Introduction To Pharmacology PDF

PHARMACOLOGY FOR NURSES A Pathophysiologic Approach FIFTH EDITION Chapter 1&2 Introduction to Pharmacology...

PHARMACOLOGY FOR NURSES A Pathophysiologic Approach FIFTH EDITION Chapter 1&2 Introduction to Pharmacology Fatima Awwad Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Pharmacology Simply defined, from the Greek, as the study of medicine Pharmacology is an expansive subject encompassing: How drugs are administered Where drugs travel in the body Responses that drugs produce Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Interrelated Subject Areas Anatomy and physiology Chemistry Microbiology Pathophysiology Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Pharmacology Is Challenging and Always Changing 10,000 drugs currently available Each drug has its own characteristics: Therapeutic applications Interactions Adverse effects Mechanisms of action Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Pharmacology Is Challenging and Always Changing Many drugs prescribed for more than one disease Drugs elicit different responses depending on individual factors: Age Sex Body mass Health status Genetics Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Nursing and Pharmacology Knowledge of pharmacology essential to the nursing profession Nurses are health care providers most often directly involved in patient care Applies to nurses in all settings from clinics and hospitals to home care Applies to nurses who teach and to students entering nursing profession Study of pharmacology is gradual process that continues throughout life Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Therapeutics and Pharmacology Are Closely Connected Therapeutics is concerned with Prevention of disease Treatment of suffering Pharmacotherapy is the application of drugs for Disease treatment Alleviation of suffering Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Therapeutic agents: Therapeutic agents may be classified as drugs, biologics, or complementary and alternative medicine (CAM) therapies: Traditional drugs are chemical agents: Synthesized in a laboratory. Produce biological responses in the body If desirable response—therapeutic If undesirable response—adverse After a drug is administered, it is called a medication Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Biologics Biologics are agents naturally produced in animal cells, by microorganisms, or by the body itself. Examples: Hormones Monoclonal antibodies Natural blood products and components Interferons Vaccines Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Complementary and Alternative Therapies Natural plant extracts, herbs, vitamins, minerals, dietary supplements Physical therapy, manipulations, massage, acupuncture, hypnosis, biofeedback Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Drug Are Organized in Two Ways: Therapeutic classification: Based on therapeutic usefulness in treating particular diseases or disorders. Ex: Antidepressants. Pharmacologic classification: Based on the way a drug works at the molecular, tissue, or body system level. Ex: Diuretics Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Table 1.1 Therapeutic Classification Table 1.1 Therapeutic Classification FOCUS: CARDIOVASCULAR FUNCTION Usefulness Drug Classification Influence blood clotting Anticoagulant Lower blood cholesterol Antihyperlipidemic Lower blood pressure Antihypertensive Restore normal cardiac rhythm Antidysrhythmic Treat angina Antianginal Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Table 1.2 Pharmacologic Classification Table 1.2 Pharmacologic Classification FOCUSING ON THERAPEUTIC APPLICATION: PHARMACOTHERAPY FOR HYPERTENSION Mechanism of Action Drug Classification Lowers plasma volume Diuretic Blocks heart calcium channels Calcium channel blocker Blocks hormonal activity Angiotensin-converting enzyme Inhibitor Blocks physiological reactions to stress Adrenergic antagonist Dilates peripheral blood vessels Vasodilator Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  “Prototype” Drug: serves as model for a drug class: Is well understood Has known action and adverse effects Is used to compare other drugs in the same pharmacologic class May not be the most widely used drug in its class Disagreements may exist over which drug should serve as prototype drug Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Newer Drugs in the Same Class: Newer drugs in the same class may replace the prototype drug because they: – Are more effective – Have a more favorable safety profile – Have longer duration of action Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Most drugs have three names: 1. Chemical name: drug has one chemical name, often complicated, and difficult to remember or pronounce. Ex: Chemical name for diazepam: 7-chloro-1, 3-dihydro-1-methyl-5- phenyl-2H-1, 4-benzodiazepin-2-one 2. Generic name: each drug has one generic name, less complicated and easier to remember. Ex: Ibuprofen 3. Trade name: a drug has several trade names, assigned by company marketing the drug, short, easy to remember, also called proprietary, product, or brand name. Ex: Trufen, Ibufen, Advil. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Drug Has One Chemical Name Assigned using standard nomenclature established by International Union of Pure and Applied Chemistry (IUPAC) Describes physical and chemical properties of drug Sometimes helpful in predicting a substance's physical and chemical properties Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Each Drug Has One Generic Name Used by many organizations – U.S. Food and Drug Administration (FDA) – U.S. Pharmacopoeia – World Health Organization (WHO) Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Trade Names Trade names can be difficult because many drugs contain similar ingredients – Combination drug contains more than one active generic ingredient – Rule of thumb is that active ingredients in a drug are described by their generic name, which is lowercase Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Table 1.3 Examples of Trade-Name Products Containing Popular Generic Substances Table 1.3 Examples of Trade-Name Products Containing Popular Generic Substances Generic Substance Trade Names aspirin Acuprin, Anacin, Aspergum, Bayer, Bufferin, Ecotrin, Empirin, Excedrin, Maprin, Norgesic, Salatin, Salocol, Salsprin, Supac, Talwin, Triaphen-10, Vanquish, Verin, Zorprin diphenhydramine Allerdryl, Benadryl, Benahist, Bendylate, Caladryl, Compoz, Diahist, Diphenadril, Eldadryl, Fenylhist, Fynex, Hydramine, Hydril, Insomnal, Noradryl, Nordryl, Nytol, Tusstat, Wehdryl ibuprofen Advil, Amersol, Apsifen, Brufen, Haltran, Medipren, Midol 200, Motrin, Neuvil, Novoprofen, Nuprin, Pamprin-IB, Rufen, Trendar Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Prescription Drugs and OTC Drugs Prescription drugs require that the recipient obtain a written order from a person with the legal authority to write such a prescription. OTC drugs: over the counter drugs. Prescription: written direction for preparation and administration of a drug Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Advantages and Disadvantages of Prescription Drugs Advantages: Health care provider or nurse practitioner examines the patient, determines a specific diagnosis, and orders the proper drug Amount and frequency of drug is controlled Instructions on use and side effects of drug are discussed Disadvantages: Require a prescription to obtain Need for health care provider appointment Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Advantages and Disadvantages of OTC Drugs Advantages: No health care provider appointment required Often less expensive than prescription drugs Disadvantages: Patient may choose wrong drug Patient may not know reactions or interactions Ineffective treatment may result in progression of disease Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Chapter 2 Drug Approval and Regulation Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Prior to 19th Century Few standards or guidelines to protect the public – Some drugs contained hazardous levels of Dangerous substances Addictive substances Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Early Drug References The first standard commonly used by pharmacists was the formulary, or list of drugs and drug recipes A pharmacopoeia is a comprehensive medical reference summarizing and publishing drug standards Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  United States Pharmacopoeia (USP), 1820 First comprehensive publication of drug standards Summarized standards of drug: – Purity – Strength – Directions for synthesis Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Drug regulation were created to protect the public from drug misuse and to assume continuous evaluation of safety and effectiveness. The regulatory agency responsible for ensuring that drugs and medical devices are safe and effective is the Food and Drug Administration (FDA). Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Once criticized for being too slow, the FDA has streamlined the process to get new drugs to market more quickly. Center for Drug Evaluation and Research (CDER): is a branch of FDA, determines safety and efficacy of drugs. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Black Box Warnings Black Box Warnings: One of the primary alerts for identifying extreme adverse drug reactions discovered during and after the review process. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Four Stages of Approval for Therapeutic and Biologic Drugs: 1. Preclinical investigation 2. Clinical investigation 3. Review of new drug application (NDA) 4. Postmarketing surveillance Nurses may participate in several phases of the drug approval process but will have the most frequent opportunities during Phase 4, postmarketing surveillance. Medication safety is a matter of paramount importance in health care. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Figure 2.3 A new drug development time line with the four phases of drug approval Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Preclinical Investigation Involves laboratory research Tests done on cells and animals Determines drug-dose range Examines adverse effects Results considered inconclusive Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  FDA Critical Path Initiative In 2007, FDA restated its concern that a number of innovative and critical medical products had decreased since the 1990s – Critical Path Initiative was initiated to modernize the sciences to enhance the use of bioinformation to improve the safety, effectiveness, and manufacturability of candidate medical products Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Clinical Investigation Takes place in three different stages termed clinical phase trials Longest part of approval process Evaluates human benefits Tests on healthy humans first, then on those with the target ailment Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Review of New Drug Application (NDA) If results of clinical investigation are positive, even if precautions are noted, a New Drug Application (NDA) is next step NDA is third step of drug approval process Average review time 17–24 months Drug approved: process continues Drug rejected: process suspended Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Investigational New Drug Application (IND) May be submitted for Phase I clinical trials when it is determined there are significant therapeutic benefits, and the product is reasonably safe for initial use in humans Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Postmarketing Surveillance New drug placed on market Surveyed for harmful effects in larger population – Diabetes drug troglitazone (Rezulin) is an example of a drug that did not exhibit harmful effects until the year after release – COX-2 selective nonsteroidal anti-inflammatory drugs celecoxib (Celebrex) still being analyzed after others in its group were withdrawn Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Postmarketing Surveillance FDA holds annual public meetings – Will withdraw a drug if serious problem found Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Nurses and the Drug Approval Process Nurses participate most in the drug approval process during the postmarketing surveillance period of Phase IV All nurses administering medications monitor for therapeutic effects and adverse reactions from the drugs Responsible for reporting adverse reactions Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Effects of Drugs Therapeutic effect = desired effect – Reason drug is prescribed Side effect = secondary effect – Unintended, usually predictable – May be harmless or harmful Adverse effect – More severe side effect – May justify discontinuation of a drug Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Effects of Drugs (cont'd) Drug toxicity:Results from overdose, ingestion of external- use drug, or buildup of drug in blood Drug allergy: Immunologic reaction to drug Mild to severe reactions (anaphylactic reaction, anaphylaxis) A mild reaction has a variety of symptoms, from skin rashes to diarrhea (Pruritus (itching), Angioedema (Swelling), dyspnea) Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Effects of Drugs (cont'd) Anaphylactic reaction, Anaphylaxis: The earliest symptoms are a subjective feeling of swelling in the mouth and tongue, acute shortness of breath, acute hypotension, and tachycardia. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Effects of Drugs (cont'd) Drug tolerance – Unusually low physiological response – Requires increases in the dosage to maintain a given therapeutic effect – Cumulative effect – Increased effect resulting from rate of dosage being higher than rate of excretion – Idiosyncratic( ‫ )مميز‬effect – Unexpected; may be individual to client Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Effects of Drugs (cont'd) Drug interaction – One drug alters effect of one or both drugs Potentiating effect - one or both drugs is increased – Additive – two of same types of drugs increase action of each other – Synergistic –two different drugs increase action of one or another Inhibiting effect – Effect of one or both drugs is decreased Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Drug Misuse Improper use of common medications Drug abuse: is the inappropriate intake of a substance. Drug abuse has two main facets: Drug dependence – Psychological dependence:Few signs of physical discomfort when drug is withdrawn, but intense compelling desire to continue drug use. – is emotional reliance on a drug to maintain a sense of well- being, accompanied by feelings of need or cravings for that drug. (may be mild or sever…..) Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Physical dependence / Physiological dependence: is due to biochemical changes in body tissues, especially the nervous system. An altered physical condition caused by the adaptation of the nervous system to repeated drug use When the drug is no longer available, the individual expresses physical signs of discomfort known as withdrawal Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Addiction: the overwhelming feeling that drives someone to use a drug repeatedly. Drugs with a potential for abuse are restricted by the Controlled Substances Act and are categorized into five schedules. Schedule I drugs are the most tightly controlled ex: Heroin; Schedule V drugs have less potential for addiction and are less tightly controlled ex: OTC cough medicines with codeine. Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Controlled Substances Controlled substances are drugs that: – Are restricted by the Controlled Substances Act of 1970 and later revisions – Are frequently abused – Have a high potential for addiction or dependence – Have restricted use – Are placed into one of five schedules Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Table 2.1 U.S. Drug Schedules and Examples Table 2.1 U.S. Drug Schedules and Examples Potential for Potential for Drug Abuse Physical Psychological Schedule Potential Dependency Dependency Examples Therapeutic Use I Highest High High heroin, lysergic acid diethylamide (LSD), Limited or no marijuana (cannabis), peyote, methaqualone, therapeutic use and 3, 4-methylenedioxymethamphetamine (“ecstasy”) II High High High hydromorphone, methadone, meperidine, oxycodone, and fentanyl; amphetamine, methamphetamine, methylphenidate, cocaine, amobarbital, glutethimide, and pentobarbital III Moderate Moderate High combination products containing less than 15 Used therapeutically mg of hydrocodone per dosage unit, products with prescription; some containing not more than 90 mg of codeine per drugs no longer used dosage unit, buprenorphine products, (Schedules II, III and IV) benzphetamine, phendimetrazine, ketamine, and anabolic steroids IV Lower Lower Lower alprazolam, clonazepam, clorazepate, diazepam, lorazepam, midazolam, temazepam, and triazolam V Lowest Lowest Lowest cough preparations containing not more than Used therapeutically 200 mg of codeine per 100 mL or per 100 g without prescription Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved  Teratogenic Drug Classification Five categories of risk that a drug poses to a fetus in the case of a pregnant woman taking the drug A, B, C, D, and X Copyright © 2017, 2014, 2011 Pearson Education, Inc. All Rights Reserved