Because most drug metabolism occurs in the liver, it stands to reason that liver damage or disease will have the greatest impact on drug metabolism. Liver disease results in decreased hepatic blood flow and decreased first pass metabolism. This leads to high concentrations of parent drug in the bloodstream. It also makes the liver prone to further damage by drug toxicity. Modification of drug doses in patients with liver disease is very challenging to their physicians and pharmacists.
Conjugative processes are affected less than CYP metabolism in liver disease.
