[Pharmacotherapy in severe liver failure].

In severe liver failure pharmacokinetics and pharmacodynamics of different drugs are changed as compared to normals. The disturbances observed may be due to hepatic or extrahepatic mechanism, which allows a rough classification of the different drugs. The hepatic clearance of a drug is dependent upon blood perfusion of the liver (flow limited elimination) or upon the metabolic capacity of the liver (capacity limited elimination). Extrahepatic factors are protein binding and changes of the distribution volumes. Adjustment of the initial and chronic doses of any drug should depend primarily upon the pharmacokinetic profile of the drug and secondarily upon the clinical effects. Repeated measurements of drug levels can only be done in special hospitals and in patients severely in danger. Classification of drugs into groups with high, medium or low therapeutic risk may help, when a treatment plan is drawn up and may economize control of the patient.