DRUGS
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| Drugs approval Process in the Medical Field |
| I | INTRODUCTION |
Drug, substance that affects the function of living
cells, used in medicine to diagnose, cure, prevent the occurrence of diseases
and disorders, and prolong the life of patients with incurable conditions.
The availability of new and more effective
drugs, such as antibiotics, which fight bacterial infections, and vaccines,
which prevent diseases caused by bacteria and viruses, helped increase the
average American’s life span from about 60 years in 1900 to about 78 years in
2005. Drugs have vastly improved the quality of life. During the 20th
century, drugs enabled the eradication of smallpox, once a widespread and often
fatal disease. By the early 21st century, vaccines had led to the
near eradication of poliomyelitis, once feared as a cause of paralysis.
| II | CLASSIFICATION OF DRUGS |
Drugs can be classified in many ways: by the
way they are dispensed——over the counter or by prescription; by the substance
from which they are derived—plant, mineral, or animal; by the form they
take—capsule, liquid, or gas; and by the way they are administered—by mouth,
injection, inhalation, or direct application to the skin (absorption). Drugs are
also classified by their names. All drugs have three names: (1) a chemical name,
which describes the exact structure of the drug; (2) a generic or proprietary
name, which is the official medical name, assigned in the United States by the
U.S. Adopted Name Council (a group composed of pharmacists and other
scientists); and (3) a brand, or trade, name, given by the particular
manufacturer that sells the drug. If a company holds the patent on a drug—that
is, if the company has the exclusive right to make and sell a drug—then the drug
is available under one brand name only. After the patent expires, typically
after 17 years in the United States, other companies can also manufacture the
drug and market it under the generic name, or give it a new brand name.
Another way to categorize drugs is by the
way they act against diseases or disorders: chemotherapeutic drugs attack
specific organisms that cause a disease without harming the host, while
pharmocodynamic drugs alter the function of bodily systems by stimulating or
depressing normal cell activity in a given system. The most common way to
categorize a drug is by its effect on a particular area of the body or a
particular condition.
| A | Endocrine Drugs |
Endocrine drugs correct the overproduction
or underproduction of the body’s natural hormones. For example, insulin is a
hormone used as a drug to treat diabetes. Another example of endocrine drugs are
birth control pills, which contain the female sex hormones estrogen and
progesterone.
| B | Drugs that Fight Infections |
Anti-infective drugs are classified as
antibacterials, antivirals, or antifungals depending on the type of
microorganism they combat. Anti-infective drugs interfere selectively with the
functioning of a microorganism while leaving the human host unharmed.
Antibacterial drugs, or antibiotics—sulfa
drugs, penicillins, cephalosporins, and many others—either kill bacteria
directly or prevent them from multiplying so that the body’s immune system can
destroy invading bacteria. Antibacterial drugs act by interfering with some
specific characteristics of bacteria. For example, they may destroy bacterial
cell walls or interfere with the synthesis of bacterial proteins or
deoxyribonucleic acid (DNA)—the chemical that carries the genetic material of an
organism. Antibiotics often cure an infection completely. However, bacteria can
spontaneously mutate, producing strains that are resistant to existing
antibiotics.
Antiviral drugs interfere with the life
cycle of a virus by preventing its penetration into a host cell or by blocking
the synthesis of new viruses. Antiviral drugs may cure, but often only suppress,
viral infections; and flare-ups of an infection can occur after symptom-free
periods. With some viruses, such as human immunodeficiency virus (HIV), which
causes acquired immunodeficiency syndrome (AIDS), antiviral drugs can only
prolong life, not cure the disease.
Vaccines are used as antiviral drugs
against diseases such like mumps, measles, smallpox, poliomyelitis, and
influenza. Vaccines are made from either live, weakened viruses or killed
viruses, both of which are designed to stimulate the immune system to produce
antibodies, proteins that attack foreign substances. These antibodies protect
the body from future infections by viruses of the same type (see
Immunization).
Antifungal drugs selectively destroy fungal
cells by altering cell walls. The cells’ contents leak out and the cells die.
Antifungal drugs can cure, or may only suppress, a fungal infection.
| C | Cardiovascular Drugs |
Cardiovascular drugs affect the heart and
blood vessels and are divided into categories according to function.
Antihypertensive drugs reduce blood pressure by dilating blood vessels and
reducing the amount of blood pumped by the heart into the vascular system.
Antiarrhythmic drugs normalize irregular heartbeats and prevent cardiac
malfunction and arrest.
| D | Drugs that Affect the Blood |
Antianemic drugs, such as certain vitamins
or iron, enhance the formation of red blood cells. Anticoagulants like heparin
reduce blood-clot formation and ensure free blood flow through major organs in
the body. Thrombolytic drugs dissolve blood clots, which can block blood vessels
and deprive the heart or brain of blood and oxygen, possibly leading to heart
attack or stroke.
| E | Central Nervous System Drugs |
Central nervous system drugs—that is, drugs
that affect the spinal cord and the brain—are used to treat several neurological
(nervous system) and psychiatric problems. For instance, antiepileptic drugs
reduce the activity of overexcited brain areas and reduce or eliminate
seizures.
Antipsychotic drugs are used to regulate
certain brain chemicals called neurotransmitters, which do not function properly
in people with psychoses, major mental disorders often characterized by extreme
behaviors and hallucinations, such as in schizophrenia. Antipsychotic drugs can
often significantly alleviate hallucinations and other abnormal behaviors.
Antidepressant drugs reduce mental
depression. Antimanic drugs reduce excessive mood swings in people with bipolar
disorder (also called manic-depressive illness), which is characterized by
behavioral fluctuations between highs of extreme excitement and activity and
lows of lethargy and depression. Both types of drugs act by normalizing chemical
activity in the emotional centers of the brain. Antianxiety drugs, also referred
to as tranquilizers, treat anxiety by decreasing the activity in the anxiety
centers of the brain.
Sedative-hypnotic drugs are used both as
sedatives to reduce anxiety and as hypnotics to induce sleep. Sedative-hypnotic
drugs act by reducing brain-cell activity. Stimulant drugs, on the other hand,
increase neuronal (nerve cell) activity and reduce fatigue and appetite.
Analgesic drugs reduce pain and are
generally categorized as narcotics and non-narcotics. Narcotic analgesics, also
known as opioids, include opium and the natural opium derivatives codeine and
morphine; synthetic derivatives of morphine, such as heroin (the use of which is
illegal in the United States); and synthetic drugs such as meperidine and
propoxyphene hydrochloride. Narcotics relieve pain by acting on specific
structures, called receptors, located on the nerve cells of the spinal cord or
brain. Non-narcotic analgesics such as aspirin, acetaminophen, and ibuprofen
reduce pain by inhibiting the formation of nerve impulses at the site of pain.
Some of these drugs can also reduce fever and inflammation.
General anesthetics, used for surgery or
painful procedures, depress brain activity, causing a loss of sensation
throughout the body and unconsciousness. Local anesthetics are directly applied
to or injected in a specific area of the body, causing a loss of sensation
without unconsciousness; they prevent nerves from transmitting impulses
signaling pain (see Anesthesia).
| F | Anticancer Drugs |
Anticancer drugs eliminate some cancers or
reduce rapid growth and spread. These drugs do not affect all cancers but are
specific for cancers in certain tissues or organs such as the bladder, brain,
liver, or bones. Anticancer drugs interfere with specific cancer-cell
components. For example, alkylating agents are cytotoxic (cell-poisoning) drugs
that alter the DNA of cancer cells. Vinca alkaloids, chemicals produced by the
periwinkle plant, prevent cancer cell division.
| G | Other Drugs |
Many other categories of drugs also exist,
such as anti-inflammatory, antiallergic, antiParkinson (see Parkinson
Disease), antiworm (see Anthelmintic Drugs), diuretic, gastrointestinal,
pulmonary, and muscle-relaxant drugs. Often a drug in one category can also be
used for problems in other categories. For example, lidocaine can be used as a
local anesthetic or as a cardiac drug.
| III | HOW DRUGS MOVE THROUGH THE BODY |
The effect of a drug on the body depends on
a number of processes that the drug undergoes as it moves through the body. All
these processes together are known as pharmacokinetics (literally,
“motion of the drug”). First in these processes is the administration of the
drug after which it must be absorbed into the bloodstream. From the bloodstream,
the drug is distributed throughout the body to various tissues and organs. As
the drug is metabolized, or broken down and used by the body, it goes through
chemical changes that produce metabolites, or altered forms of the drug, most of
which have no effect on the body. Finally, the drug and its metabolites are
eliminated from the body.
| A | Administration |
Depending on the drug and its desired
effect, there are a variety of administration methods. Most drugs are
administered orally—that is, through the mouth. Only drugs that will not be
destroyed by the digestive processes of the stomach or intestines can be given
orally. Drugs can also be administered by injection into a vein (intravenously),
which assures quick distribution through the bloodstream and a rapid effect;
under the skin (subcutaneously) into the tissues, which results in localized
action at a particular site as with local anesthetics; or into a muscle
(intramuscularly), which enables rapid absorption through the many blood vessels
found in muscles. An intramuscular injection may also be given as a depot
preparation, in which the drug is combined with other substances so that it
is slowly released into the blood.
Inhaled drugs are designed to act in the
nose or lungs. General anesthetics may be given through inhalation. Some drugs
are administered through drug-filled patches that stick to the skin. The drug is
slowly released from the patch and enters the body through the skin. Drugs may
be administered topically—that is, applied directly to the skin; or
rectally—absorbed through an enema (an injection of liquid into the rectum) or a
rectal suppository (a pellet of medication that melts when inserted in the
rectum).
| B | Absorption |
Absorption is the transfer of a drug from
its site of administration to the bloodstream. Drugs that are inhaled or
injected enter the bloodstream more quickly than drugs taken orally. Oral drugs
are absorbed by the stomach or small intestine and then passed through the liver
before entering the bloodstream.
| C | Distribution |
Distribution is the transport of a drug
from the bloodstream to tissue sites where it will be effective, as well as to
sites where the drug may be stored, metabolized, or eliminated from the body.
Once a drug reaches its intended destination, the drug molecules move from blood
through cellular barriers to various tissues. These barriers include the walls
of blood vessels, the walls of the intestines, the walls of the kidneys, and the
special barrier between the brain and the bloodstream that acts as a filtration
system to protect the brain from exposure to potentially harmful
substances.
The drug molecules move from an area of
high drug concentration—the bloodstream—to an area of low drug concentration—the
tissues—until a balance between the two areas is reached. This process is known
as diffusion. When a drug reaches its highest concentration in the tissues, the
body begins to eliminate the drug and its effect on the body begins to diminish.
The time it takes for the level of a drug to fall by 50 percent is known as the
drug’s half-life. Depending on the drug, this measurement can vary from a few
minutes to hours or even days. For example, if a drug’s highest concentration
level in the blood is 1 mg/ml and this level falls to 0.5 mg/ml after five
hours, the half-life of the drug is five hours. A drug’s half-life is used to
determine frequency of dosage and the amount of drug administered.
Distribution of a drug may be delayed by
the binding of the drug to proteins in the blood. Because the proteins are too
large to pass through blood vessel walls, the drug remains in the blood for a
longer period until it is eventually released from the proteins. While this
process may increase the amount of time the drug is active in the body, it may
decrease the amount of the drug available to the tissues.
| D | Metabolism and Elimination |
While circulating through the body, a
drug undergoes chemical changes as it is broken down in a process called
metabolism, or biotransformation. Most of these changes occur in the liver, but
they can take place in other tissues as well. Various enzymes oxidize (add
oxygen to), reduce (remove oxygen from), or hydrolyze (add water to) the drug.
These changes produce new chemicals or metabolites that may continue to be
medically active in the body or may have no activity at all. A drug may be
broken down into many different metabolites. Eventually, most drugs or their
metabolites circulate through the kidney, where they are discharged, or
eliminated, into the urine. Drugs can also be excreted in the body’s solid waste
products, or evaporated through perspiration or the breath.
| E | Dose-Response Relationship |
The extent of the body’s response to a
drug depends on the amount administered, called the dose. At a low dose, no
response may be apparent. A higher dose, however, may produce the desired
effect. An even higher dose may produce an undesirable or harmful response. For
example, to relieve a headache most adults require two tablets of aspirin. A
half tablet may provide no relief from pain while ten tablets may cause burning
pain in the stomach or nausea.
The doses prescribed by physicians are
those recommended by each drug’s manufacturer to produce the best therapeutic,
or medically beneficial, responses in the majority of patients. However, doses
may need to be adjusted in certain individuals. For example, a person may be
born without the enzyme required to metabolize a particular drug while other
individuals may suffer from lung disorders that prevent them from absorbing
inhaled drugs. Factors such as alcohol consumption, age, the method of drug
administration, and whether or not the individual has taken the drug previously
can affect an individual’s response to a drug.
| F | Receptors |
Drugs interact with cell receptors, small
parts of proteins that control a multitude of chemical reactions and functions
in the body. Receptors have a specific, chemical structure compatible only with
certain drugs or endogenous compounds—substances that originate within the body
such as hormones and neurotransmitters. This relationship can be compared to
that of a lock and key: A drug molecule—the “key”—attaches briefly to its
specific receptor—the “lock” that only this molecule can open. The lock-and-key
combination of the drug and receptor results in a cascade of chemical events.
The extent of the response is determined by the number of receptors activated.
Stimulation of only a few receptors may not produce a response while stimulation
of a certain number of receptors is needed to produce the desired effect.
| IV | THERAPEUTIC RESPONSES AND ADVERSE REACTIONS |
The same receptors can be found in different
tissues and organs in the body, but receptors produce different responses
depending on their location. As a result, a specific drug can affect the body in
more than one way. Desirable effects are called therapeutic or beneficial
responses. Undesirable or harmful effects are called adverse reactions. Some
adverse reactions, or side effects, can be predicted. The most common side
effects are drowsiness, headache, sleeplessness, nausea, and diarrhea. Other
reactions, such as those that occur only in specific individuals for unexpected
reasons, called idiosyncratic reactions, and those that occur with the
triggering of the body’s immune system, called allergic reactions, are less
predictable.
Drug toxicity, or poisoning, can occur when
drugs are given in too large a dose or when individuals take a particular drug
over a long period of time—the drug may build up to dangerous levels in the
kidneys and liver and damage these organs. For some drugs, such as those used to
treat epilepsy, the difference between therapeutic and toxic concentrations is
small. Physicians constantly monitor the precise levels of such drugs in an
individual’s bloodstream to prevent drug poisoning.
Other drugs, such as those used to treat
cancer, are known to have toxic effects; however, the benefits outweigh the
risks—that is, treatment without them may result in death.
| A | Drug Interactions |
When taken together, drugs can interact
with one another and produce desirable or undesirable results. Some drugs have
an additive effect—that is, they increase the effect of other drugs. For
example, alcoholic beverages intensify the drowsiness-producing effect of some
sedatives. Other drugs have a reducing effect—that is, they interfere with the
action of drugs already present in the body. For example, antacids prevent
antibiotics from being absorbed by the stomach. Some drugs combine with other
drugs to create a substance that has no medical benefit. In some cases, however,
drug interactions can produce desirable results. Doctors have found that using
three drugs to fight AIDS is more effective than using one drug alone.
Drugs are most effective when properly
prescribed by physicians and taken correctly by patients. Missing doses, taking
drugs at the wrong time of the day or with instead of before meals, and stopping
drug use too soon can markedly reduce the medical benefits of many drugs.
| V | DRUG ABUSE |
Drug abuse is characterized by taking more
than the recommended dose of prescription drugs such as barbiturates without
medical supervision, or using government-controlled substances such as
marijuana, cocaine, heroin, or other illegal substances. Legal substances, such
as alcohol and nicotine, are also abused by many people. Abuse of drugs and
other substances can lead to physical and psychological dependence (see
Drug Dependence).
Drug abuse can cause a wide variety of
adverse physical reactions. Long-term drug use may damage the heart, liver, and
brain. Drug abusers may suffer from malnutrition if they habitually forget to
eat, cannot afford to buy food, or eat foods lacking the proper vitamins and
minerals. Individuals who abuse injectable drugs risk contracting infections
such as hepatitis and HIV from dirty needles or needles shared with other
infected abusers. One of the most dangerous effects of illegal drug use is the
potential for overdosing—that is, taking too large or too strong a dose for the
body’s systems to handle. A drug overdose may cause an individual to lose
consciousness and to breathe inadequately. Without treatment, an individual may
die from a drug overdose.
Drug addiction is marked by a compulsive
craving for a substance. Successful treatment methods vary and include
psychological counseling, or psychotherapy, and detoxification
programs—medically supervised programs that gradually wean an individual from a
drug over a period of days or weeks. Detoxification and psychotherapy are often
used together.
The illegal use of drugs was once considered
a problem unique to residents of poor, urban neighborhoods. Today, however,
people from all economic levels, in both cities and suburbs, abuse drugs. Some
people use drugs to relieve stress and to forget about their problems. Genetic
factors may predispose other individuals to drug addiction. Environmental
factors such as peer pressure, especially in young people, and the availability
of drugs, also influence people to abuse drugs.
| VI | HISTORY |
Humans have always experimented with
substances derived from minerals, plants, and animal parts to treat pain,
illness, and restore health. In ancient Egypt, physicians prescribed figs,
dates, and castor oil as laxatives and used tannic acid to treat burns. The
early Chinese and Greek pharmacies included opium, known for its pain-relieving
qualities, while Hindus used the cannabis and henbane plants as anesthetics and
the root of the plant Rauwolfia serpentina, which contains reserpine, as
a tranquilizer.
A school of pharmacy established in Arabia
from 750 to 1258 ad discovered
many substances effective against illness, such as burned sponge (which contains
iodine) for the treatment of goiters—a noncancerous enlargement of the thyroid
gland, visible as a swelling at the front of the neck. In Europe, the 15th
century Swiss physician and chemist Philippus Aureolus Paracelsus identified the
characteristics of numerous diseases such as syphilis, a chronic infectious
disease usually transmitted in sexual intercourse, and used ingredients such as
sulfur and mercury compounds to counter the diseases.
During the 17th and 18th centuries,
physicians treated malaria, a disease transmitted by the bite of an infected
mosquito, with the bark of the cinchona tree (which contains quinine). Heart
failure was treated with the leaves of the foxglove plant (which contains
digitalis); scurvy, a disease caused by vitamin C deficiency, was treated with
citrus fruit (which contains vitamin C); and smallpox was prevented using
inoculations of cells infected with a similar viral disease known as cowpox. The
therapy developed for smallpox stimulated the body’s immune system, which
defends against disease-causing agents, to produce cowpox- and smallpox-specific
antibodies.
In the 19th century scientists continued to
discover new drugs including ether, morphine, and a vaccine for rabies, an
infectious, often fatal, viral disease of mammals that attacks the central
nervous system and is transmitted by the bite of infected animals. These
substances, however, were limited to those occurring naturally in plants,
minerals, and animals. A growing understanding of chemistry soon changed the way
drugs were developed. Heroin and aspirin, two of the first synthetic drugs
created from other elements or compounds using chemical reactions, were produced
in the late 1800s. This development, combined with the establishment of a new
discipline called pharmacology, the study of drugs and their actions on the
body, signaled the birth of the modern drug industry.
| VII | DRUG DEVELOPMENT |
Today most drugs are synthesized by
chemists in the laboratory. Synthetic drugs are better controlled than those
occurring naturally, which ensures that each dose imparts the same effect. Some
new synthetic drugs are developed by modifying the structure of existing
substances. These new drugs are called analogues. For example, prednisone is an
analogue of the hormone cortisone (see Hydrocortisone). Because
scientists can selectively alter the drug’s structure, analogues may be more
effective and cause fewer side effects than the drugs from which they were
derived.
One of the newer methods for developing
drugs involves the use of gene splicing, or recombinant DNA (see Genetic
Engineering). In drug research, this technique joins the DNA of a specific type
of human cell to the DNA of a second organism, usually a harmless bacterium, to
produce a recombinant (or “recombined”) DNA. The altered organism then begins to
produce the substance produced by the human cell. This substance is extracted
from the bacteria and purified for use as a drug.
The first drug produced in this manner was
the hormone insulin in 1982, which was created in large quantities by inserting
the human insulin gene in Escherichia coli (E. coli) bacteria.
This recombinant insulin has largely replaced versions of the drug extracted
from pig and cattle pancreases. Since 1982 other genetically engineered drugs
for humans have been developed, including tissue plasminogen activator (tPA), an
enzyme used to dissolve blood clots in people who have suffered heart attacks,
and erythropoetin, a hormone used to stimulate the production of red blood cells
in people with severe anemia.
Because of the great expense and time
involved, most new drugs are created by large, well-funded pharmaceutical
companies. From idea to production, the development of a new drug can take up to
ten years and cost about $200 million. The process usually starts with the idea
that an existing chemical substance has therapeutic value or that the structure
of an existing drug can be modified for new clinical uses. Out of 10,000
chemicals tested in a laboratory, only one may eventually become a drug.
Once drug researchers have determined that
a new substance may have medical value, an elaborate testing program begins. The
drug is tested first on small animals such as rats and mice, and then on larger
animals such as monkeys and dogs. If these tests indicate that the new drug is
effective against its intended target—such as a particular disease—and shows an
acceptably low level of toxicity, the drug company requests government
permission to test the drug in humans. In the United States, the Food and Drug
Administration (FDA), an agency of the U.S. Department of Health and Human
Services, grants or denies these requests.
If the agency approves the request,
clinical trials on humans can begin. These experiments are usually divided into
three phases, each of which can last from several months to several years. In
the first phase, the drug is tested on a small number of healthy individuals to
determine its effect on the body. The second phase tests the drug on a small
number of people who have the disease or disorder the drug manufacturer hopes
the drug will treat. These individuals are divided into two groups: those who
receive the drug and those who receive a placebo, or inactive compound. Neither
the investigating physicians nor the members of the test group know who is
receiving the drug or who is receiving the placebo. This technique, called a
double-blind study, ensures that no one consciously or unconsciously influence
the drug’s effect. The third phase tests the drug on a much larger group of
people and determines specific doses, possible interactions with other drugs,
responses related to gender, and other information used for drug labeling. At
the end of the third phase, a drug manufacturer compiles the results of the
clinical trials and submits them to the FDA in a new product application. If the
drug has been proven effective and safe, and its benefits outweigh any risks,
the agency approves the drug for marketing. FDA approval of a new drug may take
up to 18 months; however, the agency is working to reduce the time to 12 months
for most drugs and 6 months for highly effective drugs that treat previously
incurable conditions.
| VIII | DRUG REGULATION |
Because drugs can produce harmful effects
when manufactured or taken improperly, most governments control drug development
as well as availability. In the United States, the FDA determines how drugs are
produced and how they are sold. Drugs that can be sold over the counter
(OTC)—that is, without a prescription from a physician—are called proprietary
drugs. They are considered safe for unsupervised use by the general population.
Drugs that must be prescribed by physicians and dispensed by pharmacists are
known as ethical drugs. Their use is monitored closely by medical
personnel.
The FDA regulates the sale and manufacture
of drugs in the United States as outlined in applicable laws enacted over the
past century. Legal standards for composition and preparation of drugs in the
United States are found in the publication known as the United States
Pharmacopeia (USP). Drugs that can be abused, such as the powerful narcotic
heroin, are regulated by the Drug Enforcement Administration (DEA) of the U.S.
Department of Justice to ensure that they are not prescribed or sold
illegally.
Before 1900 any individual could sell a
drug and claim it offered therapeutic benefits without medical proof. This
changed after 1906 with the passage of the Pure Food and Drug Act, which
required drug manufacturers to state the content, strength, and purity of each
drug they produced. The Pure Food and Drug Act ended the practice of including
morphine, cocaine, and heroin in drugs without the public’s knowledge. In 1914
the U.S. legislature began to strictly regulate the trade of narcotics with the
enactment of the Harrison Narcotic Act; in 1937 the government added marijuana
to this list of controlled substances (the Marijuana Tax Act).
The Federal Food, Drug, and Cosmetic Act
was enacted in 1938 requiring that new drugs be safe for humans; however, it did
not require that manufacturers prove their drugs’ effectiveness. It would be 24
years before legislation was passed that would require proof of the efficacy of
new drugs (the Kefaver-Harris Amendments, 1962). Enforcement of this law was
entrusted to the FDA.
Two laws enacted in the 1960s strengthened
the FDA’s efforts to reduce drug abuse. The Drug Abuse Control Amendments of
1965 provided penalties for the illegal sale or possession of stimulants,
sedatives, and hallucinogens, and the Narcotic Addict Rehabilitation Act of 1966
set up a federal program for addicts that provided them with the option of
receiving treatment for their drug problems in place of a prison sentence.
In 1970 the Comprehensive Drug Abuse
Prevention and Control Act established rules for manufacturing and prescribing
habit-forming drugs. It stipulated that physicians can prescribe all drugs, but
a special license is required to prescribe drugs with a high abuse potential.
This license is issued by the Drug Enforcement Administration.
The Anti-Drug Abuse Acts, signed into law
in 1986 and 1988, set up funding for the treatment of drug abuse and for the
creation of law-enforcement programs to fight the illegal sale of drugs. These
acts also detailed severe punishments for individuals selling and possessing
drugs illegally. Harsh penalties for using anabolic steroids (hormones that
promote the storage of protein and the growth of tissue that are sometimes
abused by competitive athletes) were included in the 1988 act, along with the
requirement that all alcoholic beverages be labeled with warnings about
alcohol’s potentially dangerous effect on the body. The 1988 act also
established the Office of National Drug Control Policy to develop an action plan
that would involve the public, as well as private agencies, in eliminating the
illegal sale of drugs; in helping individuals who use drugs to stop; and in
preventing nonusers from ever starting to use drugs.
The U.S. government and its regulatory
agencies continually monitor the development and use of all drugs sold in the
United States to ensure that the American public has access only to drugs that
are safe and effective. Sometimes, adverse reactions to a drug come to light
after it has been approved by the FDA and used by large numbers of patients. For
example, the analgesic Vioxx was approved in 1999, but in 2004 the FDA asked the
drug’s maker to remove it from the market because it had been linked to heart
attacks and strokes.
Smoking kills!
| I | INTRODUCTION |
Smoking, inhalation and exhalation of the fumes of
burning tobacco. Leaves of the tobacco plant are smoked in various ways. After a
drying and curing process, they may be rolled into cigars or shredded for
insertion into smoking pipes. Cigarettes, the most popular method of smoking,
consist of finely shredded tobacco rolled in lightweight paper. About 46 million
people in the United States smoke an estimated 420 billion cigarettes each year.
Until the 1940s smoking was considered
harmless, but laboratory and clinical research has since confirmed that tobacco
smoke presents a hazard to health. Smoke from the average cigarette contains
around 4,000 chemicals, some of which are highly toxic and at least 43 of which
cause cancer. Nicotine, a major constituent of tobacco smoke, is both poisonous
and highly addictive. According to the American Cancer Society, smoking is the
most preventable cause of death in America today.
| II | HISTORY |
European explorers who arrived in the Western
Hemisphere in the 1500s observed Native Americans smoking tobacco plant leaves
in pipes. The colonists who followed them grew tobacco plants as a cash crop for
export, and smoking became part of European culture by the 1600s. Most tobacco
was consumed in pipes and cigars or as snuff (finely pulverized tobacco
inhaled into the nostrils). This pattern changed by the early 20th century, by
which time smokers consumed more than 1,000 cigarettes per capita each year in
the United States and some European countries. The general attitude of society
was that smoking relieved tension and produced no ill effects. During World War
II (1939-1945) American physicians endorsed sending soldiers tobacco, and
cigarettes were included in the field ration kits of U.S. armed forces personnel
until 1975.
Some scientists noticed, however, that lung
cancer, which was rare before the 20th century, had increased dramatically since
about 1930. The American Cancer Society and other organizations initiated
studies comparing deaths among smokers and nonsmokers over a period of several
years. All such studies found increased mortality among smokers, both from
cancer and other causes. In addition, experimental studies in animals showed
that many of the chemicals contained in cigarette smoke are carcinogenic.
In 1962 the U.S. government appointed a panel
of ten scientists to study the available evidence concerning the health effects
of smoking. Their conclusions were included in the 1964 surgeon general’s
report, which stated that “cigarette smoking is a health hazard of sufficient
importance in the United States to warrant appropriate remedial action.” Smoking
in adults, measured as an average number of cigarettes smoked per year, began to
decline steadily after the 1964 report and has fallen more than 40 percent since
1965.
| III | HEALTH EFFECTS OF SMOKING |
 |
| Chronic Bronchitis and Ephysema |
About 442,000 people in the United States
die each year from illnesses caused by cigarette smoking. Smoking accounts for
nearly 90 percent of lung cancer deaths. Additionally, smokers are at increased
risk for cancer of the larynx, oral cavity, esophagus, bladder, kidney, and
pancreas. While some negative health effects of smoking manifest slowly over
time, others can be measured almost immediately. Sticky brown tar leaves yellow
stains on fingers and teeth. Some of the inhaled tar is absorbed by lung cells,
causing them to die. Tar also damages the cilia in the upper airways that
protect against infection. Nicotine causes arteries to constrict, lowering skin
temperature and reducing blood flow to the hands and feet. Carbon monoxide
deprives the body of oxygen, binding to red blood cells in place of the oxygen
molecule and forcing the heart to pump more blood through the body.
One-third of smoking-related deaths are
caused by coronary heart disease or chronic airway obstruction. For example, the
nicotine in tobacco combines with carbon monoxide in tobacco smoke to damage the
lining of blood vessels and make blood platelets stickier. Platelets form part
of the damaging plaque buildup in artery walls (see Arteriosclerosis).
These effects in combination contribute to the development of heart disease.
Smoking also increases the risk of stroke by 50 percent—40 percent among men and
60 percent among women. Other research has shown that mothers who smoke give
birth more frequently to premature or underweight babies, probably because of a
decrease in blood flow to the placenta. Babies born to mothers who smoke during
pregnancy are also at increased risk for sudden infant death syndrome.
Cigar and pipe smoke contains the same toxic
and carcinogenic compounds found in cigarette smoke. A report by the National
Cancer Institute concluded that the mortality rates from cancer of the mouth,
throat, larynx, pharynx, and esophagus are approximately equal in users of
cigarettes, cigars, and pipes. Rates of coronary heart disease, lung cancer,
emphysema, and chronic bronchitis are elevated for cigar and pipe smokers and
are correlated to the amount of smoking and the degree of inhalation.
Studies have found that cigarettes are
addictive because an unknown component of tobacco smoke appears to destroy an
important brain enzyme known as monoamine oxidase B (MAO B). The enzyme is vital
for breaking down excess amounts of dopamine, a neurotransmitter that triggers
pleasure-seeking behavior. Smokers have decreased levels of MAO B and abnormally
high levels of dopamine, which may encourage the smoker to seek the pleasure of
more tobacco smoke.
Even nonsmokers are at risk from smoking.
Recent research has focused on the effects of environmental tobacco smoke
(ETS)—that is, the effect of tobacco smoke on nonsmokers who must share the same
environment with a smoker. The United States Environmental Protection Agency
(EPA) estimates that exposure to ETS, which contains all the toxic agents
inhaled by a smoker, causes 3,000 lung cancer deaths and an estimated 35,000
deaths from heart disease per year among nonsmokers. Secondhand smoke can
aggravate asthma, pneumonia, and bronchitis, and impair blood circulation.
The smoking habit and addiction to nicotine
usually begin at an early age. In the United States, more than 90 percent of
adults who smoke started by age 21, and nearly half of them were regular smokers
by the age of 18. Despite increasing warnings about the health hazards of
smoking and widespread bans on smoking in public places, smoking remains common
among teenagers and young adults. In 2001 surveys of students in grades 9
through 12 found that more than 38 percent of male students and nearly 30
percent of female students smoke. Although black teenagers have the lowest
smoking rates of any racial group, cigarette smoking among black teens increased
80 percent in the late 1990s. Advertisements aimed at a young audience are
largely blamed for this new generation of smokers.
| IV | QUITTING SMOKING |
Studies of former smokers show that their
risk of dying from smoking-related disease decreases with each year of
abstinence. According to the World Health Organization (WHO), smokers who quit
smoking before the age of 50 reduce their risk of life-threatening disease by
half after just one year, compared with those who continue smoking.
Other benefits of quitting smoking include
more disposable income, admission to social activities and institutions that ban
smoking, and often, lower health insurance premiums. Nonetheless, to quit
smoking is difficult, most likely because smokers crave the effect of the
nicotine in the smoke. The U.S. surgeon general declared nicotine an addictive
drug comparable to other addictive substances, including cocaine, heroin, and
alcohol, in its ability to induce dependence. Overall, tobacco smoking causes
about 20 times the number of deaths in the United States than all other
addictive drugs combined.
Smoking cessation methods are plentiful, and
many books and products are available to help an individual stop smoking. Many
smokers turn to group help because of the support and understanding provided by
other former smokers or people trying to quit. Most successful group-help
techniques involve a challenge and reward system that also bolsters the
self-discipline of the former smoker.
A number of nicotine replacement products are
available to help a person quit smoking. Nicotine patches are small,
nicotine-containing adhesive disks that must be applied to the skin. The
nicotine is slowly absorbed through the skin and enters the bloodstream. Over
time, a smoker uses nicotine patches containing smaller and smaller doses of
nicotine until eventually the craving for nicotine ends. Nicotine gum works in a
similar manner, providing small doses of nicotine when chewed. A nicotine nasal
spray is a physician-prescribed spray that relieves cravings for a cigarette by
delivering nicotine to the nasal membranes. Also available by prescription, the
nicotine inhaler looks like a cigarette; when puffed, the inhaler releases
nicotine into the mouth.
An approach combining three different smoking
cessation therapies has found remarkable success. This approach combines an
antidepressant drug called bupropin, marketed under the brand name Zyban, with a
nicotine replacement product and counseling. While less than 25 percent of
smokers who use nicotine replacement products alone remain smoke-free for more
than a year, 40 to 60 percent of smokers using this combination approach
achieved this milestone.
| V | ANTISMOKING ACTION IN SOCIETY |
In the United States, the first direct action
to curb smoking after the U.S. surgeon general’s 1964 report on smoking was the
mandate of a warning on cigarette packages by the Federal Trade Commission. This
warning took effect in 1964 and was strengthened in 1969 to read: “Warning: The
Surgeon General Has Determined That Cigarette Smoking Is Dangerous to Your
Health.” A stronger sequence of four alternative warnings was developed in 1984.
In 1971 all cigarette advertising was banned from radio and television, and
cities and states passed laws requiring nonsmoking sections in public places and
workplaces.
This trend has continued and smoking is now
banned at the federal and state levels in most government buildings and in many
private businesses. As of February 1990 federal law banned smoking on all
domestic United States airline flights under six hours in duration. By 1998 more
than 90 percent of nonstop flights between the United States and all foreign
countries were also smoke free.
In 2002 President George W. Bush signed into
law the Safe and Drug-Free Schools and Communities Act. The law bans smoking
within any indoor facility used for childhood education. By 2003 a number of
states (including New York, Connecticut, Maine, and California) and cities
(including Boston, Massachusetts and Austin, Texas) passed laws banning smoking
in all bars, restaurants, and clubs. Several European countries also began to
ban smoking in public places—especially in restaurants, bars, and cafes. They
include Ireland, Italy, Netherlands, and Norway. A ban in the United Kingdom is
scheduled to take effect in 2007; a ban in France, in 2008.
The tobacco industry has been increasingly
criticized for its role in encouraging smoking, particularly in young people.
Various lawsuits have been brought against tobacco companies to reclaim damages
due to disease or death associated with smoking. The first major successful suit
occurred in March 1996 when the Liggett Group, a consortium of companies, agreed
to pay damages to five states. An onslaught of litigation against the tobacco
industry followed. In part to avoid potentially ruinous lawsuits filed by
states, in 1998 the tobacco industry and attorneys general from 46 U.S. states
agreed to a $206-billion settlement. The settlement, to be paid over 25 years,
will be used to compensate states for the costs of treating smoking-related
illness, to finance nationwide antismoking programs, and to underwrite health
care for uninsured children.
The tobacco industry must also contend with a
barrage of lawsuits filed by individual smokers and their families seeking
damages for smoking-related health problems and deaths. Across the United
States, such lawsuits have had mixed results. In several cases, juries have
cleared the tobacco companies of all responsibility. While several other cases
have resulted in large awards for the plaintiffs, few hold up under the appeals
process.
Tobacco industry representatives long denied
that nicotine is addictive and that there is a link between smoking and poor
health. In recent years, however, cigarette makers have faced increased pressure
from smoking-related lawsuits and federal regulators to accept prevailing
scientific opinions about the health risks of smoking. In late 1999 Philip
Morris, now known as Altria, the nation’s largest cigarette maker, publicly
acknowledged that smoking is addictive and causes serious health problems. This
latest admission was considered a way to make it more difficult for those who
have recently started smoking to claim they were unaware of the dangers if they
choose to sue cigarette companies. In 2003 an Illinois judge ordered Philip
Morris to pay $10.1 billion in damages for using misleading advertising
campaigns suggesting that cigarette brands marketed as “low tar” or “light” are
safer than regular brands. Numerous scientific studies prove that the use of
low-tar cigarettes does not reduce the risk of developing smoking-related
disease, and the judge found that Philip Morris intentionally disregarded
consumer rights by spreading disinformation.
