A drug can be defined as a chemical substance of known structure, other than a nutrient or as essential dietary ingredient, which when administered to a living organism, produces a biological effect.
Drugs may be synthetic 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 therapeutic effect. Medicines usually contains 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 are administered intentionally. Many drugs are not used in medicines but are neverthless useful research tools. In everyday parlence, the word drug is often associated with addictive, narcotic or mind-altering substances - an unfortunate negative connotation that tends to bias uninformed opinion against any form of chemical therapy. Even poisons fall strictly within the definition of drugs.
No comments:
Post a Comment