Medical Pharmacology and Therapeutics E-Book

Derek G. Waller, Anthony Sampson

• Publisher: Elsevier
• Year: 2017
• eBook ISBN: 9780702071904
• Edition: 5
• Topic: Medicina
• Subtopic: Farmacología

Medical Pharmacology & Therapeutics, now in its fifth edition, offers medical students all they need to know to become safe and effective prescribers. It forms a complete, integrated resource for basic pharmaceutical science, pathophysiology, clinical pharmacology, and therapeutics.

The fifth edition has been extensively revised and updated throughout. Key features include:

• Clear, disease-based approach.

• Presentation of how drugs are used in clinical practice.

• Succinct explanations of the major pathogenic mechanisms of each disease and consequent clinical signs and symptoms.

• Comprehensive reviews of major drug classes relevant to each disease.

• Structured approach to the principles of disease management – outlining core principles of drug choice and planning a therapeutic regimen for common diseases.

• Quick-reference drug compendia illustrating key similarities and differences among all BNF-listed drugs in each class.

• Comes with free e-book on StudentConsult.

• New sections on key and evolving topics, including prescribing safety and pharmacovigilance.

• Updated figures to further clarify complex areas.

• Revised multiple-choice and case-based questions for self-assessment.

Section 1

General Principles

Outline

1 Principles of pharmacology and mechanisms of drug action

2 Pharmacokinetics

3 Drug discovery, safety and efficacy

4 Neurotransmission and the peripheral autonomic nervous system

1

Principles of pharmacology and mechanisms of drug action

Studying pharmacology 3

Finding drug information 4

Receptors and receptor-mediated mechanisms 4

Actions of drugs at binding sites (receptors) 4

Major types of receptors 5

Other sites of drug action 12

Properties of receptors 13

Properties of drug action 15

Dose–response relationships 16

Types of drug action 17

Agonists 17

Antagonists 18

Partial agonists 18

Inverse agonists 18

Allosteric modulators 19

Enzyme inhibitors and activators 19

Nonspecific actions 19

Physiological antagonists 19

Tolerance to drug effects 19

Genetic variation in drug responses 20

Summary 21

Self-assessment 21

Answers 22

Further reading 22

Appendix: student formulary 28

Studying Pharmacology

Drugs are defined as active substances administered to prevent, diagnose or treat disease, to alleviate pain and suffering, or to extend life. Pharmacology is the study of the effects of drugs on biological systems, with medical (or clinical) pharmacology concerned with the drugs that doctors, and some other healthcare professionals, prescribe for their patients. The prescribing of drugs has a central role in therapeutics, and gaining a good knowledge of pharmacology is essential for health professionals to become safe and effective prescribers.

Drugs may be chemically synthesised or purified from natural sources with or without further modification, but their development and clinical use are based on rational evidence of efficacy and safety derived from controlled experiments and randomised clinical trials. Drugs can be contrasted with placebos (placebo is Latin for ‘I will please’), defined as inactive substances administered as though they are drugs, but which have no therapeutic effects other than potentially pleasing the patient, providing a sense of security and progress. Pharmacology evolved on the principle of studying known quantities of purified, active substances to identify their specific mechanisms of action and to quantify their effects in a reproducible manner, usually compared with a placebo or other control substance.

Much of the success of modern medicine is based on pharmacological science and its contribution to the development of safe and effective pharmaceuticals. This book is confined to pharmacology as it relates to human medicine and aims to develop knowledge and understanding of medical pharmacology and its application to therapeutics. The objectives of learning about medical pharmacology and therapeutics are:

▪ to understand the ways that drugs work to affect human systems, as a basis for safe and effective prescribing;

▪ to appreciate that pharmacology must be understood in parallel with related biological and clinical sciences, including biochemistry, physiology and pathology;

▪ to develop numerical skills for calculating drug doses and dilutions, and to enable accurate comparison of the relative benefits and risks of different drugs;

▪ to comprehend and participate in pharmacological research advancing the better treatment of patients.

The answer to the frequently asked question ‘What do I need to know?’ will depend upon the individual requirements of the programme of study being undertaken and the examinations that will be taken. The depth and type of knowledge required in different areas and topics will vary when progressing through the programme; for example, early in the course it may be important to know whether a drug has a narrow safety margin between its wanted and unwanted effects, and in the later years this may translate into detailed knowledge of how the drug's effects are monitored in clinical use. Personal enthusiasm for medical pharmacology is important and should be driven by the recognition that prescribing medicines is the most common intervention doctors (and increasingly other health professionals) use to improve the health of their patients.

Finding Drug Information

Learning about medical pharmacology is best approached using a variety of resources in a range of learning scenarios and preferably in the context of basic science and therapeutics, not from memorising lists of drug names. The following provides a useful structure to organise the types of information that you should aim to encounter:

▪ the nonproprietary (generic) drug name (not the proprietary or trade name);

▪ the class or group to which the drug belongs;

▪ the way the drug works (its mechanism of action and its clinical effects), usually shared to variable extents by other drugs in the same class;

▪ the main clinical reasons for using the drug (its indications);

▪ any reasons why the drug should not be used in a particular situation (its contraindications);

▪ whether the drug is a prescription-only medicine (PoM) or is available without prescription (over-the-counter [OTC]);

▪ how the drug is given (routes of administration);

▪ how its effects are quantified and its doses modified if necessary (drug monitoring);

▪ how the drug is absorbed, distributed, metabolised and excreted (ADME; its pharmacokinetics), particularly where these show unusual characteristics;

▪ the drug's unwanted effects, including any interacti...

Table of contents

• Cover image
• Title Page
• Table of Contents
• Dedication
• Copyright
• Preface
• Drug dosage and nomenclature
• Section 1 General Principles
• Section 2 The Cardiovascular System
• Section 3 The Respiratory System
• Section 4 The Renal System
• Section 5 The Nervous System
• Section 6 The Musculoskeletal System
• Section 7 The Gastrointestinal System
• Section 8 The Immune System
• Section 9 The Endocrine System and Metabolism
• Section 10 The Skin and Eyes
• Section 11 Chemotherapy
• Section 12 General Features: Drug Toxicity and Prescribing
• Index