PHARMACOLOGY IN THE 20TH AND 21 ST CENTURIES

Beginning in the 20th century, the fresh wind of synthetic chemistry began to revolutionise the pharmaceutical industry, and with it the science of pharmacology. New synthetic drugs, such as barbiturates and local anaesthetics, began to appear, and the era of antimicrobial chemotherapy began with the discovery by Paul Ehrlich in 1909 of arsenical compounds for treating syphilis. Further breakthroughs came when the sulfonamides, the first antibacterial drugs, were discovered by Gerhard Domagk in 1935, and with the development of penicillin by Chain and Florey during the Second World War, based on the earlier work of Fleming

ORIGINS AND ANTECEDENTS

Pharmacology can be defined as the study of the effects of drugs on the function of living systems. As a science, it was born in the mid-19th century, one of a host of new biomedical sciences based on principles of experimentation rather than dogma that came into being in that remarkable period. Long

What is Pharmacology?

WHAT IS A DRUG?

For the purposes of this book, a drug can be defined as a chemical substance of known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect.

A few points are worth noting. Drugs may be synthetic chemicals, chemicals obtained from plants or animals, or products of genetic engineering. A medicine is a chemical preparation, which usually but not necessarily contains one or more drugs, administered with the intention of producing a therapeutic effect. Medicines usually contain other substances (excipients, stabilisers, solvents, etc.) besides the active drug, to make them more convenient to use. To count as a drug, the substance must be administered as such, rather than released by physiological mechanisms. Many substances, such as insulin or thyroxine, are endogenous hormones but are also drugs when they are administered intentionally. Many drugs are not used in medicines but are nevertheless useful research tools. In everyday parlance, the word drug is often associated with addictive, narcotic or mind-altering substances-an unfortunate negative connotation that tends to bias opinion against any form of chemical therapy. In this book, we focus mainly on drugs used for therapeutic purposes but also describe important examples of drugs used as experimental tools.