What is Pharmacology?

Pharmacology (Gr. pharmakon, drug; logy, discourse, study)

Pharmacology is the study of drugs - what they are, how they work and what they do. It includes the study of the manner in which the function of living tissues and organisms is modified by chemical substances and the study of the effect of chemical agents on living processes.

Pharmacology is commonly subdivided into pharmacodynamics (the biological effects of drugs) and pharmacokinetics (absorption, distribution, metabolism and excretion), also expressed as, respectively, the effects of drugs on the body and the effect of the body on drugs. (from A Dictionary of Pharmacology and Clinical Drug Evaluation, by Desmond Lawrence and John Carpenter).

Pharmacology should not be confused with Pharmacy, which is a quite different area of study involving the scientific legal and managerial aspects of dispensing medicines. It is important to realise the difference between pharmacology and pharmacy because these subjects lead to quite different careers.

To many, the word 'drug' suggests a dangerous substance to which young people become ruinously addicted. To a pharmacologist, however, the word 'drug' really means any chemical substance which changes normal body function and so includes medicines as well as poisons and drugs of abuse.

The subject is immensely broad and covers large areas of physiology, biochemistry and toxicology, all of which are concerned with the effects of chemicals on living organisms.

Three important aspects of pharmacology are:

• the use of drugs to study physiological mechanisms

• the use of drugs in medicine

• understanding the biological effects of environmental chemicals

Most of the communication systems in the body are chemical in nature. Cells (such as nerve cells, gland cells or blood cells), communicate with each other mainly by chemical substances produced and released by one particular type of cell and to which others are highly and specifically sensitive. Every cell in the body is continually responding to chemical messengers. This intricate communication system is vital for co-ordinated function and most type of drug action either mimic, augment or disrupt this communication system.

Another aspect of pharmacology is the study of the fate of drugs once they have entered the body (i.e. their absorption, distrubution, metabolism and excretion). Obviously this is crucial information for drugs destined for use in the clinic.