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Drugs

A simple and workable definition of a drug is any chemical or biologic substance that affects the body and its processes. U.S. law defines a drug as a substance intended for use in the diagnosis, cure, relief, treatment, or prevention of disease or intended to affect the structure or function of the body. (Oral contraceptives are an example of drugs that affect the function of the body rather than a disease.) This comprehensive definition of a drug, although important for legal purposes, is rather complex for everyday use.

Some people incorrectly use the word drug to mean only a substance that produces a pleasurable sensation. Drug abuse—the excessive and persistent use of mind-altering substances without medical need—has accompanied the appropriate medical use of drugs throughout recorded history. Some drugs with potential for abuse have legitimate medical purposes, and others do not.

Drugs Sections (A-Z)

Administration and Kinetics of Drugs

Drug administration is the giving of a drug by one of several means (routes). Drug kinetics (pharmacokinetics) describes how the body handles a drug and accounts for the processes of absorption, distribution, metabolism, and elimination.

Adverse Drug Reactions

Adverse drug reactions (adverse effects) are any unwanted effects of a drug.

Brand-Name and Generic Drugs

Drugs often have several names. When a drug is first discovered, it is given a chemical name, which describes the atomic or molecular structure of the drug. The chemical name is thus usually too complex and cumbersome for general use. Next, a shorthand version of the chemical name or a code name (such as RU 486) is developed for easy reference among researchers.

Drug Dynamics

Drug dynamics (pharmacodynamics) involves what a drug does to the human body.

Also of Interest

Test your knowledge

Drugs known as bioequivalents release the active ingredient into the bloodstream at virtually the same rate and in virtually the same amount as the original drug it is designed to mimic. The purpose of bioequivalence studies is to prove that: