Evidence in now available to demonstrate that most inhalational anesthetics which were considered to be inert until early in 1960 are metabolised in the body. Biotransformation of the volatile anesthetics clinically used has become an area of interest to the anesthesiologist, since the problems of possible toxic effects produced by anesthetic metabolites on vital organ systems such as liver and kidney are generally concerned. This lecture was mainly divided into four sections:
a) Biotransformation system of drugs including anesthetics and factors influencing anesthetic-associated organ toxicity.
b) Metabolism of inhalational anesthetics.
c) Metabolism of narcotic analgesics.
d) Mechanism of toxic injury produced by anesthetics.
Firstly, some important key words such as biotransformation, cytochrome P450 system, enzyme induction, free radical formation, and covalent binding were explained, Secondly, the metabolism of the inhalational anesthetics such as diethyl ether, trichloroethylene, chloroform, halothane, fluroxene, methoxyflurane, enflurane, and nitrous oxide associated with new volatile anesthetics such as isoflurane and sevoflurane were reviewed. In addition, author's new data regarding the metabolism of fentanyl in man, were also demonstrated, since this narcotic is now widely used in the clinical anesthesia.
Finally, mechanism of toxic injury such as nephrotoxicity, hepatotoxicity, and bone marrow disturbances associated with anesthetics were discussed.
