Resumen de Drug Metabolism:: The Body's Defense against Chemical Attack
Michael S. Leonard, Andrew V. Stachulski
Most drugs, once they have performed their function, are removed from the body through a process called metabolism. This involves the chemical modification of the drug molecule by a range of enzymes present mainly in the liver. The activity of these enzymes varies considerably within the population, and these differences can be a major reason why people respond to drugs differently. Arguably the most important group of human drug metabolizing enzymes is the cytochrome P450 family. Many factors in both lifestyle and genetic makeup affect the activity of these enzymes and in turn the rate at which a drug is eliminated from the body. If this process is impaired, the level of the drug in the blood and tissues may increase, which can lead to toxic effects. Laboratory and computer models can be used to predict how new drugs are likely to be metabolized and by which enzymes, prior to their administration to humans. It is misleading to think of drug metabolism as purely a detoxifying process. Drug metabolites can also possess significant pharmacological activity, and in some cases, serious toxicity. Case studies of the metabolism of the commonly used drugs paracetamol, terfenadine, and morphine are presented to illustrate these effects.
