Human Drug Metabolism, An Introduction, Second Editionprovides an accessible introduction to the subject and will beparticularly invaluable to those who already have someunderstanding of the life sciences. Completely revised and updatedthroughout, the new edition focuses only on essential chemicaldetail and includes patient case histories to illustrate theclinical consequences of changes in drug metabolism and its impacton patient welfare. After underlining the relationship between efficacy, toxicityand drug concentration, the book then considers how metabolizingsystems operate and how they impact upon drug concentration, bothunder drug pressure and during inhibition. Factors affecting drugmetabolism, such as genetic polymorphisms, age and diet arediscussed and how metabolism can lead to toxicity is explained. Thebook concludes with the role of drug metabolism in the commercialdevelopment of therapeutic agents as well as the pharmacology ofsome illicit drugs.
Preface. Preface to First Edition. 1. Introduction. 1.1 Therapeutic window. 1.2 Consequences of drug concentration changes. 1.3 Clearance. 1.4 Hepatic extraction and intrinsic clearance. 1.5 First pass and plasma drug levels. 1.6 Drug and xenobiotic metabolism. 2. Drug Biotransformational Systems Origins andAims. 2.1 Biotransforming enzymes. 2.2 Threat of lipophilic hydrocarbons. 2.3 Cell communication. 2.4 Potential food toxins. 2.5 Sites of biotransforming enzymes. 2.6 Biotransformation and xenobiotic cell entry. 3. How Oxidative Systems Metabolize Substrates. 3.1 Introduction. 3.2 Capture of lipophilic molecules. 3.3 Cytochrome P450s classification and basic structure. 3.4 CYPs main and associated structures. 3.5 Human CYP families and their regulation. 3.6 Main human CYP families. 3.7 Cytochrome P450 catalytic cycle. 3.8 Flavin monooxygenases (FMOs). 3.9 How CYP isoforms operate in vivo. 3.10 Aromatic ring hydroxylation. 3.11 Alkyl oxidations. 3.12 Rearrangement reactions. 3.13 Other oxidation processes. 3.14 Control of CYP metabolic function. 4. Induction of Cytochrome P450 Systems. 4.1 Introduction. 4.2 Causes of accelerated clearance. 4.3 Enzyme induction. 4.4 Mechanisms of enzyme induction. 4.5 Induction general clinical aspects. 5. Cytochome P450 Inhibition. 5.1 Introduction. 5.2 Inhibition of metabolism general aspects. 5.3 Mechanisms of inhibition. 5.4 Cell transport systems and inhibition. 5.5 Major clinical consequences of inhibition of drugclearance. 5.6 Use of inhibitors for positive clinical intervention. 5.7 Summary. 6. Conjugation and Transport Processes. 6.1 Introduction. 6.2 Glucuronidation. 6.3 Sulphonation. 6.4 The GSH system. 6.5 Glutahione S-transferases. 6.6 Epoxide hydrolases. 6.7 Acetylation. 6.8 Methylation. 6.9 Esterases/amidases. 6.10 Amino acid conjugation (glycine or glutamate). 6.11 Phase III transport processes. 6.12 Biotransformation-integration of processes. 7. Factors Affecting Drug Metabolism. 7.1 Introduction. 7.2 Genetic polymorphisms. 7.3 Effects of age on drug metabolism. 7.4 Effects of diet on drug metabolism. 7.5 Gender effects. 7.6 Smoking. 7.7 Effects of ethanol on drug metabolism. 7.8 Artificial livers. 7.9 Effects of diseases on drug metabolism. 9.10 Summary. 8. Role of Metabolism in Drug Toxicity. 8.1 Adverse drug reactions: definitions. 8.2 Reversible drug adverse effects: Type A. 8.3 Irreversible drug toxicity: Type B. 8.4 Type B1 necrotic reactions. 8.5 Type B2 reactions: immunotoxicity. 8.6 Type B3 reactions: role of metabolism in cancer. 8.7 Summary of biotransformational toxicity. Appendix A: Methods in Drug Metabolism. A.1 Introduction. A.2 Analytical techniques. A.3 Human liver microsomes. A.4 Human hepatocytes. A.5 Human cell lines. A.6 Heterologous recombinant systems. A.7 Animal model developments in drug metabolism. A.8 Toxicological metabolism-based assays. A.9 In silico studies. A.10 Summary. Appendix B. Metabolism of Major Illicit Drugs. B.1 Introduction. B.2 Opiates. B.3 Cocaine. B.4 Hallucinogens. B.5 Amphetamines. B.6 Cannabis. B.7 Dissociative anaesthetics. Appendix C. Examination Techniques. C.1 Introduction. C.2 A first-class answer. C.3 Preparation. C.4 The day of reckoning. Appendix D. Summary of Major CYP Isoforms and theirSubstates, Inhibitors and Inducers. Suggested Further Reading. Index.