ABSTRACT
The interaction between a drug and the living organism in which the body brings about a chemical change in the drug molecule is variously referred to as detoxification, drug metabolism or biotransformation. The term detoxification has historical significance; the first foreign agents shown to be chemically altered by the body were indeed converted into substances of less potential toxicity. This term has been largely discarded since it is now apparent that the chemical reactions of the body can at times yield compounds of greater toxicity than the parent drugs. The term metabolism, as it was originally used, designated the process by which food, on the one hand, is built into living matter (anabolism) and living matter, on the other, is broken down into simple products within a cell or organism (catabolism). Metabolism is the sum of the chemical changes in living cells by which energy is provided for vital processes and activities and new materials are produced and assimilated for growth and maintenance. The chemical reactions that drugs undergo in the body do not ordinarily provide such energy or new materials. Thus the term biotransformation is preferable to drug metabolism for describing the chemical aspects of the fate of foreign compounds which are not normally considered under carbohydrate, protein, fat, vitamin, hormone or mineral metabolism.
