drug metabolism is very reproducible within individuals but there is considerable variation between individuals. Since the subjects in this study were all of similar age, and drug free, the results are in keeping with recent twin studies which indicate that individual differences in drug metabolism are largely determined on a genetic basis.