Summary Clinical Pharmacology Made Incredibly Easy.

Clinical Pharmacology Made Incredibly Easy. Fundamentals of clinical pharmacology Just the facts In this chapter, you’ll learn: pharmacology basics routes by which drugs are administered key concepts of pharmacokinetics key concepts of pharmacodynamics key concepts of pharmacotherapeutics key types of drug interactions and adverse reactions. Pharmacology basics This chapter focuses on the fundamental principles of pharmacology. It discusses basic information, such as how drugs are named and how they’re created. It also discusses the different routes by which drugs can be administered. Kinetics, dynamics, therapeutics This chapter also discusses what happens when a drug enters the body. This involves three main areas: pharmacokinetics (the absorption, distribution, metabolism, and excretion of a drug) pharmacodynamics (the biochemical and physical effects of drugs and the mechanisms of drug actions) pharmacotherapeutics (the use of drugs to prevent and treat diseases). In addition, the chapter provides an introduction to drug interactions and adverse drug reactions. What’s in a name? Drugs have a specific kind of nomenclature’that is, a drug can go by three different names: The chemical name is a scientific name that precisely describes its atomic and molecular structure. The generic, or nonproprietary, name is an abbreviation of the chemical name. The trade name (also known as the brand name or proprietary name) is selected by the drug company selling the product. Trade names are protected by copyright. The symbol ® after the trade name indicates that the name is registered by and restricted to the drug manufacturer. To avoid confusion, it’s best to use a drug’s generic name because any one drug can have a number of trade names. In 1962, the federal government mandated the use of official names so that only one official name would represent each drug. The official names are listed in the United States Pharmacopeia and National Formulary. Family ties Drugs that share similar characteristics are grouped together as a pharmacologic class (or family). betaadrenergic blockers are an example of a pharmacologic class. The therapeutic class groups drugs by therapeutic use. Antihypertensives are an example of a therapeutic class. Where drugs come from Traditionally, drugs were derived from natural sources, such as: plants animals minerals. Today, however, laboratory researchers use traditional knowledge, along with chemical science, to develop synthetic drug sources. One advantage of chemically developed drugs is that they’re free from the impurities found in natural substances. In addition, researchers and drug developers can manipulate the molecular structure of substances such as antibiotics so that a slight change in the chemical structure makes the drug effective against different organisms. The first-, second-, third-, and fourthgeneration cephalosporins are an example. Old-fashioned medicine The earliest drug concoctions from plants used everything: the leaves, roots, bulb, stem, seeds, buds, and blossoms. Subsequently, harmful substances often found their way into the mixture. As the understanding of plants as drug sources became more sophisticated, researchers sought to isolate and intensify active components while avoiding harmful ones. Power plant The active components consist of several types and vary in character and effect: Alkaloids, the most active component in plants, react with acids to form a salt that can dissolve more readily in body fluids. The names of alkaloids and their salts usually end in “-ine.” Examples include atropine, caffeine, and nicotine. Glycosides are also active components found in plants. Names of glycosides usually end in “-in” such as digoxin. Gums constitute another group of active components. Gums give products the ability to attract and hold water. Examples include seaweed extractions and seeds with starch. Resins, of which the chief source is pine tree sap, commonly act as local irritants or as laxatives. Oils, thick and sometimes greasy liquids, are classified as volatile or fixed. Examples of volatile oils, which readily evaporate, include peppermint, spearmint, and juniper. Fixed oils, which aren’t easily evaporated, include castor oil and olive oil. Animal magnetism The body fluids or glands of animals can also be drug sources. The drugs obtained from animal sources include: hormones such as insulin oils and fats (usually fixed) such as cod-liver oil enzymes, which are produced by living cells and act as catalysts, such as pancreatin and pepsin vaccines, which are suspensions of killed, modified, or attenuated microorganisms. (See Old McDonald had a pharm, page 4.) Mineral springs Metallic and nonmetallic minerals provide various inorganic materials not available from plants or animals. The mineral sources are used as they occur in nature or are combined with other ingredients. Examples of drugs that contain minerals are iron, iodine, and Epsom salts. Down to DNA Today, most drugs are produced in laboratories and can be: natural (from animal, plant, or mineral sources) synthetic. Old McDonald had a pharm In the near future, traditional barnyard animals might also be small, organic pharmaceutical factories. Some animals have already been genetically altered to produce pharmaceuticals, and their products are being tested by the Food and Drug Administration. Here are a few examples of the possibilities: a cow that produces milk containing lactoferrin, which can be used to treat human infections a goat that produces milk containing antithrombin III, which can help prevent blood clotting in humans a sheep that produces milk containing alpha1 - antitrypsin, which is used to treat cystic fibrosis. Examples of drugs produced in the laboratory include thyroid hormone (natural) and ranitidine (synthetic). Recombinant deoxyribonucleic acid research has led to other chemical sources of organic compounds. For example, the reordering of genetic information has enabled scientists to develop bacteria that produce insulin for humans. How drugs are administered A drug’s administration route influences the quantity given and the rate at which the drug is absorbed and distributed. These variables affect the drug’s action and the patient’s response. Routes of administration include: buccal, sublingual, translingual: certain drugs are given buccally (in the pouch between the cheek and gum), sublingually (under the tongue), or translingually (on the tongue) to speed their absorption or to prevent their destruction or transformation in the stomach or small intestine gastric: this route allows direct instillation of medication into the GI system of patients who can’t ingest the drug orally intradermal: substances are injected into the skin (dermis); this route is used mainly for diagnostic purposes when testing for allergies or tuberculosis intramuscular: this route allows drugs to be injected directly into various muscle groups at varying tissue depths; it’s used to give aqueous suspensions and solutions in oil, immunizations, and medications that aren’t available in oral form Streaming in intravenous: the I.V. route allows injection of substances (drugs, fluids, blood or blood products, and diagnostic contrast agents) directly into the bloodstream through a vein; administration can range from a single dose to an ongoing infusion delivered with great precision oral: this is usually the safest, most convenient, and least expensive route; drugs are administered to patients who are conscious and can swallow rectal and vaginal: suppositories, ointments, creams, gels, and tablets may be instilled into the rectum or vagina to treat local irritation or infection; some drugs applied to the mucosa of the rectum or vagina can be absorbed systemically respiratory: drugs that are available as gases can be administered into the respiratory system; drugs given by inhalation are rapidly absorbed, and medications given by such devices as the metereddose inhaler can be self-administered, or drugs can be administered directly into the lungs through an endotracheal tube in emergency situations.