Documents for "Pharmacology":

• ACE inhibitor or angiotensin-converting enzyme inhibitor , drug used to reduce elevated blood pressure (see hypertension ), to treat congestive heart failure , and to alleviate strain on hearts damaged as a result of a heart attack (see infarction ). ACE inhibitors block production of an enzyme that helps convert the protein angiotensin 1 into angiotensin 2, a protein that makes blood vessels constrict and promotes retention of fluid, raising...

• acetaminophen an analgesic and fever-reducing medicine similar in effect to aspirin. It is an active ingredient in many over-the-counter medicines, including Tylenol and Midol. Introduced in the early 1900s, acetaminophen is a coal tar derivative that acts by interfering with the...

• actinomycin any one of a group of antibiotics produced by bacteria of the genus Streptomyces. Actinomycin was the first antibiotic reported to be able to halt cancer; however, it is not widely used to treat cancers because it is highly toxic to humans, interfering with the genetic material...

• amobarbital drug that acts as a nervous system depressant. See barbiturate.

• amphetamine any one of a group of drugs that are powerful central nervous system stimulants. Amphetamines have stimulating effects opposite to the effects of depressants such as alcohol, narcotics , and barbiturates. They raise the blood pressure by causing the body to release epinephrine , postpone the need for sleep, and can reverse, partially and temporarily, the effects of fatigue. Amphetamines enhance mental alertness and the ability to concentrate, and also cause wakefulness,...

• amphotericin B antibiotic that halts the growth of several disease-causing fungi. Discovered in 1956, it is produced by bacteria of the genus Streptomyces. It is used in lotion or ointment form to treat fungal infections of the skin and is given internally only to patients with potentially fatal fungal infections. Amphotericin B is not effective...

• ampicillin a penicillin -type antibiotic that is effective against both gram-negative microorganisms and gram-positive microorganisms such as Escherichia coli. It is often used in the treatment of urinary...

• anabolic steroid or androgenic steroid , any of a group of synthetic derivatives of testosterone that promote muscle and bone growth. Used to treat uncontrolled weight loss in wasting diseases, anabolic steroids have also been taken by bodybuilders and athletes seeking increased muscle mass,...

• analgesic any of a diverse group of drugs used to relieve pain. Analgesic drugs include the nonsteroidal anti-inflammatory drugs (NSAIDs) such as the salicylates , narcotic drugs such as morphine , and synthetic drugs with morphinelike action such as meperidine (Demerol) and propoxyphene (Darvon). Aspirin and other NSAIDs (e.g., acetaminophen , ibuprofen , and naproxen ) reduce fever and inflammation as well as relieve pain. Narcotic analgesics and the morphinelike synthetic drugs depress the central nervous system and alter the perception of pain. They are used...

• angiotensin-converting enzyme inhibitor see ACE inhibitor.

• angiotensin-receptor blocker see under ACE inhibitor.

• Antabuse trade name for the drug tetraethylthiuram disulfide, used in the treatment of alcoholism. Also called sulfiram, Antabuse is nontoxic, but it alters the metabolism of alcohol in the body, making it impossible for one who is taking the drug to drink without experiencing severe...

• antacid any one of several basic substances that counteract stomach acidity (see stomach ). Antacids are used by physicians to treat hyperchlorhydria, i.e., the excessive production of hydrochloric acid by the parietal cells lining the stomach. Commonly used antacid preparations, most...

• antianxiety drug drug administered for the relief of anxiety. Although their action is not fully understood, most antianxiety medications appear to affect the action of neurotransmitters in the brain (see serotonin...

• antibiotic any of a variety of substances, usually obtained from microorganisms, that inhibit the growth of or destroy certain other microorganisms.

• anticoagulant any of several substances that inhibit blood clot formation (see blood clotting ). Some anticoagulants, such as the coumarin derivatives bishydroxycoumarin (Dicumarol) and warfarin (Coumadin) inhibit synthesis of prothrombin, a clot-forming substance, and other clotting...

• antidepressant any of a wide range of drugs used to treat psychic depression. They are given to elevate mood, counter suicidal thoughts, and increase the effectiveness of psychotherapy. Before the introduction of such drugs in the late 1950s, most patients with major depression had no recourse but hospitalization; only 45% improved after one year. In contrast, 80%-90% of such...

• antidiabetic drug any of several drugs that control blood sugar level in the treatment of diabetes. See insulin.

• antisense DNA or RNA manipulated in a laboratory so that its components (nucleotides) form a complementary copy of normal, or "sense," messenger RNA (mRNA; see nucleic acid ). Antisense techniques are used to deactivate disease-causing or undesirable genes so that they cannot produce harmful or unwanted proteins. (Conventional drugs bind directly with disease-causing...

• antiseptic agent that kills or inhibits the growth of microorganisms on the external surfaces of the body. Antiseptics should generally be distinguished from drugs such as antibiotics that destroy...

• antiviral drug any of several drugs used to treat viral infections. The drugs act by interfering with a virus's ability to enter a host cell and replicate itself with the host cell's DNA. Some drugs block the...

• aspirin acetyl derivative of salicylic acid (see salicylate ) that is used to lower fever, relieve pain, reduce inflammation, and thin the blood. Common conditions treated with aspirin include headache, muscle and joint pain, and the inflammation caused by...

• astringent substance that shrinks body tissues. Astringent medicines cause shrinkage of mucous membranes or exposed tissues and are often used internally to check discharge of serum or mucous secretions in...

• atropine alkaloid drug derived from belladonna and other plants of the family Solanaceae (nightshade family). Available either as the tincture or extract of belladonna, or as the pure substance atropine sulfate, it is a depressant of the parasympathetic nervous system. It has some chemical similarity to the body substance acetylcholine and interferes with nerve impulses transmitted by that substance. Atropine produces rapid heart rate, dilated pupils, dry skin, and anesthetizes the nerve endings in the skin. Because it relaxes...

• azidothymidine see AZT.

• AZT or zidovudine , drug used to treat patients infected with the human immunodeficiency virus ( HIV ), which causes AIDS ; also called azidothymidine. Originally developed in 1964 as an anticancer drug, AZT was never approved for that purpose. In 1984, Burroughs-Wellcome Company, which owned the rights to the drug,...

• bacitracin antibiotic produced by a strain of the bacterial species Bacillus subtilis. It is widely used for topical therapy such as for skin and eye infections; it is effective against gram-positive bacteria,...

• barbiturate any one of a group of drugs that act as depressants on the central nervous system. High doses depress both nerve and muscle activity and inhibit oxygen consumption in the tissues. In low doses barbiturates act as sedatives , i.e., they have a tranquilizing effect; increased doses have a hypnotic or sleep-inducing effect; still larger doses have anticonvulsant and anesthetic activity. The mechanism of action on the...

• belladonna or deadly nightshade, poisonous perennial plant, Atropa belladona, of the nightshade family. Native to Europe and now grown in the United States, the plant has reddish, bell-shaped flowers and shiny black berries. Extracts of its leaves and fleshy roots act to dilate the pupils of...

• benzodiazepine any of a class of drugs prescribed for their tranquilizing, antianxiety, sedative, and muscle-relaxing effects. Benzodiazepines are also prescribed for epilepsy and alcohol withdrawal. Introduced...

• beta-blocker or beta-adrenergic blocking agent , drug that reduces the symptoms connected with hypertension , cardiac arrhythmias , angina pectoris , migraine headaches, and other disorders related to the sympathetic nervous system. Beta-blockers also are sometimes given after heart attacks to stabilize the heartbeat. Within the sympathetic nervous system, beta-adrenergic receptors are located mainly in the heart, lungs,...

• brucine alkaloid similar to strychnine. See nux vomica.

• caffeine odorless, slightly bitter alkaloid found in coffee , tea , kola nuts (see cola ), ilex plants (the source of the Latin American drink maté ), and, in small amounts, in cocoa (see cacao ). It can also be prepared synthetically from uric acid. While relatively harmless, it is the most commonly used mind-altering drug in the world. When used in moderation, caffeine acts as a mild stimulant to the nervous system, blocking the neurotransmitter adenosine and resulting in a feeling of well-being and alertness. It increases the heart rate, blood pressure, and urination and stimulates...

• calcium-channel blocker any of a class of drugs used in treating hypertension , angina pectoris , and certain arrhythmias. They prevent the calcium ions needed for muscle contraction from entering the cells of smooth and cardiac muscle. This causes blood vessel walls to relax and blood to flow more freely to the...

• catecholamine any of several compounds occurring naturally in the body that serve as hormones or as neutrotransmitters in the sympathetic nervous system. The catecholamines include such compounds as epinephrine , or adrenaline, norepinephrine, and dopamine. They resemble one another chemically in having an aromatic portion (catechol) to which is attached an amine, or nitrogen-containing group. Epinephrine...

• cathartic see laxative.

• cephalosporin any of a group of more than 20 antibiotics derived from species of fungi of the genus Cephalosporium and closely related chemically to penicillin. Cephalosporins, e.g., cefaclor (Ceclor), act against both gram-positive and gram-negative bacteria (see Gram's stain ) by inhibiting bacterial cell wall synthesis. They are widely used to treat gonorrhea, meningitis, and staphylococcal and streptococcal infections in patients who cannot use penicillin. Overuse of...

• chemotherapy treatment of disease with chemicals or drugs. One chemotherapeutic approach is the development of selectively toxic substances, i.e., substances that can destroy or inhibit infecting organisms or, as in cancer, malignant tissue, but do not...

• chloral hydrate central nervous system depressant that is widely used as a hypnotic, or sleep-inducing drug. Chloral hydrate is the common ingredient, along with alcohol, in what are popularly known as knockout drops or Mickey Finns; the...

• chloramphenicol antibiotic effective against a wide range of gram-negative and gram-positive bacteria (see Gram's stain ). It was originally isolated from a species of Streptomyces bacteria. Chloramphenicol's antibiotic activity results from its interference with protein synthesis in invading microbes. However, it is a very toxic substance, its most serious and potentially...

• chlorpromazine one of a group of tranquilizing drugs called phenothiazines that are useful in halting psychotic episodes. Chlorpromazine, sold under the trade name Thorazine, is often used to reduce the severe...

• Clomid see fertility drug.

• clot-dissolving drug see thrombolytic drug.

• cocaine alkaloid drug derived from the leaves of the coca shrub. A commonly abused illegal drug, cocaine has limited medical uses, most often in surgical applications that take advantage of the fact that, in addition to its anesthetic effect, it...

• codeine alkaloid found in opium. It is a narcotic whose effects, though less potent, resemble those of morphine. An effective cough suppressant, it is mainly used in cough medicines. Like other narcotics,...

• cod-liver oil yellowish oil obtained from the liver of the codfish. The oil is rich in vitamin A and vitamin D (calciferol). It was long used as a preventive and cure for rickets in Baltic and Scandinavian countries, where fish is a dietary staple. However, it was not until the 1920s that doctors in the U.S. finally recognized its therapeutic usefulness. More palatable...

• colchicine alkaloid extracted from plants of the genus Colchicum and especially from the corms of the autumn crocus, Colchicum autumnale (see meadow saffron ). The metabolic effect of colchicine is not known, but it is thought that it may decrease production of lactic acid and prevent accumulation of uric acid crystals in the body, making it useful in...

• corticosteroid drug any one of several synthetic or naturally occurring substances with the general chemical structure of steroids. They are used therapeutically to mimic or augment the effects of the naturally occurring...

• cox-2 inhibitor see nonsteroidal anti-inflammatory drug.

• crack see cocaine.

• curare any of a variety of substances originally used as arrow poisons by Native South Americans in hunting and in warfare. The main active substance of curare, tubocurarine, is an alkaloid extracted from Chondodendron tomentosum, Strychnos toxifera, and other plant species. The poison produces muscle paralysis by interfering with the transmission of nerve impulses at the receptor sites of all skeletal muscle. Muscles with many nerves, such as...

• Cytoxan trade name for the drug cyclophosphamide, used to inhibit growth of tumors and rapidly proliferating cells. It is used in the treatment of leukemia, Hodgkin's disease, and lymphosarcoma and other...

• Darvon see analgesic.

• ddI and ddC: see AZT.

• Demerol see analgesic.

• deodorizer or deodorant, substance used to absorb or eliminate offensive odors. Disinfectants such as hydrogen peroxide, chlorine, and chlorine compounds eliminate odors caused by microorganisms. Adsorbent deodorizers such...

• depilatory substance used to remove hair. In preparing hides for tanning, lime is the chief depilatory. For the removal of superfluous hair from the human body, metal sulfides such as barium sulfide, sodium...

• depressant any one of various substances that diminish functional activity, usually by depressing the nervous system. Barbiturates , sedatives , alcohol, and meprobamate are all depressants. Depressants have various modes of action and effects. Some are primarily used medically to relieve emotion stress, anxiety, and tension; others induce sleep, and still others...

• DES or diethylstilbestrol , synthetic nonsteroid female sex hormone having the same physiological effects as estrogen. In the 1940s and 50s DES was mistakenly believed to reduce the risk of miscarriage and was routinely prescribed for pregnant women believed to be at risk. In fact, it was later found to increase...

• Desoxyn trade name for the drug methamphetamine hydrochloride. See amphetamine.

• Dexedrine trade name for the drug dextroamphetamine sulfate. See amphetamine.

• diethylstilbestrol see DES.

• digitalis any of several chemically similar drugs used primarily to increase the force and rate of heart contractions, especially in damaged heart muscle. The effects of the drug were known as early as 1500...

• digitoxin see digitalis.

• digoxin see digitalis.

• Dilantin trade name for diphenylhydantoin, an anticonvulsant drug. The first nonsedative antiepileptic agent, it is still widely used to control the grand mal type of epilepsy. It is also useful against types...

• disinfectant agent that destroys disease-causing microorganisms and their spores. Disinfectants, or germicides, are sometimes considered to be substances applied to inanimate bodies, whereas antiseptics , not so potent, are agents that kill microbes on living things. Mercuric chloride, carbolic acid (phenol), and chlorinated lime and other chlorine releasing compounds are disinfectants used on...

• diuretic drug used to increase urine formation and output. Diuretics are prescribed for the treatment of edema (the accumulation of excess fluids in the tissues of the body), which is often the result of underlying disease of the kidneys, liver, lungs, or heart (e.g., congestive heart failure ). They are also used to treat hypertension (high blood pressure) and glaucoma. They act on the kidneys, modifying the absorption and excretion of water and electrolytes such as sodium and potassium. Types of diuretics include thiazides, loop diuretics, and potassium-sparing...

• dopamine one of the intermediate substances in the biosynthesis of epinephrine and norepinephrine. See catecholamine.

• 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...

• echinacea popular herbal remedy, or botanical, believed to benefit the immune system. It is used especially to alleviate common colds and the flu, but several controlled studies using it as a cold medicine...

• ecstasy either of two drugs used for their euphoric effects. The original ecstasy, a so-called designer drug, also known as MDMA, is an analog of methamphetamine (see amphetamine ). The other drug is a substance...

• emetic substance that produces vomiting. Direct, or gastric, emetics, which act directly on the stomach, include syrup of ipecac , sulfate of zinc or copper, alum , ammonium carbonate, mustard in water, or copious quantities of warm saltwater. Indirect, or systemic, emetics, such as apomorphine, induce vomiting by acting indirectly through the blood on the...

• ephedra see ephedrine.

• ephedrine drug derived from plants of the genus Ephedra (see Pinophyta ), most commonly used to prevent mild or moderate attacks of bronchial asthma. Unlike epinephrine , to which it is chemically similar, ephedrine is slow to take effect and of mild potency and long duration. A bronchodilator and decongestant, ephedrine is used to relieve nasal congestion...

• ergot disease of rye and other cereals caused by the fungus Claviceps purpurea. The cottony, matlike body, or mycelium, of the fungus develops in the ovaries of the host plant; it eventually turns into a hard pink or purple body, the sclerotium, or ergot, that resembles a...

• erythromycin any of several related antibiotic drugs produced by bacteria of the genus Streptomyces (see antibiotic ). Erythromycin is most effective against gram-positive bacteria such as pneumococci, streptococci, and some staphylococci (see Gram's stain ). The antibiotic also has some effect on gram-negative bacteria and some fungi. Erythromycin inhibits protein synthesis in susceptible microorganisms. It is used to treat such diseases as pneumonia...

• fertility drug any of a variety of substances used to increase the possibility of conception and successful pregnancy. Different methods are used to correct or circumvent the many different functional disorders...

• fluoridation process of adding a fluoride to the water supply of a community to preserve the teeth of the inhabitants. Tooth enamel ordinarily contains small amounts of fluorides and when the amount is...

• fumigation see disinfectant.

• generic drug a drug sold or prescribed under the nonproprietary name of its active ingredients or under a generally descriptive name rather than under a brand or trade name. The name of the active ingredient is...

• germicide chemical substance capable of killing many different types of microorganisms; also called disinfectant.

• gramicidin antibiotic obtained from the bacterial species Bacillus brevis, which is found in soil. Gramicidin is particularly effective against gram-positive bacteria (see Gram's stain ). Because the drug is highly toxic, it cannot be administered internally and so is used only on the skin as a lotion or ointment. It is used primarily in the treatment of infected surface wounds,...

• hallucinogenic drug any of a group of substances that alter consciousness; also called psychotomimetic (i.e., mimicking psychosis ), mind-expanding, or psychedelic drug. The group includes mescaline, or peyote , which...

• hashish resin extracted from the flower clusters and top leaves of the hemp plant, Cannabis sativa, and C. indica. Hashish, called charas in India, is the most potent grade of cannabis and is obtained from cultivated plants grown in hot, moist climates. Marijuana , a cheaper and less potent substance, is usually obtained from the cut tops of plants grown in cooler climates. Like marijuana, hashish is usually smoked, but in a pipe or water pipe; in N Africa...

• heparin anticoagulant produced by cells in many animals. A polysaccharide, heparin is found in the human body and occurs in greatest concentration in the tissues surrounding the capillaries of the lungs and the liver...

• heroin opiate drug synthesized from morphine (see narcotic ). Originally produced in 1874, it was thought to be not only nonaddictive but useful as a cure for respiratory illness and morphine addiction, and capable of relieving morphine withdrawal symptoms...

• human growth hormone (HGH): see growth hormone.

• hydrocortisone another name for the steroid hormone cortisol , more especially used to refer to preparations of this hormone used medicinally. Hydrocortisone, introduced in 1952, is more potent than cortisone with...

• hyoscine see scopolamine.

• 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...

• ibuprofen nonsteroidal anti-inflammatory drug (NSAID) that reduces pain, fever, and inflammation. Along with naproxen and ketoprofen , ibuprofen belongs to the propionic acid class of NSAIDs. It was first made available in 1967. Like other NSAIDs, it acts by inhibiting the body's production of prostaglandins. Available over the counter in a variety of preparations (e.g., Advil, Motrin, Nuprin), it is commonly used to treat rheumatoid arthritis, gout, and painful menstruation. Side effects include rash,...

• immunosuppressive drug any of a variety of substances used to prevent production of antibodies. They are commonly used to prevent rejection by a recipient's body of an organ transplanted from a donor. A transplant is rejected when the recipient's immune system acts against it; current...

• insect repellent substance applied to the skin in order to provide protection against biting insects, primarily mosquitoes, ticks, chiggers, fleas, and certain flies. The most effective such substance is DEET...

• interferon any of a group of proteins produced by cells in the body in response to an attack by a virus. A cell infected by a virus releases minute amounts of interferons, which attach themselves to neighboring cells, prompting them to start producing their own protective antiviral enzymes. The...

• ipecac drug obtained from the dried roots of a creeping shrub, Cephaelis (or Psychotria ) ipecacuanha, native to Brazil but cultivated in other tropical climates. There are three varieties of the root, brown, red, and gray, varying according to the age of the plant, its place of growth, or the...

• isoniazid drug used to treat tuberculosis. Also known as isonicotinic acid hydrazide, isoniazid is the most effective antituberculosis drug currently available. The drug inhibits or kills the tubercle bacilli that cause the disease. It is...

• ketoprofen nonsteroidal anti-inflammatory drug (NSAID) with anti-inflammatory, analgesic, and fever-reducing effects, used to relieve the symptoms of headaches, arthritis, and painful menstruation. Along with ibuprofen and naproxen , it belongs to the propionic acid class of NSAIDs; it apparently acts by inhibiting the body's production of prostaglandins. Available as a prescription drug for more than 20 years in many countries, it was approved as an over-the-counter painkiller in the United States in 1995 and first marketed as Orudis KT. It is...

• laetrile name given to the chemical amygdalin, a substance derived from an extract of the kernels of many fruits, notably apricots, bitter almonds, and peaches. The idea that laetrile might selectively...

• laudanum tincture, or alcoholic solution, of opium , first compounded by Paracelsus in the 16th cent. Not then known to be addictive, the preparation was widely used up through the 19th cent. to treat a variety of disorders. Many literary and...

• laxative drug or other substance used to stimulate the action of the intestines in eliminating waste from the body. The term laxative usually refers to a mild-acting substance; substances of increasingly drastic action are known as cathartics, purgatives, hydrogogues, and drastics, respectively. Laxatives or cathartics fall into...

• l-dopa drug used to alleviate some of the symptoms of Parkinson's disease , particularly trembling, rigidity, and slow movements; the drug is also called levodopa. Parkinson's disease results when the concentration of dopamine in the brain is depleted (see catecholamine ). Medical administration of dopamine itself is ineffective since that chemical apparently does not enter the brain from the blood. A metabolic precursor of dopamine, l-dopa does enter the brain via...

• levodopa see l-dopa.

• lincomycin antibiotic isolated from bacteria of the genus Streptomyces. Similar in activity to erythromycin , it is effective against most gram-positive organisms including staphylococci, some streptococci,...

• liniment liquid preparation rubbed on skin, used to relieve muscular aches and pains. It contains some substance that when rubbed over the affected part causes mild irritation and often brings more blood to...

• LSD or lysergic acid diethylamide , alkaloid synthesized from lysergic acid, which is found in the fungus ergot ( Claviceps purpurea ). It is a hallucinogenic drug that intensifies sense perceptions and produces hallucinations, mood changes, and changes in the sense of time. It also can cause restlessness, acute anxiety, and, occasionally, depression...

• lysergic acid diethylamide see LSD.

• marihuana see marijuana.

• marijuana or marihuana, drug obtained from the flowering tops, stems, and leaves of the hemp plant, Cannabis sativa (see hemp ) or C. indica; the latter species can withstand colder climates. It is one...

• materia medica see pharmacology.

• medicinal plants plants used as natural medicines. This practice has existed since prehistoric times. There are three ways in which plants have been found useful in medicine. First, they may be used directly as...

• menthol white crystalline substance with a characteristic pungent odor. It is derived from the oil of the peppermint plant, Mentha piperita (see mint ), or prepared synthetically from coal tar. An alcohol, menthol is freely soluble in ethyl alcohol, ether, and chloroform. It is a local anesthetic and helps relieve itching, and because it imparts...

• meprobamate tranquilizing drug that acts as a depressant of the central nervous system and is commonly used in the treatment of anxiety and sometimes schizophrenia. Although meprobamate is chemically unlike barbiturates and has lower toxicity, it has similar pharmacological effects, especially the ability to induce sleep and alleviate anxiety. The drug possesses some anticonvulsant properties and is used to...

• mescaline perception-altering substance found in peyote. See hallucinogenic drug.

• methadone synthetic narcotic similar in effect to morphine. Synthesized in Germany, it came into clinical use after World War II. It is sometimes used as an analgesic and to suppress the cough reflex. ...

• methamphetamine see amphetamine ; methedrine.

• methedrine drug of the amphetamine group. Also known as methamphetamine, it is used as a stimulant.

• methotrexate drug used in halting the growth of actively proliferating tissues. Introduced in the 1950s, it is used in the treatment of leukemia , psoriasis , and non-Hodgkin's lymphoma. By binding to an enzyme...

• Miltown see meprobamate.

• mineral water spring water containing various mineral salts, especially the carbonates, chlorides, phosphates, silicates, sulfides, and sulfates of calcium, iron, lithium, magnesium, potassium, sodium, and other...

• morphine principal derivative of opium , which is the juice in the unripe seed pods of the opium poppy , Papaver somniferum. It was first isolated from opium in 1803 by the German pharmacist F. W. A. Sertürner,...

• nalorphine derivative of morphine that acts to reverse the effects of morphine and other narcotics. It counteracts narcotic-induced nervous system and respiratory system depression but is not effective against depression induced by other sedatives such as barbiturates. Nalorphine and other narcotic antagonists are useful in reversing the effects of narcotic overdoses. Because nalorphine causes withdrawal symptoms in addicts, it is administered to apparent...

• naproxen and naproxen sodium, potent nonsteroidal anti-inflammatory drugs (NSAID) used to alleviate the minor pain of arthritis, menstruation, headaches, and the like, and to reduce fever. Along with ibuprofen and ketoprofen , they belong to the propionic acid class of NSAIDs. They have been available as prescription drugs for arthritis from 1976. Naproxen sodium was approved at a low dosage as an over-the-counter...

• narcotic any of a number of substances that have a depressant effect on the nervous system. The chief narcotic drugs are opium , its constituents morphine and codeine , and the morphine derivative heroin...

• neomycin broad spectrum antibiotic effective against both gram positive and gram negative bacteria (see Gram's stain ). It interferes with protein synthesis in sensitive bacterial cells such as species of Proteus and Staphylococcus. Neomycin is mainly used topically in the treatment of skin and mucous membrane infections, wounds, and burns. Although it is also used systemically, it is highly toxic. Neomycin was first isolated...

• neostigmine drug used to mimic the effects of stimulation of the parasympathetic nervous system. Along with several other drugs that have a similar mode of action, it inhibits the action of the enzyme cholinesterase, which destroys the substance acetylcholine at nerve endings. Because neostigmine increases the effective concentration of acetylcholine, it causes such body changes as contraction of the pupils, increased activity of intestinal muscles, and...

• nonsteroidal anti-inflammatory drug a drug that suppresses inflammation in a manner similar to steroids, but without the side effects of steroids; commonly referred to by the acronym NSAID . Also effective in alleviating pain and fever, NSAIDs are commonly used to treat the symptoms of arthritis, gout, bursitis, painful menstruation, and headache. They act by inhibiting the synthesis...

• nux vomica bitter-tasting drug obtained from the poisonous seeds of Strychnos nux-vomica, a tree that grows in Sri Lanka, India, and N Australia. The dried seeds contain strychnine and brucine, both colorless crystalline alkaloids, as well as sugar, acid, and oil. In the past nux vomica was used as a tonic in the form of a tincture, or alcoholic solution, but it is not used...

• oil of wintergreen see salicylic acid.

• opiate drug any of a group of drugs derived from opium. Used medicinally to relieve pain and induce sleep, they include codeine , morphine , the morphine derivative heroin , and, formerly, laudanum. Sometimes included in the group are certain synthetic drugs that have morphinelike pharmacological action. All opiates are considered controlled substances by U.S. law and are available only by...

• opium substance derived by collecting and drying the milky juice in the unripe seed pods of the opium poppy , Papaver somniferum. Opium varies in color from yellow to dark brown and has a characteristic...

• orphan drug drug developed under the U.S. Orphan Drug Act (1983) to treat a disease that affects fewer than 200,000 people in the United States. The orphan drug law offers tax breaks and a seven-year monopoly...

• ouabain see digitalis.

• papaverine alkaloid found in opium that acts as a muscle relaxant and vasodilator. The drug relaxes the smooth muscle of the larger blood vessels and is used to increase the blood supply to the brain or to the heart, as in the...

• paraldehyde nervous system depressant similar to alcohol in its effects and used as a sedative. A colorless flammable liquid with a disagreeable odor, paraldehyde produces sleep for up to 12 hr. with little or no muscle, heart, or respiratory depression. It is often given to alcoholics...

• paregoric alcoholic solution of opium and camphor first prepared in the 18th cent. Because of the constipating effect of opium, paregoric has been used to control diarrhea. It was formerly a constituent of...

• patent medicine packaged drugs that can be obtained without prescription; the term was formerly used to describe quack remedies sold by peddlers. Patent, or proprietary, medicines are advertised to the public by trade name,...

• penicillin any of a group of chemically similar substances obtained from molds of the genus Penicillium that were the first antibiotic agents to be used successfully in the treatment of bacterial infections in humans. The antagonistic effect of penicillin on bacteria was first observed by the Scottish biologist Sir Alexander Fleming in 1928. Although he recognized the therapeutic potential of penicillin, it was not until 1941 that a group of biologists working in England, including Oxford's Sir H. W. Florey and E. B. Chain , purified the substance and established its effectiveness against infectious organisms and its lack of toxicity to humans. The first successful treatment of a patient with penicillin occurred in...

• peyote spineless cactus ( Lophophora williamsii ), ingested by indigenous people in Mexico and the United States to produce visions. The plant is native to the SW United States, particularly S Texas, and Mexico, where it grows in dry soil. The...

• phenothiazine any one of a class of drugs used to control mental disorders. Phenothiazines, along with other antipsychotic, or neuroleptic, drugs are used for such disorders as schizophrenia, paranoia, mania,...

• pilocarpine naturally occurring alkaloid obtained from plants of the genus Pilocarpus (family Rutaceae). By mimicking the effects of acetylcholine , pilocarpine acts as a stimulant of the parasympathetic nervous system. It promotes the flow of saliva and urine and increases perspiration. Because it increases the outflow of fluid from the eye, reduces the pressure within the eye, and causes the pupil to contract,...

• placebo inert substance given instead of a potent drug. Placebo medications are sometimes prescribed when a drug is not really needed or when one would not be appropriate because they make patients feel well taken care of. Placebos are also used as...

• prednisone see corticosteroid drug.

• procaine anesthetic drug, commonly called novocaine, that gives prolonged relief from pain (see anesthesia ). It is used as a local anesthetic and in rectal and other surgery. It is marketed under the trade...

• protease inhibitor any of a class of drugs that interfere with replication of the AIDS virus ( HIV ), by blocking an enzyme (protease) necessary in the late stages of its reproduction. Clinical trials of the protease inhibitor indinavir have shown it to be especially beneficial in combination...

• Prozac trade name for fluoxetine hydrochloride. See antidepressant.

• psilocybin perception-altering substance found in some species of mushroom. See hallucinogenic drug.

• psychedelic drug see hallucinogenic drug.

• psychopharmacology in its broadest sense, the study of all pharmacological agents that affect mental and emotional functions. The term is usually applied more specifically to the study and synthesis of drugs used in...

• psychotomimetic drug see hallucinogenic drug.

• quinidine heart muscle relaxant used to maintain regular heart rhythm patterns. It is an alkaloid chemically similar to quinine and, like quinine, occurs naturally in some species of cinchona trees. Quinidine slows the rate of blood flow in heart chambers and lowers the excitability of the muscle. Quinidine is a general...

• quinine white crystalline alkaloid with a bitter taste. Before the development of more effective synthetic drugs such as quinacrine, chloroquine, and primaquine, quinine was the specific agent in the...

• reserpine alkaloid isolated from the root of the snakeroot plant ( Rauwolfia serpentina ), a small evergreen climbing shrub of the dogbane family native to the Indian subcontinent. Known in India as Sarpaganda, it was used for centuries to treat insanity as well as physical illnesses...

• rifampin antibiotic used in the treatment of tuberculosis. It is also used to eliminate the meningococcus microorganism from carriers and to treat leprosy , or Hansen's disease. Rifampin, or rifampicin as it was formerly called, acts by inhibiting protein synthesis in sensitive cells. It is a toxic drug whose side effects include flulike symptoms...

• salicylate any of a group of analgesics , or painkilling drugs, that are derivatives of salicylic acid. The best known is acetylsalicylic acid, or aspirin. Now often made synthetically, they were originally derived from salicin, the active ingredient in willow bark, used for centuries in the treatment of pain and fever. Salicylates also occur naturally in many plants used as foods (e.g., strawberries, almonds, tomatoes)...

• scopolamine or hyoscine , alkaloid drug obtained from plants of the nightshade family (Solanaceae), chiefly from henbane , Hyoscyamus niger. Structurally similar to the nerve substance acetylcholine , scopolamine acts by interfering with the transmission of nerve impulses by acetylcholine in the parasympathetic nervous system and produces symptoms typical of parasympathetic system depression: dilated pupils, rapid heartbeat, and dry skin, mouth, and respiratory passages. Because scopolamine depresses the central nervous...

• sedative any of a variety of drugs that relieve anxiety. Most sedatives act as mild depressants of the nervous system, lessening general nervous activity or reducing the irritability or activity of a specific organ. Sedatives taken in small quantities are useful in relieving coughing, nausea,...

• skin patch   transdermal patch, or transdermal delivery system, adhesive patch used to deliver a controlled dose of a drug through the skin over a period of time. A skin patch uses a special membrane to control the rate at which the liquid drug contained in the...

• sleeping pill a pill containing medication that induces sleep. Benzodiazepines such as temazepam (Restoril) and triazolam (Halcion) have for the most part replaced barbiturates as drugs of choice for insomnia. Imidaopyridines, such as zolpidem tartrate, are also sometimes used for short-term treatment; they are nonbenzodiazepines but work by acting on benzodiazepine...

• stimulant any substance that causes an increase in activity in various parts of the nervous system or directly increases muscle activity. Cerebral, or psychic, stimulants act on the central nervous system and provide a temporary sense of alertness and well-being as well as relief from fatigue...

• streptomycin antibiotic produced by soil bacteria of the genus Streptomyces and active against both gram-positive and gram-negative bacteria (see Gram's stain ), including species resistant to other antibiotics, e.g., some streptococci, penicillin-resistant staphylococci, and bacteria of the genera Proteus and Pseudomonas. Originally isolated by Selman A. Waksman and Albert Schatz in 1947, streptomycin is effective against tubercle bacilli and is a mainstay of tuberculosis therapy. Because streptomycin-resistant...

• strychnine bitter alkaloid drug derived from the seeds of a tree, Strychnos nux-vomica, native to Sri Lanka, Australia, and India. It has been used as a rat poison for five centuries, and rat biscuits still remain a cause of accidental poisoning in humans. Strychnine is a potent...

• sulfa drug any of a class of synthetic chemical substances derived from sulfanilamide, or para-aminobenzenesulfonamide. Sulfa drugs are used to treat bacterial infections, although they have largely been...

• sympathomimetic drug any of a group of substances whose actions resemble the response of stimulated sympathetic nerves (see nervous system ). These drugs include epinephrine and other catecholamines that are naturally...

• tamoxifen synthetic hormone used in the treatment of breast cancer. Introduced in 1978, tamoxifen is used to prevent recurrences of cancer in women who have already undergone surgery to remove their tumors. In 1998, a large study of healthy women at high risk for...

• tetracycline any of a group of antibiotics produced by bacteria of the genus Streptomyces. They are effective against a wide range of Gram positive and Gram negative bacteria, interfering with protein synthesis in these microorganisms (see Gram's stain ). Tetracycline is used to treat rickettsial bacterial infections such as Rocky Mountain spotted fever, some eye, respiratory, intestinal, and urinary infections, some kinds of acne, and some...

• thalidomide sleep-inducing drug found to produce skeletal defects in developing fetuses. The drug was marketed in Europe, especially in West Germany and Britain, from 1957 to 1961, and was thought to be so...

• thrombolytic drug or clot-dissolving drug, substance, such as streptokinase or tissue plasminogen activator (tPA), that causes the breakdown of blood clots (see thrombosis ) that obstruct the flow of blood through...

• thyroxine