Drugs, various, effect metabolism

The hormones of adrenal glands, thyroid and pancreas exert various effects on the metabolism of drugs. Adrenalectomy of certain species e.g. rat impairs the metabolism of certain drugs, which can be reversed by administration of cortisone or prednisolone. Administration of ACTH, adrenaline or thyroxine impairs the hepatic microsomal metabolism of drugs. Thyroidectomy reduces the... 

Piperine Piperine, molecular formula C17H19NO3, a component of black pepper (Piper nigrum), has been used in various traditional medicine preparations, and also as an insecticide. Piperine has various effects on human drug metabolizing enzymes, and is marketed under the brand name, Bioperine , as an adjunct for increasing bioavailability of various dietary supplements, especially curcumin, one of the active ingredients of turmeric (Curcuma longa). 

Biochemical Functions. Ascorbic acid has various biochemical fimctions, involving, for example, coUagen synthesis, immune fimction, drug metabohsm, folate metabolism, cholesterol catabolism, iron metabolism, and carnitine biosynthesis. Clear-cut evidence for its biochemical role is available only with respect to coUagen biosynthesis (hydroxylation of prolin and lysine). In addition, ascorbic acid can act as a reducing agent and as an effective antioxidant. Ascorbic acid also interferes with nitrosamine formation by reacting directly with nitrites, and consequently may potentially reduce cancer risk. 

The dose-concentration-effect relationship is defined by the pharmacokinetic and pharmacodynamic characteristics of a drug. Pharmacokinetics comprises all processes that contribute to the time course of drug concentrations in various body fluids, generally blood or plasma, that is, all processes affecting drug absorption, distribution, metabolism, and excretion. In contrast, pharmacodynamics characterizes... 

In-vitro models can provide preliminary insights into some pharmacodynamic aspects. For example, cultured Caco 2 cell lines (derived from a human colorectal carcinoma) may be used to simulate intestinal absorption behaviour, while cultured hepatic cell lines are available for metabolic studies. However, a comprehensive understanding of the pharmacokinetic effects vfill require the use of in-vivo animal studies, where the drug levels in various tissues can be measured after different dosages and time intervals. Radioactively labelled drugs (carbon-14) may be used to facilitate detection. Animal model studies of human biopharmaceutical products may be compromised by immune responses that would not be expected when actually treating human subjects. 

A major problem facing users of the various collations of laboratory test Interferences Is the relationship between drug dosage and diagnostic test Interference and the possible synergistic effect of several drugs. The metabolic and clinical states... 

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