the word drugs to refer to medicines – substances that can cure or arrest disease, relieve symptoms, ease pain, and provide other benefits.
This definition includes essential vitamins and minerals that may be given to correct deficiency diseases.
Powerful drugs often have marked adverse effects. Drugs with less potential to cause harm are sold over the counter in pharmacies and supermarkets.
Virtually all the drugs in current use have been developed in the laboratory and are manufactured through various chemical processes. About a quarter of these are derived from plants or other organisms.
Most drugs are synthetic chemical copies, but some are still extracted from natural sources. For example, the opioid drugs, including morphine, are made from a species of poppy. Many antibiotics and some anticancer drugs are still of natural origin. The main difference between drugs of plant origin and “herbal medicines” is that drugs have been thoroughly tested to prove that they work and are safe.
Some drugs can now be made through genetic engineering, in which the genes (which control a cell’s function) of certain microorganisms are altered, changing the products of cell activity to the desired drug. For example, the hormone insulin can now be manufactured by genetically engineered bacteria. This could eliminate the need to extract insulin from animal pancreas glands, the source until recently, benefiting those people who experience adverse reactions to material derived from animal sources.
Purely synthetic drugs are either modifications of naturally occurring ones, with the aim of increasing effectiveness or safety, or drugs developed after scientific investigation of a disease process with the intention of changing it biochemically.
All drugs in general use rely on three terms: the generic, brand, and chemical names. The generic name, which is the official medical name for the basic active substance
Drugs may be grouped according to chemical similarity, for example, the benzodiazepines. More often, though, drugs are classified according to use (antihypertensive) or biological effect (diuretic).
Most drugs fit into one group, although many have multiple uses and are listed in several categories.