Drug is one of the medical profession’s most valuable tools. Doctors prescribe drugs to treat or prevent many diseases. Every year, penicillin and other germ-killing drugs save the lives of countless victims of meningitis, pneumonia, and other dangerous infectious diseases. Vaccines prevent such diseases as measles, polio, and smallpox. Analgesics lessen or eliminate pain. The use of these and many other kinds of drugs has helped millions of people live longer, healthier lives than would otherwise have been possible.

Most of our useful drugs were unknown before the 1900’s. For example, the sulfa drugs and antibiotics, our best germ-fighting drugs, did not come into use until the late 1930’s and early 1940’s. Before that time, about 30 percent of all pneumonia victims in the United States died of the disease. The new drugs quickly reduced the death rate from pneumonia in the United States to less than 5 percent.

Polio vaccine was introduced in 1955. At that time, the polio virus infected about 30,000 to 50,000 people every year in the United States. By 1960, use of the vaccine had reduced the number of new polio cases in the United States to about 3,000 a year. In 1900, most Americans did not live past the age of 47. Today, Americans live an average of more than 70 years, in part because of the use of modern drugs.

But drugs can also cause sickness and death. Any drug, even a relatively safe one, may cause harm if it is used improperly. Aspirin, for example, is one of the safest and most useful drugs. Yet every year, aspirin kills children who mistake the tablets for candy and eat too many of them. Any drug can kill if it is taken in a large enough dose. In addition, the widespread misuse of alcohol, cocaine, heroin, and other addictive drugs has become a serious problem.

We generally use the word drugs to mean only medicines and certain other chemical substances that people use, such as alcohol or marijuana. But pharmacologists, the scientists who study drugs, consider all chemicals that affect living things to be drugs. For example, they classify insecticides, weedkillers, and a wide variety of other substances as drugs. Even the chemicals in automobile exhaust and other substances that pollute the environment act like drugs because they affect living things.

This article deals primarily with drugs that are used for medical purposes. Detailed information dealing with the misuse of drugs can be found in the article Drug misuse.

Kinds of drugs

The many kinds of drugs people use can be classified in several ways. They can be grouped according to their form, such as a solid, gas, or liquid. Or they can be classified according to the way they are taken, such as by swallowing, inhaling, or injection. Drugs can also be grouped according to their chemical structure.

Pharmacologists generally classify drugs according to the major beneficial effect they have on the body. Many of the most widely used drugs belong to one of several dozen groups. Four especially important groups are (1) drugs that fight infection, (2) drugs that prevent infectious diseases, (3) drugs that affect the heart and blood vessels, and (4) drugs that affect the nervous system.

All drugs affect the body in more than one way. For example, some drugs taken to act on the nervous system also affect the heart. The action of these drugs on the heart is considered a side effect. The drugs discussed in this section, however, are classified according to their chief effect on the body.

Drugs that fight infection

Drugs that kill or help prevent multiplication of bacteria or viruses that infect the body are called antimicrobials. Antimicrobials that act against bacteria include antibiotics and sulfonamides (sulfa drugs). Antibiotics are obtained from naturally occurring microorganisms. Sulfonamides are prepared synthetically. A large dose of penicillin or certain other antibiotics kills disease-causing bacteria. A smaller dose of such an antibiotic keeps the bacteria from multiplying in the body and thus allows the body’s natural defenses to destroy them. Sulfonamides also prevent bacteria from multiplying in the body. In most cases, however, sulfonamides and other synthetic antimicrobials do not kill the bacteria. See Antibiotic; Sulfa drug.

Doctors prescribe antiviral drugs to treat certain diseases caused by viruses. For example, the antiviral drug zidovudine, commonly called AZT, is used in the treatment of AIDS.

Drugs that prevent infectious diseases

Two kinds of drugs prevent infectious diseases. They are (1) vaccines and (2) antiserums and globulins. Some of these drugs, such as polio vaccines, are especially valuable because there is no effective treatment for the disease they prevent.

Vaccines

contain a weakened or killed form of the microbe that causes a particular disease. There are several kinds of vaccines. Each kind causes the body to produce substances, which are called antibodies, that fight a particular disease. The vaccine thus makes the body immune to the disease by providing resistance against attack by it. Vaccines have been developed against such infectious diseases as cholera, diphtheria, hepatitis, measles, and smallpox, as well as polio. In fact, vaccinations against smallpox have wiped out that disease. See Immunization.

Antiserums and globulins,

like vaccines, prevent certain infectious diseases. But unlike vaccines, these drugs contain antibodies rather than substances that cause the body to produce antibodies. The antiserums and globulins act more quickly than vaccines to prevent infection but give only temporary protection. Physicians prescribe these drugs after a person who has not been vaccinated is exposed to an infectious disease. Antiserums are used against such diseases as diphtheria and tetanus (lockjaw). Examples of diseases against which globulins protect include hepatitis, rabies, and tetanus. See Serum; Globulin.

Drugs that affect the heart and blood vessels

Drugs that affect the heart and blood vessels are known as cardiovascular drugs. Doctors prescribe them in treating diseases of the heart and blood vessels. Such diseases rank as the chief cause of death from disease in the United States, Canada, and many other countries. There are four major kinds of cardiovascular drugs: (1) antiarrhythmics, (2) cardiotonics, (3) vasodilators, and (4) antihypertensives.

Antiarrhythmics

steady the heartbeat. People take these drugs to treat tachycardia and fibrillation, conditions in which the heart beats irregularly and at a rate much faster than normal.

Cardiotonics

strengthen the heartbeat. These drugs cause the heart to beat more forcefully and thus increase circulation of the blood. Physicians prescribe them to treat conditions in which the heart pumps too weakly. The most widely used cardiotonic drugs are digoxin and digitoxin.

Vasodilators

enlarge, or dilate, small blood vessels. These drugs are taken mostly to treat narrowing of the coronary arteries, the vessels that supply blood to the heart muscle. Drugs used to enlarge these arteries are called coronary vasodilators. Doctors prescribe them for people with such severe narrowing of the coronary arteries that they suffer chest pains while walking or exercising in some other way. Such persons are said to have angina pectoris. The most widely used coronary vasodilators are isosorbide dinitrate and nitroglycerin. Other kinds of drugs used in treating angina include calcium channel blockers and beta-blockers.

Antihypertensives

are used in the treatment of hypertension (high blood pressure). Vasodilators and many other kinds of drugs are antihypertensives. Vasodilators lower blood pressure by causing the muscles in the walls of small blood vessels to relax. The blood is then able to flow at a lower pressure. Other antihypertensives act differently. Often, two or more kinds are given daily to the same patient.

Other cardiovascular drugs.

Antihyperlipidemics are drugs that lower levels of cholesterol and other blood lipids (fats) in the treatment of atherosclerosis. They include lovastatin, gemfibrozil, and pravastatin. Anticoagulants, such as heparin and warfarin, help prevent blood clotting. Thrombolytics are used to break up blood clots. They are especially useful in treating clots that form in the coronary arteries and can cause heart attacks. Widely used thrombolytics include tissue plasminogen activator and streptokinase.

Drugs that affect the nervous system

Many of the most widely used drugs affect the brain and other parts of the nervous system. These drugs include alcohol; the caffeine in cocoa, coffee, and tea; cocaine; marijuana; narcotics; and sleeping pills. Altogether, five major kinds of drugs affect the nervous system: (1) analgesics, (2) anesthetics, (3) hallucinogens, (4) stimulants, and (5) antianxiety and hypnotic drugs.

Analgesics

relieve pain without causing unconsciousness or diminishing the other senses, such as the sense of touch or taste. For example, an analgesic may relieve a person’s headache, but it will not prevent that person from feeling heat or cold or from tasting food.

There are two main kinds of analgesics: (1) narcotics (also known as opioid analgesics) and (2) nonnarcotics. Both kinds relieve pain. But narcotics also produce drowsiness, a dazed condition, and often a feeling of well-being. Aspirin and acetaminophen are two commonly used nonnarcotic analgesics. Widely used narcotics include codeine and morphine, both prepared from the opium poppy plant.

When pain is severe, physicians often prescribe a narcotic. For example, morphine is used to relieve the pain of severe injury and of cancer. But excessive use of narcotics leads to drug addiction, a condition in which a person has become so dependent on the drug that illness results if use of the drug is stopped. For this reason, physicians prescribe narcotics only if other analgesics will not work. See Narcotic.

Anesthetics

eliminate sensation. General anesthetics eliminate sensation throughout the body, thus causing unconsciousness. These drugs, which include enflurane, halothane, and thiopental, are given during many kinds of surgical operations. Local anesthetics deaden the senses only in the area of the body to which they are applied. Dentists often give such local anesthetics as lidocaine and procainelike agents. Doctors use local anesthetics for eye surgery and other operations that do not require the patient to be unconscious. See Anesthesia.

Hallucinogens

cause a person to hallucinate—that is, to see, hear, or otherwise sense something that exists only in the mind. These drugs are also called psychedelic (mind-revealing) drugs. They affect the senses, emotions, and reasoning, and at higher doses they may cause states resembling mental illness. Hallucinogenic drugs include LSD, marijuana, mescaline, and PCP. Physicians have experimented with hallucinogens in treating mental illness. See Hallucinogenic drug.

Stimulants

overcome sleepiness and tiredness. These drugs stimulate, or increase the activity of, the nervous system. Stimulants include caffeine, cocaine, and synthetic drugs known as amphetamines. Common names for amphetamines include “speed,” “uppers,” and “wakeups.” Stimulants create a sense of well-being in most users, in addition to increasing mental and physical activity. However, many people become depressed and uneasy as the effects of the stimulants wear off. They may then take the drug again to feel better, and they thus become dependent on it. For this reason, doctors seldom prescribe stimulants for tiredness. See Amphetamine; Stimulant.

Antianxiety and hypnotic drugs

reduce tension and worry by altering the nervous system. They include tranquilizers, sedatives, and alcohol.

Tranquilizers

calm a person without causing much drowsiness if taken in a small enough dose. Larger doses may make the user sleepy as well as calmer. However, even the use of mild tranquilizers over a long period of time may make the user dependent on these drugs. Psychiatrists prescribe antipsychotic drugs (sometimes called major tranquilizers) and antidepressant drugs for people who have severe mental disorders. These drugs may reduce a patient’s extreme fears, worries, and distortions of thought. See Tranquilizer.

Sedatives,

like tranquilizers, have a calming effect. But sedatives have greater ability than tranquilizers to make a person sleepy. As a result, physicians generally prescribe sedatives for patients who suffer from insomnia (the inability to sleep naturally). Barbiturates, also known as “barbs,” “downers,” and “goofballs,” were once used widely as antianxiety drugs and sedatives. But because they are addictive and easily misused, they have been largely replaced by safer drugs. The class of drugs known as benzodiazepines are now the most widely used tranquilizers and sedatives. These drugs include diazepam (for example, Valium) and triazolam (Halcion).

Alcohol

is the common name for ethyl alcohol, the drug found in alcoholic drinks. It relaxes most people and makes them drowsy. The use of alcohol, like the use of most other drugs that depress the nervous system, may make a person dependent on it. See Alcoholism.

Other kinds of drugs

People also use many other kinds of drugs besides those discussed above. These drugs include (1) diuretics, (2) hormones, (3) vitamins, (4) antitumor drugs, and (5) immunosuppressive drugs.

Diuretics

increase the formation of urine. In certain diseases, the kidneys do not produce enough urine. As a result, fluid, salts, and wastes build up in the body. Diuretics correct this condition by causing the kidneys to produce more urine. Diuretics are also used to treat hypertension. See Diuretic.

Hormones

are chemicals made by the body’s glands. The hormones control many body functions, such as growth and reproduction. Certain animal hormones are similar to those produced by people, and scientists have created synthetic hormones. Natural and synthetic hormones are used as drugs in several ways.

Physicians prescribe hormones for patients whose glands produce insufficient amounts. For example, some people who have the disease diabetes mellitus do not produce enough of the hormone insulin. They must receive insulin injections. Doctors also prescribe hormones to treat diseases that do not result from a hormone deficiency. The hormones ACTH and cortisol, for example, are used in treating rheumatoid arthritis.

Hormones are also used as oral contraceptives, or birth control pills, which prevent pregnancy. These drugs work by interfering with the normal reproductive processes in a woman’s body. See Hormone; Birth control (Methods of birth control).

Vitamins

are essential to good health. Such diseases as rickets or scurvy develop if a person has certain vitamin deficiencies. The best way for a person to obtain vitamins is to eat a well-balanced diet. But if necessary, a physician may prescribe vitamin pills or injections. See Vitamin.

Antitumor drugs

destroy cancer cells. Although many such drugs have been developed, they all injure normal cells as well as cancer cells. But some antitumor drugs have been used to lengthen the life of patients with incurable cancer. Scientists hope to develop drugs that will destroy only cancer cells.

Immunosuppressive drugs.

If foreign proteins somehow get into the bloodstream, they act as antigens, causing white blood cells to make antibodies against them (see Immune system). This process also occurs when an organ from one person is transplanted into another person. The antibodies formed begin to destroy the transplanted organ. Immunosuppressive drugs interfere with the body’s formation of antibodies.

One use of immunosuppressive drugs is to prevent the destruction and rejection of transplanted organs. Azathioprine and cyclosporine are examples of immunosuppressive drugs.

How drugs work

Different drugs are administered (given) in different ways. But once in the body, almost all drugs work the same way—by altering the speed of cell activities.

Entrance into the body.

Most drugs are administered orally. But drugs may also be given in several other ways. For example, they may be injected, inhaled, or applied to the skin. The method of administration depends on the form and purpose of a drug. An anesthetic gas, for example, must be inhaled to produce unconsciousness. Ointments are applied directly to the area being treated.

Each method of administration has advantages and disadvantages. For example, the easiest and safest way to take a drug is by swallowing it. But some drugs cannot be taken orally because stomach juices destroy them. Injected drugs act quickly in the body. But injection is somewhat painful, and it presents greater risk of infection than do other methods of administration.

Researchers are constantly developing new methods of administration. A device called a transdermal patch contains a layer of medication and is attached to the skin like a bandage. The patch slowly and continuously releases the drug, which seeps through the skin to the bloodstream. The coronary vasodilator nitroglycerin may be administered in this way. Another device, the implantable pump, consists of a small, metal disk with a chamber that can be filled with a drug. The pump is inserted in the body surgically and delivers the medication continuously. It may be refilled by injection.

Action in the body.

Most drugs that are swallowed, inhaled, or injected enter the bloodstream and travel throughout the body. They pass from the blood into the cells of the tissues where the drug action occurs. Only a few kinds of drugs—such as eye drops, local anesthetics, and nasal sprays—act before entering the bloodstream. When these drugs eventually enter the blood, the amount is usually too small to produce additional effects on the cells.

Almost all drugs create their effects by altering cell activities. To explain how drugs act on cells, pharmacologists developed the receptor theory. According to this theory, chemical reactions in every living cell control the cell’s activities. Each controlling reaction causes a particular cell activity to begin, to speed up, or to slow down. A drug acts on a cell by altering one or more of these chemical reactions. It does so by attaching to receptor molecules in each cell that are normally involved in the controlling chemical reaction.

The receptor theory not only explains how drugs work, but it also points up what drugs can and cannot do. Because they react with receptors that control cell activities, drugs can only alter the speed of those activities. They cannot create new cell activities.

In most cases, the chemical reaction between a drug and the body is not a one-way process. Drugs alter cell activity, but normal body processes also change most drugs. These processes transform a drug into one or more new substances, most of which are weaker than the original drug. This changing of drugs is called biotransformation or drug metabolism. It is one way in which the body protects itself against drugs. Most biotransformation occurs in the liver. A diseased liver takes longer than a healthy liver to change a drug into a weaker substance. As a result, physicians generally reduce drug dosage for a patient with liver disease. Otherwise, the drug would last longer in the body and thus exert too great an effect.

Effect on the body.

All drugs can affect the body in both helpful and harmful ways. For example, a particular drug may produce a stronger heartbeat, relief from pain, or some other desired effect. But that drug, like all drugs, can also cause undesired effects—especially if the dose is too large.

Most drugs produce changes throughout the body because the drugs circulate through the bloodstream. As a result, most drugs used to affect one part of the body also affect other parts. For example, physicians sometimes prescribe morphine to relieve pain. Morphine alters the activities of cells in the brain and spinal cord and thus reduces the sensation of pain. But morphine also alters the function of cells in the body that are not involved in sensing pain. It may decrease the rate of breathing, cause vomiting, produce constipation, and create other undesired effects.

In general, a drug’s effects are strengthened as the dose is increased and weakened as the dose is decreased. But all people do not react the same to a change in the dose of a drug. Doubling the dose, for example, may triple the strength of the drug effects in one person and not increase the effects in someone else.

The section Kinds of drugs describes the chief desired effects of various drugs. Effects other than those desired are called adverse reactions. Drugs produce three main kinds of adverse reactions: (1) side reactions, (2) hypersensitivity reactions, and (3) toxic reactions. The repeated use of alcohol, narcotics, and certain other drugs may create a condition called drug dependence.

Side reactions,

or side effects, occur with all drugs. Physicians can anticipate these reactions and tell a patient what to expect. For example, many of morphine’s harmful effects are side reactions and should therefore be expected. Most drugs cause weak side reactions that do not prevent use of the drug.

Hypersensitivity reactions,

also called allergic reactions, occur only in persons allergic to a particular drug. Some of these reactions are minor but others are severe. Any drug may cause an allergic reaction in people highly sensitive to that drug. Some people cannot take such common drugs as aspirin or penicillin because they are allergic to them.

Toxic reactions

result from drug poisoning. Such reactions damage cells and may kill a person. All drugs can have a mild toxic effect, and a large enough overdose of any drug will produce a severe toxic reaction.

Drug dependence.

People who repeatedly take large amounts of such drugs as alcohol, amphetamines, barbiturates, or narcotics may become dependent on the drugs. These people have an intense psychological or physical need for a drug’s effects. Tolerance, or resistance to a drug’s effects, usually develops along with drug dependence. As drug use continues, tolerance increases. The drug user must thus take larger and larger doses to obtain the desired effects. The development of physical or psychological dependence, or both, is commonly called drug addiction. In most cases, a severe withdrawal illness occurs if a person stops taking the drug. See Drug misuse.

Elimination from the body.

The body eliminates drugs with other waste materials. Most drugs travel from the cells through the bloodstream to the kidneys and are eliminated in the urine. The body also eliminates drugs in sweat, tears, and solid wastes. Some anesthetics are eliminated almost entirely in exhaled breath.

How drugs are produced and sold

The production and sale of drugs used as medicines is a big business in many countries. The world’s leading producers include France, Germany, Japan, Switzerland, the United Kingdom, and the United States. This section deals chiefly with the production and sale of drugs in the United States.

Sources of drugs

The drug, or pharmaceutical, industry produces mostly synthetic drugs. Chemists working in the laboratories of drug companies create these drugs from chemical elements. Other drugs produced by the pharmaceutical industry are obtained from plants, molds, animals, minerals, and genes and bacteria.

Chemical laboratories.

Chemists have created many of our most valuable medicines. Most of these drugs do not occur naturally. Synthetic drugs duplicate or improve upon those obtained from plants, molds, bacteria, animals, or minerals. Pharmaceutical companies can produce many of these drugs at less cost and in greater quantity synthetically than by using the natural source. For example, the hormone cortisol, used to treat arthritis and many other ailments, can be obtained from the adrenal glands of cows and sheep. But drug companies can produce it cheaper synthetically. In addition, the synthetic form of cortisol causes fewer adverse reactions than the natural form of the hormone.

Plants and molds.

Drug companies make several important medicines from plants and molds. These medicines include antibiotics, cardiotonics, and certain analgesics. For example, the antibiotic penicillin comes from a mold. The cardiotonic digitalis, a drug used to stimulate the heart, is obtained from the leaves of the purple foxglove, a flower. The pain reliever morphine is taken from opium, a drug that comes from the juice of the opium poppy. Plant drugs that pharmaceutical companies do not produce include such illegal drugs as marijuana and mescaline.

Animals.

A number of important drugs—including several of the hormones used to treat arthritis, hormone deficiencies, and various other ailments—are obtained from the cells and tissues of animals. For example, millions of diabetes victims use insulin obtained from the pancreas of cattle and hogs. Physicians prescribe the hormone thyroxine, obtained from the thyroid gland of cattle and hogs, for patients whose thyroid gland produces too little of the hormone.

Minerals.

Pharmaceutical companies produce several common drugs from minerals. For example, the mineral iodine is used in making tincture of iodine, a liquid that helps prevent infection when applied to cuts.

Genes and bacteria.

Biologists and chemists have developed methods of genetic engineering by which human genes are inserted into bacterial cells or, occasionally, animal cells. The genetically altered bacterial or animal cells manufacture a chemical substance identical to one that is made by human cells. The substance is then isolated and purified so it can be administered to patients whose bodies cannot make enough of it. Examples of drugs produced in this way include erythropoietin, a hormone that stimulates production of red blood cells; tissue plasminogen activator, a protein that dissolves blood clots and can stop a heart attack; and insulin, a hormone that controls the disease diabetes. See Genetic engineering.

Research and development

Pharmaceutical firms are continually developing new drugs. Although company chemists discover some new drugs by accident, the creation of most new products begins with an idea. This idea may be for a new kind of drug or for one that works better than existing drugs. A pharmaceutical company must then obtain such a drug, test it, and develop it into a safe, easy-to-use form. The entire process takes on average about 14 years and costs many millions of dollars.

Creating a new drug

is the task of a company’s research chemists. They may make a new chemical compound or obtain the drug from a natural source. This work may take many months or even years. For example, researchers for one United States drug company spent two years testing soil from all parts of the world to find new antibiotics. The tests involved over 100,000 soil samples. The project resulted in the development of the antibiotic Terramycin, used to treat such diseases as bronchitis, pneumonia, and whooping cough.

In the process of creating a new drug, researchers perform tests with animals to see if the substance is safe and effective. They first give the substance to small animals, such as rats, mice, and guinea pigs. If the substance passes these tests, it is given to larger animals, such as dogs and monkeys. Researchers may test hundreds of substances before finding one that appears safe and effective. They then try to find out how this drug works, in what forms it can be given, how the animal body eliminates the drug, and what side effects it may have. The drug company then sends this and other information about the drug to the U.S. Food and Drug Administration (FDA)—a U.S. government agency—and asks for permission to conduct tests on people.

Testing with people.

After receiving FDA approval, a drug company performs two series of clinical tests with the new drug. The company first tests the drug for safety in healthy human volunteers. If the results of these tests are satisfactory, the company checks the drug further in patients who have the disorder the drug is designed to correct.

Most clinical tests are supervised by a clinical investigator, a physician employed by the drug firm’s research department. Physicians on university hospital staffs cooperate with the clinical investigator by arranging for volunteers to take part in the second series of tests. The number of patients who get the drug and the length of the tests depend on the disorder and the drug being tested. Most tests involve hundreds of patients and last from several months to a year. Some tests, however, involve thousands of patients and last several years.

Careful testing is one of a pharmaceutical company’s most important responsibilities. Drug companies and the FDA constantly guard against the possibility of a harmful drug being sold to the public. But even the most careful testing cannot always reveal the possibility that a drug might produce an unexpected harmful effect. A tragic example of such an unexpected effect occurred in Europe during the early 1960’s. Thousands of pregnant women who took a new sedative, thalidomide, gave birth to babies with no arms or legs or with some other deformities. The chances of such severe effects occurring unexpectedly are, however, very small.

The drug company’s clinical investigator and other scientists evaluate the results of the clinical tests. They also compare the new drug with those already in use. Other physicians and scientists continue to study the effects of the drug in animals. If the company decides it has developed a safe, effective drug, it will submit a new drug application (NDA) to the FDA requesting approval to sell the drug. The section The new drug application describes this step in drug production.

Developing the finished product.

Before selling a new drug, a company must develop it into a safe, easy-to-use form. Researchers determine what ingredients to add to the drug to make it into a capsule, liquid, tablet, or other usable form. These ingredients, called excipients, must not interfere with the drug’s action. Researchers also determine how fast the drug will break down chemically and lose its effectiveness. The company can include this information on the label if the breakdown occurs quickly. After all these steps, the company is ready to plan mass production of the drug.

Mass production

During research and development, a company produces only small quantities of a drug. The firm must determine whether the process used to produce small amounts will work for large-scale production. The company usually conducts production tests in an experimental pilot plant before beginning mass production. These production tests may indicate that small-scale methods must be changed. Sometimes these tests indicate that a new plant must be built to produce the drug.

A company has to plan its mass-production schedule carefully. If the firm produces too much of a drug, some of it might break down chemically and become worthless before it is sold. The company must also make certain that all batches of the drug have been made correctly. Samples of each batch are inspected. If such spot-checking reveals an error, the entire batch is either processed again or destroyed.

Distribution and sale

A new drug may be distributed and sold in one of two ways, depending on whether it is a prescription drug or a nonprescription drug. Prescription drugs may be sold only by a pharmacist and only if prescribed by a physician or dentist. Nonprescription drugs need not be sold by pharmacists and do not require a prescription. The FDA determines whether a drug may be sold as a prescription or nonprescription drug.

Prescription drugs

include antibiotics, barbiturates, and certain tranquilizers. Because these drugs require a prescription, pharmaceutical companies direct their sales efforts for these drugs at physicians and dentists. The companies place advertisements in professional journals, mail out literature, and set up advertising displays at medical and dental meetings. Most drug firms also employ medical service representatives who call on doctors to tell them about the firm’s products.

Nonprescription drugs,

such as aspirin and some cough medicines, are considered safe enough to be sold over the counter (OTC)—that is, without a prescription from a physician or dentist. A drugstore, grocery store, department store, or any other establishment may sell such drugs. As a result, pharmaceutical firms advertise nonprescription drugs widely to the public.

Drug names

All drugs produced by the U.S. pharmaceutical industry are given at least two names: (1) a chemical name and (2) a United States Adopted Name (USAN). In addition, a drug may have one or more trade names, or trademarks. For example, a certain diuretic has the chemical name 6-chloro-3-4-dihydro-2H-1,2, 4-benzothiadiazine-7-sulfonamide-1,1-dioxide. Its USAN is hydrochlorothiazide. The drug also has more than 20 trade names, including Esidrix, HydroDIURIL, and Oretic.

The chemical name

of a drug describes its chemical structure. It is the only name that identifies a drug exactly. But because most drugs have long, difficult chemical names—such as the above example—these names are not commonly used.

The United States Adopted Name,

commonly referred to as the generic name, is usually an abbreviated chemical name. It provides a hint about a drug’s chemical structure, as the name hydrochlorothiazide does in the example. But the USAN does not describe a drug fully. The USAN is shorter than the chemical name and easier to use. The USAN Council, made up of pharmacists and scientists in other fields, selects all USAN’s.

The trade name

is given to a drug by the company that sells it. A number of firms may sell a particular drug. Each company may give the drug a different trade name, or it may market the drug under the drug’s generic name. A drug may have 10, 20, or more trade names. State laws vary concerning prescriptions written for trade-named drugs. In some states, if a doctor prescribes a drug by its trade name, a pharmacist must fill the prescription with the trademarked drug. But in other states, a pharmacist may substitute a lower-priced trademarked or generic equivalent, as long as the doctor has not specifically prohibited such substitution. In still other states, a pharmacist may substitute an equivalent only if the doctor has indicated that such substitution is permissible. If a doctor prescribes a drug by its generic name, a pharmacist may fill the prescription with a suitable drug sold by any company.

Drug regulation

Almost all countries have laws regulating the manufacture, sale, and use of drugs. In the United States, every new drug that is sold must be approved by the FDA. In addition to approval of the drug, the FDA inspects factories that manufacture drugs, and it checks the quality of drug samples that are taken from stores.

The United States Drug Enforcement Administration works to end the illegal use of narcotics and other misused drugs (see Drug Enforcement Administration). In addition, many states have laws concerning the manufacture, sale, and use of drugs. In Canada, the manufacture and sale of drugs is regulated by Health Canada, a federal agency.

U.S. drug laws.

The Federal Food, Drug, and Cosmetic Act of 1938 outlaws the sale of impure and falsely labeled drugs. It also requires manufacturers to prove to the FDA that a new drug is safe before they may sell it. In addition, the law requires that drug labels list active ingredients, directions for use, and warnings of possible harmful effects. Under the Drug Amendments Act of 1962, drug companies must prove that a new product is effective and safe. In 1975, the FDA issued regulations to ensure that all trade-named and generic equivalents of the same drug have identical actions in the body. In 1978, the FDA issued rules requiring that the labels of all prescription drugs and most nonprescription drugs carry an expiration date to show how long the drug will remain fully effective. The FDA controls advertising of prescription drugs. The Federal Trade Commission (FTC) controls advertising of nonprescription drugs.

The Comprehensive Drug Abuse Prevention and Control Act of 1970 strengthened federal regulation of the manufacture, sale, possession, and use of narcotics and other misused drugs. The act also called for increased federal assistance in the treatment of drug-dependent persons.

The Orphan Drug Act of 1983 encourages drug manufacturers in the United States to work with new drugs that can be used in the treatment of rare diseases. Such drugs are often referred to as orphan drugs because pharmaceutical firms cannot afford to develop them. Research and marketing costs would exceed income from sales of the drugs. The Orphan Drug Act includes regulations that help reduce the expenses of developing and marketing orphan drugs. In addition, the act provides federal grants to pay for some of the costs of research and development.

The Federal Anti-Tampering Act of 1983 prohibits tampering with containers or labels for foods, drugs, or cosmetics. The act’s purpose is to prevent unintentional use of incorrectly labeled or contaminated products.

The new drug application.

In seeking FDA approval to sell a new drug, a drug company must submit a new drug application (NDA). The application must contain detailed information about the drug, including four important items: (1) records of tests that prove the drug is both safe and effective, (2) an account of the drug’s composition, (3) a description of the methods used to manufacture the drug, and (4) the information to be included on the drug label. The company must also provide the FDA with samples of the drug and its ingredients.

FDA scientists study each new drug application and conduct tests, if necessary, with the samples from the drug company. If they approve a drug, these scientists decide whether it will be sold as a prescription or nonprescription drug.

Drug standards.

In the United States, standards of drug composition are established by The United States Pharmacopeia-The National Formulary (USP-NF). Federal law recognizes this publication as the official authority on drug standards. The USP-NF is revised continuously by a committee of the United States Pharmacopeial Convention. Each convention is attended by representatives from schools of medicine and pharmacy; from various federal agencies; and from associations of physicians, dentists, and pharmacists.

History

Prehistoric peoples probably used drugs long before civilizations arose. It is likely they discovered that aches and pains disappeared after eating certain plants. They may have also noticed that animals ate certain plants only when ill and then recovered. Prehistoric people probably then ate the same plants when they felt sick.

Drugs in ancient times.

The oldest known written record of drug use is a clay tablet from the ancient Sumerian civilization of the Middle East. This tablet, made in the 2000’s B.C., lists about a dozen drug prescriptions. An Egyptian scroll from about 1550 B.C. names more than 800 prescriptions containing about 700 drugs. The ancient Chinese, Greeks, and Romans also used many drugs. Most of the remedies were useless. Occasionally, people who had taken useless remedies recovered naturally. As a result, they thought the drugs were responsible. However, ancient peoples did discover some effective drugs. The Greeks and Romans, for example, used opium to relieve pain. The Egyptians used castor oil as a laxative.

Drugs in the Middle Ages.

During the Middle Ages, which lasted from about the A.D. 400’s through the 1400’s, interest in learning and science declined in Europe. As a result, Europeans produced little new information about drugs. But in the Middle East, Arab physicians added new discoveries to the knowledge of drugs they had acquired from the ancient Romans and Chinese. The Arabs later passed on their knowledge of drugs to Europeans.

Throughout the Middle Ages, the demand for drugs remained high, and pharmacies became increasingly common in Europe and the Arab world. But scientists had not yet learned how the human body functions, what causes infectious disease, or how drugs work. As a result, people continued to take many useless or harmful drugs, in addition to some effective ones.

Scientific advances.

In the 1500’s and 1600’s, doctors and scientists made important advances in pharmacology (the study of drugs) and in other fields of science. These advances laid the foundation for later revolutionary progress in the development of drugs. In the early 1500’s, Swiss physician Philippus Paracelsus pioneered in the use of minerals as drugs. He introduced many compounds of lead, mercury, and other minerals in the treatment of diseases. But further progress in the development of drugs required advances in knowledge of the structure and functioning of the human body.

In 1543, the Flemish physician Andreas Vesalius, known as the founder of human anatomy, published the first complete description of the body’s structure. His work destroyed many false beliefs about human anatomy. In the early 1600’s, the English physician William Harvey discovered how blood—pumped by the heart—circulates through the body. Later in the 1600’s, Anton van Leeuwenhoek, an amateur Dutch scientist, discovered bacteria. He used crude microscopes to study the tiny organisms. But the role of germs as a cause of disease was not established until the 1800’s.

The drug revolution

began about 1800 and has continued to the present. During this period, scientists have discovered hundreds of drugs. They have also discovered the cause of many diseases, determined how drugs work, and learned much about how the body functions. In the process, the practice of medicine has been revolutionized, in large part by the use of drugs. Pharmacology has developed into a major science, and the manufacture of drugs has become a large industry.

In 1796, Edward Jenner, an English physician, developed the first successful vaccination in an effort to prevent the deadly disease smallpox. He vaccinated a boy with pus from blisters on a woman infected with cowpox. The boy then caught cowpox, a minor disease related to smallpox. Jenner later injected smallpox matter into the boy. But the boy did not catch smallpox because his fight with cowpox had made his body immune (resistant) to smallpox. Jenner’s discovery led to a search for vaccines against other diseases. This search gradually developed into the science of immunology.

Scientists learned how to isolate (separate) drugs from plants during the early 1800’s. In 1806, morphine became the first of the plant drugs to be isolated. Within a few years, scientists had also isolated quinine.

In the 1840’s, the use of anesthetics during surgery was introduced by two Americans working independently of each other—Crawford Long, a physician, and William T. G. Morton, a dentist. Later in the 1800’s, the French scientist Louis Pasteur and the German physician Robert Koch established the germ theory of disease. Pasteur proved that germs cause infectious diseases and that killing the germs responsible stopped the spread of such diseases. Koch developed a method for determining which bacteria cause particular diseases.

The pace of the drug revolution quickened in the 1900’s. In fact, most of the major drugs used today have been discovered since 1900. Important developments in hormone research followed the first isolation of a hormone in 1898. That year, an American pharmacologist, John J. Abel, isolated the hormone epinephrine, also called adrenalin. Scientists isolated several other hormones during the next 20 years. Then in the early 1920’s, a research team led by Frederick Banting, a Canadian physician, discovered the hormone insulin. Since then, this drug has saved the lives of millions of diabetics.

In the early 1900’s, Paul Ehrlich, a German scientist, developed a new method of treating infectious diseases. This method, called chemotherapy, involves the use of chemicals that attack disease-causing organisms. It is also used to destroy cancer cells. Ehrlich announced the discovery of the first chemotherapeutic drug, arsphenamine (Salvarsan), in 1910. His work led to the later discovery of the germ-fighting antibiotics and sulfa drugs.

The first antibiotic, penicillin, was discovered in 1928 by British scientist Alexander Fleming. A German physician, Gerhard Domagk, discovered the first sulfa drug, Prontosil, in 1935. Scientists soon developed other antibiotics and sulfa drugs. These “wonder drugs” were remarkably effective against many infectious diseases.

Many other important drugs have been discovered since 1900. Barbiturates, which reduce the activity of the nervous system and the muscles, were introduced in 1903. Amphetamines, which stimulate the nervous system, were first used medically in the early 1930’s. Scientists developed several important tranquilizers in the 1950’s, and birth control pills appeared in 1960. Scientists first used recombinant DNA techniques during the 1970’s. These techniques involve inserting human genes into bacterial cells or, occasionally, animal cells, causing the cells to produce human proteins. In the 1980’s, researchers applied recombinant DNA technology to produce large quantities of such drugs as insulin and interferon.

Scientists have also developed methods of using genetically identical cells to produce monoclonal antibodies that attack specific molecules. In addition, researchers are investigating gene therapy, using the nucleic acids DNA and RNA, to correct the way diseased cells work in the patient’s own body.

Growth of the drug industry.

Until about 1800, there were few drug companies. Pharmacists themselves made almost all the drugs they sold. Then two revolutions, one in drugs and the other in industrial development, gave birth to the modern drug industry. The discovery of more and more drugs that required special training and equipment to produce made it increasingly difficult for a pharmacist to prepare drugs. At the same time, the Industrial Revolution in Europe led to the development of manufacturing methods that could be used to mass-produce drugs. As a result, many drug companies were established in Europe, and European firms dominated the world drug market for many years.

The beginning of the United States drug industry can be traced back to the Revolutionary War in America (1775-1783). The chief pharmacist of the American army, Andrew Craigie, set up a laboratory in Carlisle, Pennsylvania, to supply drugs to the military. After the war, Craigie opened his own laboratory and began a wholesale drug business. Soon other pharmacists set up drug companies. These companies grew as they adopted the mass-production techniques developed in Europe.

The American Civil War (1861-1865)—like the Revolutionary War—created a great demand for drugs and so furthered the growth of the U.S. pharmaceutical industry. But European companies continued to dominate the world drug market until World War I (1914-1918). Before the war, the United States imported most of its drugs from Germany. But such imports stopped when the United States joined the war against Germany in 1917. The American pharmaceutical industry then expanded rapidly to meet the country’s drug needs. The United States soon began to export drugs and became one of the world’s leading producers. Today, the United States leads all countries in drug production.

Drugs today

benefit us tremendously. They also present us with some of our worst problems and greatest challenges. Drugs help prevent or control many diseases. They relieve pain and tension and help the body function properly. But misuse of alcohol, narcotics, and other drugs has led to addiction for millions of people. In addition, widespread illegal use of drugs has become a major problem. The challenges that drugs offer lie in the discovery of better medicines for treating cancer, cardiovascular diseases, AIDS, and other disabling and deadly disorders. In the 1980’s and 1990’s, pharmaceutical researchers increased efforts to find such drugs. Someday, scientists may develop drugs that lengthen life by slowing the aging process.