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- $Unique_ID{BRK02991}
- $Pretitle{}
- $Title{The New Prescription Drug Reference Guide - How Drugs Work, part II}
- $Subject{Types CARDIOVASCULAR Antianginals Antiarrhythmics Antihypertensives
- Diuretics Cardiac Glycosides Anticoagulants Antihyperlipidemics Vasodilators
- Beta Blockers Calcium Channel Blockers EARS EYES GASTROINTESTINAL
- Antinauseants Anticholinergics Antiulcer Antidiarrheals HORMONES Thyroid
- Antidiabetic Steroids Sex Hormones ANTI-INFECTIVES Antibiotics Antivirals
- Vaccines anthelmintics pediculicide scabicide ANTINEOPLASTICS TOPICAL CENTRAL
- NERVOUS SYSTEM Sedatives Tranquilizers Antidepressants Amphetamines
- Anticonvulsants Antiparkinsonism Agents Analgesics Anti-Respiratory
- Antitussives Expectorants Decongestants Bronchodilators Antihistamines
- VITAMINS MINERALS}
- $Volume{}
- $Log{}
-
- Copyright (C) 1993 Publications International, Ltd.
-
-
- How Drugs Work, part II
- ------------------------------------------------------------------------------
-
- Sex Hormones
-
- Although the adrenal glands secrete small amounts of sex hormones, these
- hormones are produced mainly by the sex glands. Estrogens are the female
- hormones responsible for secondary sex characteristics such as development of
- the breasts and maintenance of the lining of the uterus. Testosterone
- (androgen) is the corresponding male hormone. It is responsible for secondary
- sex characteristics such as a beard, a deepened voice, and the maturation of
- external genitalia. Progesterone is also produced in females--it prepares the
- uterus for pregnancy.
- Testosterone reduces elimination of protein from the body, thereby
- producing an increase in muscle size. Athletes sometimes take drugs called
- anabolic steroids (chemicals similar to testosterone) for this effect, but
- such use of these drugs is dangerous. Anabolic steroids can adversely affect
- the heart, nervous system, and kidneys.
- Most oral contraceptives (birth control pills) combine estrogen and
- progesterone, but some contain only progesterone. The estrogen in birth
- control pills prevents egg production. Progesterone aids in preventing
- ovulation, alters the lining of the uterus, and thickens cervical
- mucus--processes that help to prevent conception and implantation. Oral
- contraceptives have many side effects, so their use should be discussed with a
- physician.
- Conjugated estrogens are used as replacement therapy to treat symptoms of
- menopause in women whose bodies are no longer producing sufficient amounts of
- estrogen. Medroxyprogesterone is used to treat uterine bleeding and menstrual
- problems. It prevents uterine bleeding by inducing and maintaining a lining
- in the uterus that resembles the lining produced during pregnancy. In
- addition, it suppresses the release of the pituitary gland hormone that
- initiates ovulation.
-
- ANTI-INFECTIVES
-
- Antibiotics
-
- Antibiotics are used to treat a wide variety of bacterial infections.
- They are usually derived from molds or are produced synthetically.
- Antibiotics inhibit the growth of bacteria by interfering with their
- production of certain biochemicals necessary to sustain life or by interfering
- with their ability to use nutrients. The body's defenses then have a much
- easier time eliminating the infection.
- When used properly, antibiotics are usually effective. To adequately
- treat an infection, antibiotics must be taken regularly for a specific period
- of time. If you do not take an antibiotic for the prescribed period,
- microorganisms resistant to the antibiotic are given the opportunity to
- continue growing, and your infection could recur. Aminoglycosides,
- cephalosporins, erythromycins, penicillins (including ampicillin and
- amoxicillin), and tetracyclines are some examples of antibiotics.
- Antibiotics do not counteract viruses, such as those causing the common
- cold, so their use in cold therapy is inappropriate.
-
- Antivirals
-
- Antiviral drugs are used to combat viral infections. An antiviral drug
- called acyclovir is being used in the management of herpes. Acyclovir reduces
- the reproduction of the herpes virus in initial outbreaks, lessens the number
- of recurring outbreaks, and speeds the healing of herpes blisters. However,
- this antiviral drug does not cure herpes.
-
- Vaccines
-
- Vaccines were used long before antibiotics became available. A vaccine
- contains weakened or dead disease-causing microorganisms or parts of such
- organisms, which activate the body's immune system to produce a natural
- defense against a particular disease (such as polio or measles). A vaccine
- may be used to alleviate or treat an infectious disease, but most commonly it
- is used to prevent a specific disease.
-
- Other Anti-infectives
-
- Drugs called anthelmintics are used to treat worm infestations. Fungal
- infections are treated with antifungals (such as nystatin)--drugs that destroy
- and prevent the growth of fungi.
- A pediculicide is a drug used to treat a person infested with lice, and a
- scabicide is a preparation used to treat a person with scabies.
-
- ANTINEOPLASTICS
-
- Antineoplastic drugs are used in the treatment of cancer. Most of the
- drugs in this category prevent the growth of rapidly dividing cells, such as
- cancer cells. Antineoplastics are, without exception, extremely toxic and can
- cause serious side effects. But for many cancer victims, the benefits derived
- from chemotherapy with antineoplastic drugs far outweigh the risks involved.
-
- TOPICAL DRUGS
-
- Drugs are often applied topically (locally to the skin) to treat skin
- disorders with minimal systemic (throughout the body) side effects.
- Antibiotic creams or ointments are used to treat skin infections, and
- adrenocorticosteroids are used to treat inflammatory skin conditions. Another
- common dermatologic (skin) problem is acne. Acne can be--and often
- is--treated with over-the-counter drugs, but it sometimes requires
- prescription medication. Antibiotics such as tetracycline, erythromycin, or
- clindamycin are used orally or applied topically to slow the growth of the
- bacteria that play a role in the formation of acne pustules. Keratolytics
- (agents that soften the skin and cause the outer cells to slough off) are also
- sometimes prescribed.
- Some drugs applied to the skin do have effects within the body. For
- example, nitroglycerin is absorbed into the bloodstream from ointment or
- patches placed on the skin. The absorbed nitroglycerin dilates blood vessels
- and prevents anginal pain. Clonidine, scopolamine, and estrogen are available
- as transdermal patches, also.
-
- CENTRAL NERVOUS SYSTEM DRUGS
-
- Sedatives
-
- Medications used in the treatment of anxiety or insomnia selectively
- reduce activity in the central nervous system (brain and spinal cord). Drugs
- that have a calming effect include barbiturates, chlordiazepoxide,
- clorazepate, diazepam, doxepin, hydroxyzine, meprobamate, and oxazepam. Drugs
- to induce sleep in insomniacs include butabarbital, flurazepam, temazepam, and
- triazolam.
-
- Tranquilizers
-
- Major tranquilizers or antipsychotic agents are usually prescribed for
- patients with psychoses (certain types of mental disorders). These drugs calm
- certain areas of the brain but permit the rest of the brain to function
- normally. They act as a screen that allows transmission of some nerve
- impulses but restricts others. The drugs most frequently used are
- phenothiazines, such as chlorpromazine and thioridazine. Haloperidol, a
- butyrophenone, has the same effect as chlorpromazine.
-
- Antidepressants
-
- Tricyclic antidepressants (such as amitriptyline), tetracyclic
- antidepressants (such as maprotiline), and monoamine oxidase (MAO) inhibitors
- (such as phenelzine) are used to combat depression. Antidepressants are also
- used in the preventive treatment of migraine headaches, although the manner in
- which they help these headaches is not clearly understood.
- Antidepressants may produce serious side effects, and they can interact
- with other drugs. MAO inhibitors can also interact with certain foods,
- resulting in dangerous increases in blood pressure. Therefore, they should be
- used very carefully.
-
- Amphetamines
-
- Amphetamines or adrenergic drugs are commonly used as anorectics (drugs
- used to reduce the appetite). These drugs temporarily quiet the part of the
- brain that causes hunger, but they also keep a person awake, speed up the
- heart, and raise blood pressure. After two to three weeks, these medications
- begin to lose their effectiveness as appetite suppressants.
- Amphetamines stimulate most people, but they have the opposite effect on
- hyperkinetic children. Hyperkinesis (the condition of being highly
- overactive) is difficult to diagnose or define and requires a specialist to
- treat. When hyperkinetic children take amphetamines or the adrenergic drug
- methylphenidate, their activity slows down. Most likely, amphetamines quiet
- these youngsters by selectively stimulating parts of the brain that ordinarily
- provide control of activity.
-
- Anticonvulsants
-
- Drugs such as phenytoin and phenobarbital are used to control seizures
- and other symptoms of epilepsy. They selectively reduce excessive stimulation
- in the brain.
-
- Antiparkinsonism Agents
-
- Parkinson's disease is a progressive disorder that is due to a chemical
- imbalance in the brain. Victims of Parkinson's disease have uncontrollable
- tremors, develop a characteristic stoop, and eventually become unable to walk.
- Drugs such as benztropine, trihexyphenidyl, levodopa, and bromocriptine are
- used to correct the chemical imbalance, thereby relieving the symptoms of the
- disease. Benztropine and trihexyphenidyl are also used to relieve tremors
- caused by other medications.
-
- Analgesics
-
- Pain is not a disease but a symptom. Drugs used to relieve pain are
- called analgesics. These drugs form a rather diverse group. We do not fully
- understand how most analgesics work. Whether they all act on the brain is not
- known. Analgesics fall into two categories; they may be either narcotic or
- nonnarcotic.
- Narcotics are derived from the opium poppy. They act on the brain to
- cause deep analgesia and often drowsiness. Some narcotics relieve coughing
- spasms and are used in many cough syrups. Narcotics relieve pain and give the
- patient a feeling of well-being. They are also addictive. Manufacturers have
- attempted to produce nonaddictive synthetic narcotic derivatives but have not
- yet been successful.
- Many nonnarcotic pain relievers are commonly used. Salicylates are the
- most commonly used pain relievers in the United States today. The most widely
- used salicylate is aspirin. While aspirin ordinarily does not require a
- prescription, many doctors may prescribe it to treat such diseases as
- arthritis.
- The aspirin substitute acetaminophen may be used in place of aspirin to
- relieve pain. It does not, however, reduce inflammation (such as that caused
- by arthritis).
- A number of analgesics contain codeine or other narcotics combined with
- nonnarcotic analgesics (such as aspirin or acetaminophen). These analgesics
- are not as potent as pure narcotics but are frequently as effective. Because
- these medications contain narcotics, they have potential for abuse and must be
- used with caution.
-
- Anti-inflammatory Drugs
-
- Inflammation is the body's response to injury. It causes swelling, pain,
- fever, redness, and itching. Aspirin is one of the most effective
- anti-inflammatory drugs. Other drugs, called nonsteroidal anti-inflammatory
- drugs (for example, fenoprofen, ibuprofen, indomethacin, naproxen, and
- tolmetin), relieve inflammation and may be more effective than aspirin in
- certain individuals. Steroids are also used to treat inflammatory diseases.
- When sore muscles tense, they cause pain, inflammation, and spasm.
- Skeletal muscle relaxants (for example, orphenadrine, aspirin, and caffeine
- combination; meprobamate and aspirin combination; and chlorzoxazone and
- acetaminophen combination) can relieve these symptoms. Skeletal muscle
- relaxants are often given in combination with an anti-inflammatory drug such
- as aspirin. Some doctors, however, believe that aspirin and rest are better
- for alleviating the pain and inflammation of muscle strain than are skeletal
- muscle relaxants.
-
- RESPIRATORY DRUGS
-
- Antitussives
-
- Antitussives control coughs. There are numerous over-the-counter
- (nonprescription) antitussives available--most of them contain
- dextromethorphan. Codeine is a narcotic antitussive that is an ingredient in
- many prescription cough medications. These cough syrups must be absorbed into
- the blood and must circulate and act on the brain before they relieve a cough.
-
- Expectorants
-
- Expectorants are used to change a nonproductive cough to a productive one
- (one that brings up phlegm). Expectorants are supposed to increase the amount
- of mucus produced. However, drinking water or using a vaporizer or humidifier
- is probably more effective in increasing mucus production. Popular
- expectorant ingredients include ammonium chloride, guaifenesin, potassium
- guaiacolsulfonate, and terpin hydrate.
-
- Decongestants
-
- Decongestants constrict blood vessels in the nose and sinuses to open up
- air passages. They are available as oral preparations, nose drops, and nose
- sprays. Oral decongestants are slow-acting but do not interfere with
- production of mucus or movement of the cilia (special hairlike structures) of
- the respiratory tract. They can, however, increase blood pressure, so they
- should be used cautiously by patients with high blood pressure. Topical
- decongestants (nose drops or spray) provide almost immediate relief. They do
- not increase blood pressure as much as oral decongestants, but they do slow
- the movement of the cilia.
- People who use these products may also develop a tolerance for them.
- Tolerance can be described as a need for ever-increasing dosages to achieve a
- beneficial effect. The additional disadvantage of developing tolerance is
- that the risk of side effects increases as the dosage increases. Topical
- decongestants should not be used for more than a few days at a time.
-
- Bronchodilators
-
- Bronchodilators (agents that open airways in the lungs) and agents that
- relax smooth-muscle tissue (such as that found in the lungs) are used to
- improve breathing. Theophylline and aminophylline are oral bronchodilators
- commonly used to relieve the symptoms of asthma and pulmonary emphysema.
- Albuterol and metaproterenol are inhalant bronchodilators, which act directly
- on the muscles of the bronchi (breathing tubes).
-
- Antihistamines
-
- Histamine is a body chemical that, when released in the body, typically
- causes swelling and itching. Antihistamines counteract these symptoms of
- allergy by blocking the effects of histamine. For mild respiratory allergies,
- such as hay fever, antihistamines can be used. Diphenhydramine and other
- antihistamines are relatively slow-acting. Severe allergic reactions
- sometimes require the use of epinephrine (which is not an antihistamine); in
- its injectable form, it is very fast-acting.
- Some types of antihistamines are also used to prevent or treat the
- symptoms of motion sickness. Diphenhydramine and meclizine are examples of
- drugs used specifically for this purpose.
-
- VITAMINS AND MINERALS
-
- Vitamins and minerals are chemical substances that are vital to the
- maintenance of normal body function. Most people obtain enough vitamins and
- minerals in their diet, but some people have vitamin deficiencies. Serious
- nutritional deficiencies lead to diseases such as pellagra and beriberi, which
- must be treated by a physician. People who have an inadequate or restricted
- diet, people who have certain disorders or debilitating illnesses, and women
- who are pregnant or breast-feeding are among those who may benefit from taking
- supplemental vitamins and minerals. However, even these people should consult
- a doctor to see if a true vitamin deficiency exists.
-
- ----------------
-
- The material contained here is "FOR INFORMATION ONLY" and should not replace
- the counsel and advice of your personal physician. Promptly consulting your
- doctor is the best path to a quick and successful resolution of any medical
- problem.
-