Download PDF Integrated Pharmacology THIRD EDITION

Sinopsis

Pharmacology is the science that deals with the actions, mechanism of action, uses, adverse effects and fate of drugs in animals and humans.

The word 'pharmacology' comes from the ancient Greek word for drug, pharmakon. It is the study of what biologically active chemical compounds (drugs) do in the body and how the body reacts to them. The word 'drug' has many meanings but is most commonly used to describe a substance used as a medicine for the treatment of disease. However, the word 'drug' may be used to refer to any biologically active compound which is taken with the intent of producing a change in the body, including:

• Familiar substances such as caffeine, nicotine and alcohol.
• Other chemicals which are abused, such as cannabis, heroin and cocaine.
• Food constituents such as vitamins, minerals and amino acids.
• Cosmetics.

Pharmacology differs from pharmacy, which is a profession that is concerned with the manufacture, preparation and dispensing of drugs. Pharmacology is concerned with the effects of drugs on living systems or their constituent components such as cells, cell membranes, cell organelles, enzymes and even DNA. As a result, the effects of drugs can be studied at many levels of biologic organization or complexity, ranging from the interaction of drugs with their target molecules in the body (usually proteins), such as enzymes, ion channels or the receptors for neurotransmitters, hormones, etc., to the effect of drugs on human populations. Pharmacologists therefore often identify themselves according to the organizational level at which they study drugs. Thus there are molecular, functional, integrative or clinical pharmacologists. A full understanding of drug action requires integrating information from each of these levels.

A knowledge of pharmacology is essential in the practice of human and veterinary medicine, where drugs are used to treat diseases of humans and animals. The principles of pharmacology also apply to toxicology, where the toxic effects of chemicals (including drugs) are studied. Whether or not a drug is used for therapy, a knowledge of itspharmacology is essential if it is to be used selectively for a defined purpose.

Ideally, all drugs would have selective actions but often they do not. A selective action can be achieved if:

• A relatively high concentration of the drug can be obtained at the target cell, tissue or organ where its action is required.
• The drug's chemical structure is such that it interacts selectively with the discrete target molecule at the location where it is to have its desired effect.

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