hypnotic drugs, drugs that induce sleep, sometimes called soporifics. In general, hypnotics are central nervous system depressants. Alcohol, laudanum (see opium), bromide salts, and herbs such as valerian have been used as hypnotics. Barbiturates and benzodiazepines are frequently prescribed hypnotics. Smaller doses of these same drugs may be used as sedatives.

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 heparin and coumarin; various smooth-muscle relaxants such as papaverine, 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).

See also drug resistance; drug poisoning; drug addiction and drug abuse.

Sources of Drugs

Drugs are obtained from many sources. Many inorganic materials, such as metals, are chemotherapeutic; hormones, alkaloids, vaccines, and antibiotics come from living organisms; and other drugs are synthetic or semisynthetic. Synthetics are often more effective and less toxic than the naturally obtained substances and are easier to prepare in standardized units. The techniques of genetic engineering are being applied to the production of drugs, and genetically engineered livestock that incorporate human genes are being developed for the production of scarce human enzymes and other proteins (see pharming).

Pharmacopoeia and Drug Safeguards

Standards for drugs and tests for their identity, quality, and purity are given in the U.S. pharmacopoeia, first published in 1820 and at first revised every 10 years, later every 5 years. The British publish a similar pharmacopoeia. The National Formulary published by the American Pharmaceutical Association gives the composition, description, method of preparation, and dosage for drugs; the Physician's Desk Reference is a privately published compilation of information supplied by drug companies about their drug products, published yearly. The scientific study of drugs, their actions and effects, is pharmacology.

Legislation to safeguard drug purchasers began in the United States with the Pure Food and Drugs Act of 1906; this was superseded by the more inclusive and more stringent federal Food, Drug, and Cosmetic Act of 1938. Such laws are enforced by the Food and Drug Administration. The 1962 Kefauver-Harris amendments to the Food, Drug, and Cosmetic Act increased the authority of the Food and Drug Administration to regulate testing and marketing of new drugs. There are two marketing classes of drugs: ethical drugs, for which prescriptions are needed, and proprietary drugs, which are sold over the counter without prescription. Many of the latter, such as mouthwashes, gargles, and cold preparations, are only slightly, if at all, effective in curing ailments.

Common term for sulfonamide drug, any member of a class of synthetic antibacterial drugs with a particular chemical structure including both sulfur and nitrogen atoms. Their effectiveness against bacteria was discovered in 1932 by Gerhard Domagk, and they became the first chemical substances systematically used against human bacterial infections. Sulfa drugs inhibit the growth and multiplication of certain bacteria (but do not kill them) by interfering with the synthesis of folic acid. Because of their toxicity and growing bacterial resistance, sulfa drugs are no longer in common use (except for urinary-tract infections, certain forms of malaria, and preventing infection of burns), having been largely superseded by less toxic antibiotics.

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or medicinal poisoning

Harmful effects of drugs, from overdose or sensitivity to regular doses. Many medicines are dangerous; the margin between dose and overdose is often narrow. A normally safe dose may be toxic in some people, over time, or in combination with certain foods, alcohol, or other drugs. Safeguards to prevent drug poisoning include testing in animals, then human volunteers, and then patients. Drugs unsafe for self-medication are available only to doctors or by prescription. Pharmacists advise the public on proper use.

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or chemical dependency

Physical and/or psychological dependency on a psychoactive (mind-altering) substance (e.g., alcohol, narcotics, nicotine), defined as continued use despite knowing that the substance causes harm. Physical dependency results when the body builds up a tolerance to a drug, needing increasing doses to achieve the desired effects and to prevent withdrawal symptoms. Psychological dependency may have more to do with one's psychological makeup; some people may have a genetic tendency to addiction. The most common addictions are to alcohol (see alcoholism), barbiturates, tranquilizers, and amphetamines, as well as to the stimulants nicotine and caffeine. Initial treatment (detoxification) should be conducted with medical supervision. Individual and group psychotherapy are critical elements. Alcoholics Anonymous and similar support groups can increase the success rate of other efforts. The ability to admit addiction and the will to change are necessary first steps.

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Any chemical agent that affects the function of living things. Some, including antibiotics, stimulants, tranquilizers, antidepressants, analgesics, narcotics, and hormones, have generalized effects. Others, including laxatives, heart stimulants, anticoagulants, diuretics, and antihistamines, act on specific systems. Vaccines are sometimes considered drugs. Drugs may protect against attacking organisms (by killing them, stopping them from reproducing, or blocking their effects on the host), substitute for a missing or defective substance in the body, or interrupt an abnormal process. A drug must bind with receptors in or on cells and cannot work if the receptors are absent or its configuration does not fit theirs. Drugs may be given by mouth, by injection, by inhalation, rectally, or through the skin. The oldest existing catalogue of drugs is a stone tablet from ancient Babylonia (circa 1700 BC); the modern drug era began when antibiotics were discovered in 1928. Synthetic versions of natural drugs led to design of drugs based on chemical structure. Drugs must be not only effective but safe; side effects can range from minor to dangerous (see drug poisoning). Many illegal drugs also have medical uses (see cocaine; heroin; drug addiction). Seealso drug resistance; pharmacology; pharmacy.

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Synthetic version of a controlled narcotic substance. Designer drugs usually are synthesized for the first time in an attempt to create a chemical whose molecular structure differs only slightly from that of some well-known controlled substance but whose effects are essentially the same. Because of the difference in molecular structure, the designer drug, unlike the controlled substance, ordinarily will not be specifically listed as illicit by law-enforcement organizations. Many designer drugs are manufactured in clandestine laboratories, often by amateurs; for this reason they are sometimes more dangerous than the drugs they are intended to replace. One of the best-known is MDMA (3,4- methylenedioxymethamphetamine), a variation of methamphetamine, popularly called Ecstasy. Nonnarcotic synthetic chemical compounds designed to interact with specific proteins and enzymes in order to combat disease also have been called designer drugs.

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Agency of the U.S. Department of Health and Human Services. Established in 1927, it inspects, tests, approves, and sets safety standards for foods and food additives, drugs, chemicals, cosmetics, and household and medical devices. It can prevent untested products from being sold and take legal action to halt the sale of undoubtedly harmful products or of products that involve a health or safety risk. Its authority is limited to interstate commerce; it cannot control prices nor directly regulate advertising except of prescription drugs and medical devices.

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