$Unique_ID{BRK03005} $Pretitle{} $Title{The New Prescription Drug Reference Guide - How Drugs Work} $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 ------------------------------------------------------------------------------ Prescription drugs fall into a number of groups according to the conditions for which they are prescribed. In the following pages, we will provide you with a better understanding of the types of medications that are prescribed for different medical conditions. We'll describe the intended actions of drugs and the therapeutic effects you can expect from various types of medications. CARDIOVASCULAR DRUGS Antianginals Since the heart is a muscle that must work continuously, it requires a constant supply of nutrients and oxygen. The chest pain known as angina can occur when there is an insufficient supply of blood, and consequently of oxygen, to the heart. There are several types of antianginal drugs. These drugs include vasodilators (nitroglycerin, isosorbide dinitrate), calcium channel blockers (diltiazem, nifedipine, verapamil), and beta blockers (acebutolol, atenolol, labetalol, metoprolol, nadolol, pindolol, propranolol, timolol). All of these drugs act by increasing the amount of oxygen that reaches the heart muscle. Antiarrhythmics If the heart does not beat rhythmically or smoothly (a condition called arrhythmia), its rate of contraction must be regulated. Antiarrhythmic drugs (disopyramide, mexiletine, procainamide, propranolol, tocainide, quinidine) prevent or alleviate cardiac arrhythmias by altering nerve impulses within the heart. Antihypertensives Briefly, high blood pressure is a condition in which the pressure of the blood against the walls of the blood vessels is higher than what is considered normal. High blood pressure, or hypertension, which can eventually cause damage to the brain, eyes, heart, or kidneys, is controllable. If a medication for high blood pressure has been prescribed, it is very important that you continue to take it regularly, even if you don't notice any symptoms of hypertension. If hypertension is controlled, other damage can be prevented. Drugs that counteract or reduce high blood pressure can prolong a hypertensive patient's life. Several different drug actions produce an antihypertensive effect. Some drugs block nerve impulses that cause arteries to constrict; others slow the heart rate and decrease its force of contraction; still others reduce the amount of a certain hormone (aldosterone) in the blood that causes blood pressure to rise. The effect of any of these is to reduce blood pressure. The mainstay of antihypertensive therapy is often a diuretic, a drug that reduces body fluids. Examples of additional antihypertensive drugs include clonidine, hydralazine, methyldopa, prazosin, and reserpine. Diuretics Diuretic drugs, such as chlorothiazide, chlorthalidone, furosemide, hydrochlorothiazide, and spironolactone, promote the loss of water and salt from the body (this is why they are sometimes called "water pills"). This loss of water and salt results in lowering of blood pressure. They also lower blood pressure by increasing the diameter of blood vessels. Because many antihypertensive drugs cause the body to retain salt and water, they are often used concurrently with diuretics. Most diuretics act directly on the kidneys, but there are different types of diuretics, each with different actions. Thus, therapy for high blood pressure can be individualized for each patient's needs. Thiazide diuretics, such as chlorothiazide, chlorthalidone, and hydrochlorothiazide are the most commonly prescribed water pills available today. They are generally well tolerated and can be taken once or twice a day. Since patients do not develop a tolerance to their antihypertensive effect, they can be taken for prolonged periods. However, a major drawback to thiazide diuretics is that they often deplete the body of potassium. This depletion can be compensated for with a potassium supplement. Potassium-rich foods and liquids, such as bananas, apricots, and orange juice, can also be used to help correct the potassium deficiency. Salt substitutes are another source of potassium. Your doctor will direct you as to which source of potassium, if any, is appropriate for you to use. Loop diuretics, such as furosemide, act more vigorously than thiazide diuretics. (The term "loop" refers to the structures in the kidneys on which these medications act.) Loop diuretics promote more water loss but also deplete more potassium. To remove excess water from the body but retain its store of potassium, manufacturers developed potassium-sparing diuretics. Drugs such as spironolactone, triamterene, and amiloride are effective in treating potassium loss, heart failure, and hypertension. Potassium-sparing diuretics are combined with thiazide diuretics in medications such as spironolactone and hydrochlorothiazide combination, triamterene and hydrochlorothiazide combination, and amiloride and hydrochlorothiazide combination. Such combinations enhance the antihypertensive effect and reduce the loss of potassium. They are now among the most commonly used antihypertensive agents. Cardiac Glycosides Cardiac glycosides include drugs that are derived from digitalis (for example, digoxin and digitoxin). This type of drug slows the rate of the heart but increases its force of contraction. Cardiac glycosides, therefore, act as both heart depressants and stimulants and may be used to regulate irregular heart rhythm or to increase the volume of blood pumped by the heart in heart failure. Anticoagulants Drugs that prevent blood clotting are called anticoagulants (blood thinners). Anticoagulants fall into two categories. The first category contains only one drug, heparin. Heparin must be given by injection, so its use is generally restricted to hospitalized patients. The second category includes oral anticoagulants, principally derivatives of the drug warfarin. Warfarin may be used in the treatment of conditions such as stroke, heart disease, and abnormal blood clotting. It is also used to prevent the movement of a clot, which could cause serious problems. It acts by preventing the liver from manufacturing the proteins responsible for blood clot formation. Persons taking warfarin must avoid using many other drugs (including aspirin), because their interaction with the anticoagulant could cause internal bleeding. Patients taking warfarin should check with their pharmacist or physician before using any other medications, including over-the-counter products for coughs or colds. In addition, they must have their blood checked frequently by their physician to ensure that the drug is maintaining the correct degree of blood thinning. Antihyperlipidemics Drugs used to treat atherosclerosis (arteriosclerosis, or hardening of the arteries) act to reduce the serum (the liquified portion of blood) levels of cholesterol and triglycerides (fats), which form plaques (deposits) on the walls of arteries. Some antihyperlipidemics, such as cholestyramine and colestipol, bind to bile acids in the gastrointestinal tract, thereby decreasing the body's production of cholesterol. Clofibrate and probucol also decrease the body's production of cholesterol. Use of such drugs is generally recommended only after diet and lifestyle changes have failed to lower blood lipids to desirable levels. Even then, diet therapy should be continued. Vasodilators Vasodilating drugs cause the blood vessels to dilate (widen). Some of the antihypertensive agents, such as hydralazine and prazosin, lower blood pressure by dilating the arteries or veins. Other vasodilators are used in the treatment of stroke and diseases characterized by poor circulation. Ergoloid mesylates, for example, are used to reduce the symptoms of senility by increasing blood flow to the brain. Beta Blockers Beta-blocking drugs block the response of the heart and blood vessels to nerve stimulation, thereby slowing the heart rate and reducing high blood pressure. They are used in the treatment of a wide range of diseases including angina, hypertension, migraine headaches, and arrhythmias. Propranolol and metoprolol are two examples of beta blockers. Calcium Channel Blockers Calcium channel blockers (diltiazem, nifedipine, verapamil) are used for the prevention of angina (chest pain). Verapamil is also useful in correcting certain arrhythmias (heartbeat irregularities) and lowering blood pressure. This group of drugs is thought to prevent angina and arrhythmias by blocking or slowing calcium flow into muscle cells, which results in vasodilation (widening of the blood vessels) and greater oxygen delivery to the heart muscle. DRUGS FOR THE EARS For an ear infection, a physician usually prescribes an antibiotic and a steroid, or a medication that contains a combination of these. The antibiotic attacks the infecting bacteria, and the steroid reduces the inflammation and pain. Often, a local anesthetic, such as benzocaine or lidocaine, may also be prescribed to relieve pain. DRUGS FOR THE EYES Almost all drugs that are used to treat eye problems can be used to treat disorders of other parts of the body as well. Glaucoma is one of the major disorders of the eye, especially in people over 40 years of age, and results in increased pressure within the eyeball. Although glaucoma is sometimes treated surgically, pressure in the eye can usually be reduced, and blindness prevented, through use of eye drops. Two drugs frequently prescribed as eye drops are epinephrine and pilocarpine. Pilocarpine is a cholinergic drug. Cholinergic drugs act by stimulating parasympathetic nerve endings. Stimulation of these nerve endings alters the activity of many organs throughout the body. For example, a cholinergic drug can cause the heart rate to decrease, intestinal activity to increase, and the bronchioles within the lungs to constrict. When used in the eyes, pilocarpine causes constriction of the pupils and increases the flow of aqueous humor (fluid) out of the eye, thereby reducing the pressure. Epinephrine is a newer name for the body chemical called adrenaline. Epinephrine is secreted in the body when one must flee from danger, resist attack, or combat stress. Epinephrine has adrenergic properties, such as increasing the amount of sugar in the blood, accelerating the heartbeat, and dilating the pupils. The mechanism by which epinephrine lowers pressure within the eye is not completely understood, but it appears to involve both a decrease in the production of aqueous humor and an increase in the outflow of this fluid from the eye. Antibiotics are used to treat bacterial eye infections. Steroids can also be used to treat noninfectious eye inflammations, as long as these medications are not used for too long a period of time. Pharmacists carefully monitor requests for eye drop refills, particularly for drops that contain steroids, and may refuse to refill such medication until you have revisited your doctor because these products can cause further eye problems with long-term use. GASTROINTESTINAL DRUGS Antinauseants Antinauseants reduce the urge to vomit. One of the most effective antinauseants is the phenothiazine derivative prochlorperazine. This medication acts on the vomiting center in the brain. It is often administered rectally and usually alleviates nausea and vomiting within a few minutes to an hour. Antihistamines are also commonly used to prevent nausea and vomiting, especially when those symptoms are due to motion sickness. This type of medication may also work at the vomiting center in the brain. Anticholinergics Anticholinergic drugs--for example, dicyclomine--slow the action of the bowel and reduce the amount of stomach acid. Because these drugs slow the action of the bowel by relaxing the muscles and relieving spasms, they are said to have an antispasmodic action. Antiulcer Medications Antiulcer medications are prescribed to relieve symptoms and promote healing of peptic ulcers. The antisecretory ulcer medications cimetidine, famotidine, and ranitidine work by suppressing the production of excess stomach acid. Another antiulcer drug, sucralfate, works by forming a chemical barrier over an exposed ulcer (like a bandage) thereby protecting the ulcer from stomach acid. These drugs provide sustained relief from ulcer pain and promote healing. Antidiarrheals Diarrhea may be caused by many conditions, including influenza and ulcerative colitis, and can sometimes occur as a side effect of drug therapy. Narcotics and anticholinergics slow the action of the bowel and can thereby help alleviate diarrhea. A medication such as diphenoxylate and atropine contains both a narcotic and an anticholinergic. HORMONES A hormone is a substance produced and secreted by a gland. Hormones stimulate and regulate body functions. Hormone drugs are given to mimic the effects of naturally produced hormones. Hormone drugs are prescribed to treat various conditions. Most often, they are used to replace naturally occuring hormones that are not being produced in amounts sufficient to regulate specific body functions. This category of medication also includes oral contraceptives and certain types of drugs that are used to combat inflammatory reactions. Thyroid Drugs Thyroid hormone was one of the first hormone drugs to be produced synthetically. Originally, thyroid preparations were made by drying and pulverizing the thyroid glands of animals and then forming them into tablets. Such preparations are still used today in the treatment of patients who have reduced levels of thyroid hormone production. However, a synthetic thyroid hormone (levothyroxine) is also available. Antidiabetic Drugs Insulin, which is secreted by the pancreas, regulates the level of glucose (a form of sugar) in the blood, as well as the metabolism of carbohydrates and fats. Insulin's counterpart, glucagon, stimulates the liver to release stored glucose. Both insulin and glucagon must be present in the right amounts to maintain the proper blood sugar levels. Treatment of diabetes mellitus (the condition in which the body is unable to produce and/or utilize insulin) may involve an adjustment of diet and/or the administration of insulin or oral antidiabetic drugs. Glucagon is given only in emergencies (for example, insulin shock, when blood sugar levels must be raised quickly). Oral antidiabetic medications induce the pancreas to secrete more insulin by acting on small groups of cells within the pancreas that make and store insulin. Oral antidiabetic medications are prescribed for diabetic patients who are unable to regulate their blood sugar levels through diet modification alone. These medications cannot be used by patients who have insulin-dependent (juvenile-onset, or Type I) diabetes; their blood sugar levels can be controlled only with injections of insulin. Steroids The pituitary gland secretes adrenocorticotropic hormone (ACTH), which directs the adrenal glands to produce adrenocorticosteroids (for example, cortisone). Oral steroid preparations (for example, prednisone) may be used to treat inflammatory diseases such as arthritis or to treat poison ivy, hay fever, or insect bites. How these drugs relieve inflammation is currently unknown. Steroids may also be applied to the skin to treat certain inflammatory skin conditions. Triamcinolone and the combination of fluocinonide, hydrocortisone, and iodochlorhydroxyquin are examples of steroid hormone creams or ointments. 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.