Assessing liver

If no toxicity is manifested during the first year of therapy, then redraw liver enzymes every 6-12 months assess liver for cirrhosis every 1-2 years by ultrasound and every 4-6 years by CT or MRI scan biopsy as... 

Some of the information (discussed previously in Chapter 4) needed to assess liver function can be found in the patient s medical notes (e.g. laboratory results). However, it is generally useful to speak to an... 

Having assessed liver function, you need to go back to basic principles of pharmacokinetics what does the liver normally do and what types of dysfunction may affect drug handling In Chapter 5 we have incorporated the theory with practical advice that you can apply to a patient. Chapter 6 considers the impact of a drug s side-effect profile on a patient with liver dysfunction. 

Stable isotopes of retinal and (3-carotene have also been employed to assess liver vitamin A stores in healthy individuals, and the best measure of vitamin A status (Furr et ah, 1989). The relative ratio of circulating isotopically labeled retinol is later assessed to estimate liver levels (Wang et ak, 2000 Hickenbottom et ah, 2002b) and without this technique, a liver biopsy would be necessary to estimate liver levels. 

Bergquist et al. (35) presented examples in which several laboratory tests that are commonly used to assess liver function provide a more reliable indication of impaired drug metabolic clearance than does the... 

The following classification is used to assess liver injury (H. Bockhorn et al., 1982) ... 

Sorbitol may also be used analytically as a marker for assessing liver blood flow. " ... 

Several multianalyte diagnostic methods have been marketed to assess the level of liver fibrosis, such as Fibroscan and Fibrotest.39 These tests may leave room for improved biomarkers however, the accuracy of the biopsy method has also been questioned as a source of error in evaluation of these studies. Additional liver biomarkers are needed that improve on the specificity of ALT to differentially diagnose injury severity, or improve on the sensitivity of serum bilirubin or serum albumin and clotting factors to help assess liver function. 

Before administration Obtain the baseline cognitive, behavioral, and functional deficits of the patient. Assess liver and renal function. 

Gao L, Ramzan I, Baker A. Potential use of pharmacological markers to quantitatively assess liver fimc-tion during liver transplantation surgery. Anaesth Intensive Care 2000 28 375-85. 

Rossi E, Adams L, Prins A, Bulsara M, de Boer B, Garas G, et al. Validation of the FibroTest biochemical markers score in assessing liver fibrosis in hepatitis C patients. Chn Chem 2003 49 450-4. 

Most investigators who have used indocyanine green to assess liver function have measured its FDR or PDR (C16,1128, M17). Some values for FDR in normals are listed in Table 4. 

The standard battery of biochemical tests used to assess liver function usually includes the measurement of the activity in plasma of one of the aminotransferases [either aspartate aminotransferase (AST) or alanine aminotransferase (ALT)]. Such measurements are performed to assess the integrity of the hepatocyte membrane. The measurement of AST provides poor organ specificity due to the ubiquitous nature of the enzyme and both ALT and AST are relatively poor at detecting damage that is occurring to the centrilobular hepatocytes. The inadequacy of the aminotransferases at detecting centrilobular liver damage may be... 

The alterations of blood pyruvate levels are of limited value in assessing liver dysfunction, since they are not of regular occurrence, are nonspecific (PI), and do not always follow the clinical symptoms (S38). 

Although most endpoints are amenable to a hormesis evaluation, some commonly assessed endpoints are inherently problematic. For example, serum enzyme activities such as those routinely taken to assess liver toxicity, such as ALT and AST, would not be a means to study hormesis because any changes from normal, whether high or low, may be indicative of some underlying pathology. In order to assess whether liver changes would be reflective of a hormetic response it may be necessary to utilize an animal model with a high predisposition to liver disease or to create experimental conditions that would promote the early onset of liver disease. 

A test that can be used to assess liver function when other liver function tests are normal. It is a test of the ability of the liver to conjugate and excrete the dye bromsulphthalein (BSP). It consists of an intravenous injection of the dye followed by the collection of blood specimens up to 45 minutes after the injection. Bromsulphthalein is then measured in the serum samples by adding alkali which renders the dye purple. In normal subjects less than 5% of the dose should remain in the circulation after 45 minutes. Increased retention of BSP is a sensitive index of hepatic dysfunction although false positives may occur if there is impaired circulation in the liver. 

Aminotransferases are intracellular eniymes, present in both cytosolic and mitochondrial locations. Any damage to tissue can be assessed by the leakage of these enzymes from cells, and therefore theh presence in the plasma. ALT and AST are particularly useful in assessing liver disease and myocardial infarction. 

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