Measuring altered disposition of xenobiotics in experimental models of liver disease.

Understanding the metabolic pathway and excretion mechanisms governing the disposition of a compound is essential to the safe use of pharmaceutical agents. Because the liver is the primary organ responsible for the metabolism and elimination of xenobiotics, chronic liver disease can have a significant effect on the disposition of many xenobiotics due to changes in the expression or function of drug metabolizing enzymes and transporters. Liver disease can result in increased retention of a xenobiotic within the body, causing greater exposure of the individual to a potentially harmful compound, which may lead to toxicity. On the other hand, liver disease may also up-regulate the elimination processes of a xenobiotic, accelerating its removal from the body. With regard to a pharmaceutical agent, enhanced elimination may result in a decreased pharmacologic effect. Such alterations may necessitate dosage adjustments to achieve the desired therapeutic outcome.