Drugs substances used in medicine either externally or internally for curing, alleviating, or preventing a disease or deficiency. At the turn of the century only a few medically effective substances were widely used scientifically, among them ether , morphine , digitalis , diphtheria antitoxin, smallpox vaccine, iron , quinine , iodine , alcohol, and mercury . Since then, and particularly since World War II, many important new drugs have been developed, making chemotherapy an important part of medical practice. Such drugs include the antibiotics , which act against bacteria and fungi; quinacrine and other synthetics that act against malaria and other parasitic infections; cardiovascular drugs, including beta-blockers and ACE inhibitors ; diuretics , which increase the rate of urine flow; whole blood, plasma, and blood derivatives; anticoagulants such as heparinpapaverine , used in heart and vascular diseases; smooth-muscle stimulants; immunologic agents, which protect against many diseases and allergenic substances; hormones such as thyroxine , insulin , and estrogen and other sex hormones; psychotherapeutics such as antianxiety drugs and antidepressant drugs ; cortisone and synthetic corticosteroid drugs used in treating inflammatory diseases such as arthritis; vitamins and dietary minerals; antidotes for poisons; and various drugs that act as stimulants or depressants on all or various parts of the nervous system, including analgesics , narcotics , amphetamines , and barbiturates (see also anesthesia ; psychopharmacology ; hallucinogenic drug ). and coumarin; various smooth-muscle relaxants such as antianxiety drugs and antidepressant drugs ; cortisone and synthetic corticosteroid drugs used in treating inflammatory diseases such as arthritis; vitamins and dietary minerals; antidotes for poisons; and various drugs that act as stimulants or depressants on all or various parts of the nervous system, including analgesics , narcotics , amphetamines , and barbiturates (see also anesthesia ; psychopharmacology ; hallucinogenic drug ).(http://www.encyclopedia.com/topic/drugs.aspx)
