Comprehensive Pharmacy Review for NAPLEX 8th Edition PDF

 Comprehensive Pharmacy Review for NAPLEX Eighth Edition Shargel_8e_FM.indd i 07/09/12 6:05 PM Shargel_8e_FM.indd ii 07/09/12 6:05 PM  Comprehensive...

 Comprehensive Pharmacy Review for NAPLEX Eighth Edition Shargel_8e_FM.indd i 07/09/12 6:05 PM Shargel_8e_FM.indd ii 07/09/12 6:05 PM  Comprehensive Pharmacy Review for NAPLEX Eighth Edition EDITORS Leon Shargel, PhD, RPh Alan H. Mutnick, PharmD, FASHP, RPh Paul F. Souney, MS, RPh Larry N. Swanson, PharmD, FASHP, RPh Shargel_8e_FM.indd iii 07/09/12 6:05 PM  Acquisitions Editor: Sirkka Howes Product Manager: Michael Marino Marketing Manager: Joy Fisher-Williams Design Coordinator: Teresa Mallon Production Services: Absolute Service, Inc. Eighth Edition Copyright © 2013, 2010, 2007, 2004, 2001 by Lippincott Williams & Wilkins, a Wolters Kluwer business. 351 West Camden Street Two Commerce Square Baltimore, MD 21201 2001 Market Street Philadelphia, PA 19103 Printed in China All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. To request permission, please contact Lippincott Williams & Wilkins at Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103, via e-mail at [email protected], or via website at lww.com (products and services). 987654321 Library of Congress Cataloging-in-Publication Data Comprehensive pharmacy review for NAPLEX / editors, Leon Shargel... [et al.]. — 8th ed. p. ; cm. Comprehensive pharmacy review for North American Pharmacist Licensure Examination Includes index. Rev. ed. of: Comprehensive pharmacy review / editors, Leon Shargel... [et al.]. 7th ed. c2010. ISBN 978-1-4511-1704-2 (pbk.) I. Shargel, Leon, 1941- II. Comprehensive pharmacy review. III. Title: Comprehensive pharmacy review for North Ameri- can Pharmacist Licensure Examination. [DNLM: 1. Pharmacy—Examination Questions. QV 18.2] 615'.1076—dc23 2012020144 DISCLAIMER Care has been taken to confirm the accuracy of the information present and to describe generally accepted practices. However, the authors, editors, and publisher are not responsible for errors or omissions or for any consequences from appli- cation of the information in this book and make no warranty, expressed or implied, with respect to the currency, complete- ness, or accuracy of the contents of the publication. Application of this information in a particular situation remains the professional responsibility of the practitioner; the clinical treatments described and recommended may not be considered absolute and universal recommendations. The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with the current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new or infrequently employed drug. Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings. It is the responsibility of the health care provider to ascertain the FDA status of each drug or device planned for use in their clinical practice. To purchase additional copies of this book, call our customer service department at (800) 638-3030 or fax orders to (301) 223-2320. International customers should call (301) 223-2300. Visit Lippincott Williams & Wilkins on the Internet: http://www.lww.com. Lippincott Williams & Wilkins customer service representatives are available from 8:30 a.m. to 6:00 p.m., EST. Shargel_8e_FM.indd iv 07/09/12 6:05 PM  Preface This eighth edition of Comprehensive Pharmacy Review re- to the study of pharmacy—chemistry, pharmaceutics, flects the continuing evolution of pharmacy practice and pharmacology, pharmacy practice, drug therapy—is or- educational requirements. The main objective of the book is ganized to parallel the pharmacy curriculum and pre- to provide a comprehensive study guide for pharmacy stu- sented in outline form for easy use. The Comprehensive dents and other candidates who are preparing for the North Pharmacy Review may be used as a quick review (or pre- American Pharmacist Licensure Examination (NAPLEX). view) of essential topics by a diverse group of readers, This volume represents the contributions of more than 50 including specialists who provide wide expertise in pharmaceutical Matriculating pharmacy students. The organization science, pharmacy practice, and clinical pharmacy. Their and topical coverage of Comprehensive Pharmacy Review contributions to Comprehensive Pharmacy Review assure are such that many pharmacy students will want to pur- that this review guide is accurate and current as well as chase it in their first professional year and use it through- written in a comprehensible manner for students, teachers, out their pharmacy education to prepare for course and practitioners alike. This review publication, along with examinations. the separate booklet of simulated NAPLEX exams (Com- Instructors and preceptors. Comprehensive Pharmacy prehensive Pharmacy Review Practice Exams, 8th edition), Review also functions as an instructor’s manual and a provides both guidance and test practice for NAPLEX reference for teachers and tutors in pharmacy schools. candidates. Chapter outlines can be used to organize courses and to The current pharmaceutical education provides plan specific lectures. greater career opportunities for pharmacists than ever be- Professional pharmacists. Comprehensive Pharmacy Re- fore. Pharmaceutical education, including pharmaceutical view offers practitioners a convenient handbook of phar- science and practice, must prepare pharmacy practitioners macy facts. It can be used as a course refresher and as a for the future. Among the many career choices for phar- source of recent information on pharmacy practice. The macists include work in academic pharmacy, community appendices include prescription dispensing informa- pharmacy, long-term care, and consulting pharmacy, in- tion, common prescription drugs, and general pharmacy cluding hospice and home care, pharmaceutical and health references. care distributors, pharmaceutical industry, professional Foreign pharmacy graduates. Comprehensive Phar- trade organizations, uniformed (public health) services, macy Review provides a source of current informa- federal and state governments, hospital and institutional tion on pharmaceutical science, pharmacy practice, practice settings, managed care pharmacy, and other set- and clinical pharmacy for foreign pharmacy gradu- tings. Moreover, pharmacists are actively involved in health ates who may be candidates for the Foreign Pharmacy care. Examples include counseling and medication therapy, Graduate Equivalency Examination (FPGEE). The ap- disease state management, and screening programs such as pendices include prescription dispensing information, diabetes, hypertension, and high cholesterol along with the common prescription drugs, and general pharmacy more traditional role of dispensing medication and educat- references. ing patients. Many students enroll in pharmaceutical edu- cation programs that are combined with a business (MBA), research (PhD), or law (JD) degree to provide opportuni- ties in various pharmacy-related professions and other WHAT’S NEW IN THIS EDITION challenging fields. The continuing evolution of pharmacy practice is reflected Comprehensive Pharmacy Review is principally writ- by the licensure examinations developed by the National ten for NAPLEX candidates. However, the book is also Association of Boards of Pharmacy (NABP) to assess the intended for a broader audience of pharmacy undergrad- competence of pharmacy candidates. For this reason, we uates and health professionals who seek detailed summa- have requested and have been given permission by NABP ries of pharmacy subjects. A wide range of topics central to reproduce the competency statements for the NABP v Shargel_8e_FM.indd v 07/09/12 6:05 PM  vi Preface examination (NAPLEX) in the front matter of this edition ORGANIZATIONAL PHILOSOPHY of Comprehensive Pharmacy Review. AND CHAPTER STRUCTURE Because of the significant advances in drug therapy since the publication of the last edition, this edition has The organization of the eight edition reflects the current un- been revised to reflect the current educational and com- dergraduate pharmacy curriculum. Pharmaceutical Sciences petency requirements for a successful career in pharmacy. (Chapters 1–18), contains subject matter pertaining to the Many of the chapters have been revised to represent the basic science of pharmacy. Pharmacy Practice (Chapters latest understanding of disease and therapeutic manage- 19–64), contains subject matter for the practice of pharmacy ment. New chapters, such as Pain Management Including with emphasis on pharmaceutical care. Each chapter of the Migraines, Hepatic Disorders, Pediatrics, Geriatrics, book contains topic outlines and practice questions accord- Women’s Health have been added to reflect the needs of ing to the pharmacy school curriculum. special populations. The addition of the chapter, Biosta- At the front matter of this book, you’ll find guidelines tistics and Medical Literature Evaluation provides a basis for taking a test and an introduction to the NAPLEX exam, for the evaluation of new therapeutic moieties that will be including the actual NAPLEX blueprint. The appendices of marketed in the future. this book are compilations of handy reference tables. Shargel_8e_FM.indd vi 07/09/12 6:06 PM  Contributors S. Thomas Abraham, PhD Lawrence H. Block, PhD, RPh Associate Professor of Pharmacology and Toxicology Professor of Pharmaceutics Department of Pharmaceutical Sciences Division of Pharmaceutical Sciences Campbell University College of Pharmacy and Health Sciences Mylan School of Pharmacy Buies Creek, North Carolina Duquesne University Pittsburgh, Pennsylvania Michael L. Adams, PharmD, PhD Assistant Professor of Medicinal Chemistry James A. Boyd, PharmD, MBA Department of Pharmaceutical Sciences Associate Professor and Director Campbell University College of Pharmacy and Health Sciences Joint PharmD/MBA Program Buies Creek, North Carolina Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina Loyd V. Allen Jr., PhD Professor Emeritus K. Paige D. Brown, PharmD College of Pharmacy Assistant Director of Experiential Education University of Oklahoma Assistant Professor of Pharmacy Practice Oklahoma City, Oklahoma Campbell University College of Pharmacy and Health Sciences Editor-In-Chief Buies Creek, North Carolina International Journal of Pharmaceutical Compounding Edmond, Oklahoma Todd A. Brown, MHP, RPh Clinical Instructor and Vice Chair Teresa M. Bailey, PharmD, BCPS, FCCP Department of Pharmacy Practice Department of Pharmacy Practice Bouve College of Health Sciences School of Pharmacy Ferris State University College of Pharmacy Northeastern University ProMed Family Practice Boston, Massachusetts Portage, Michigan Marcia L. Buck, PharmD, FCCP, FPPAG Connie Lee Barnes, PharmD Clinical Pharmacy Coordinator, Children’s Hospital Professor Associate Professor, Pediatrics Director, Drug Information Center School of Medicine Department of Pharmacy Practice Clinical Associate Professor Campbell University College of Pharmacy and Health Sciences School of Nursing Buies Creek, North Carolina University of Virginia Health System, Department of Pharmacy Services Caryn Domenici Belisle, RPh Charlottesville, Virginia Pharmacy Manager, Sterile Products and Robotics Service Department of Pharmacy Services Robert Cisneros, PhD Brigham and Women’s Hospital Associate Professor Boston, Massachusetts Department of Pharmacy Practice Campbell University College of Pharmacy and Health Sciences Brooke Bernhardt, PharmD, BCOP Buies Creek, North Carolina Clinical Pharmacy Specialist, Hematology/Oncology Texas Children’s Hospital Valerie B. Clinard, PharmD Houston, Texas Associate Director, Drug Information Assistant Professor, Pharmacy Practice Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina vii Shargel_8e_FM.indd vii 07/09/12 6:06 PM  viii Contributors Dean S. Collier, PharmD, BCPS Charles Herring, PharmD, BCPS, CPP Assistant Professor Associate Professor, Campbell University Department of Pharmacy Practice College of Pharmacy and Health Sciences University of Nebraska Medical Center Clinical Pharmacist, Adult Medicine Team Clinical Pharmacist Downtown Health Plaza of Baptist Hospitals Department of Pharmacy Practice Winston-Salem, North Carolina The Nebraska Medical Center Omaha, Nebraska Manish Issar, PhD Assistant Professor of Pharmacology Stephen C. Dragotakes, RPh, BCNP College of Osteopathic Medicine PET Nuclear Pharmacy Western University of Health Sciences PET Pharmaceutical Production Manager Pomona, California Division of Nuclear Medicine and Molecular Imaging Department of Radiology Alan F. Kaul, PharmD, MS, MBA, FCCP Massachusetts General Hospital President Boston, Massachusetts Medical Outcomes Management, Inc. Sharon, Massachusetts Elise Dunzo, PhD Adjunct Professor of Pharmacy Director, Clinical Pharmacology and Pharmacokinetics Department of Pharmacy Practice Applied Biopharmaceutics, LLC University of Rhode Island College of Pharmacy Raleigh, North Carolina Kingston, Rhode Island Adjunct Professor of Pharmacy Practice Alice C. Engelbrecht, PharmD Department of Pharmacy Practice Clinical Coordinator for Pharmacy Clinical Services School of Pharmacy Oklahoma University Medical Center Massachusetts College of Pharmacy and Health Sciences Oklahoma City, Oklahoma Boston, Massachusetts John Fanikos, RPh, MBA Kevin P. Keating, MD Director of Pharmacy Business Director, Cardiothoracic Surgical ICU Department of Pharmacy Services Department of Surgery Brigham and Women’s Hospital Hartford Hospital Boston, Massachusetts Hartford, Connecticut Assistant Professor of Surgery Robert B. Greenwood, RPh, PhD Department of Surgery Associate Dean of Academic Affairs University of Connecticut School of Medicine Professor of Pharmaceutical Sciences Farmington, Connecticut Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina Julie J. Kelsey, PharmD Clinical Pharmacy Specialist James B. Groce III, PharmD, CACP Women’s Health and Family Medicine Professor, Department of Pharmacy Practice Department of Pharmacy Services Campbell University College of Pharmacy and Health Sciences University of Virginia Health System Clinical Assistant Professor of Medicine, Department of Medicine Charlottesville, Virginia University of North Carolina School of Medicine Clinical Pharmacy Specialist—Anticoagulation D. Byron May, PharmD, BCPS Department of Pharmacy Professor Cone Health Department of Pharmacy Practice Greensboro, North Carolina Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina Rebekah R. Arthur Grube, PharmD, BCPS Clinical Specialist in Adult Internal Medicine Pharmacist Consultant Department of Pharmacy Charlotte, North Carolina Duke University Hospital Durham, North Carolina Terri S. Hamrick, PhD Associate Professor David I. Min, PharmD, MS, FCCP Department of Pharmaceutical Sciences Professor College of Pharmacy and Health Sciences Department of Pharmacy Practice and Administration Campbell University Western University of Health Sciences, College of Pharmacy Buies Creek, North Carolina Pomona, California Shargel_8e_FM.indd viii 07/09/12 6:06 PM  Contributors ix Alan H. Mutnick, PharmD, FASHP, RPh Gurvinder Singh Rekhi, PhD Corporate Director/Clinical Services Director, Research and Development Catholic Health Partners Elan Drug Delivery, Inc. Cincinnati, Ohio Gainesville, Georgia Andrew J. Muzyk, PharmD Gerald E. Schumacher, PharmD, MS, PhD Assistant Professor Professor of Pharmacy, Emeritus Department of Pharmacy Practice Bouve College of Health Sciences School of Pharmacy Campbell University College of Pharmacy and Health Sciences Northeastern University Buies Creek, North Carolina Boston, Massachusetts Clinical Pharmacy Specialist Department of Pharmacy Leon Shargel, PhD, RPh Duke University Hospital Manager Durham, North Carolina Applied Biopharmaceutics, LLC Raleigh, North Carolina Eric C. Nemec, PharmD, BCPS Affiliate Associate Professor Clinical Assistant Professor Department of Pharmaceutics Department of Pharmacy Practice School of Pharmacy Western New England University Virginia Commonwealth University Springfield, Massachusetts Richmond, Virginia Informatics Specialist Adjunct Associate Professor Department of Pharmacy School of Pharmacy Holyoke Medical Center University of Maryland Holyoke, Massachusetts Baltimore, Maryland Jeffrey P. Norenberg, PharmD, BCNP, FASHP, FAPhA Penny S. Shelton, PharmD, CGP, FASCP Professor, Chair, Radiopharmaceutical Sciences Program Vice-Chair, Experiential and Continuing Education College of Pharmacy, University of New Mexico Associate Professor, Department of Pharmacy Practice Albuquerque, New Mexico Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina Roy A. Pleasants II, PharmD Associate Professor Jennifer D. Smith, PharmD, CPP, BC-ADM, CDE, C-TTS Department of Pharmacy Practice Associate Professor Campbell University College of Pharmacy and Health Sciences Department of Pharmacy Practice Buies Creek, North Carolina Campbell University College of Pharmacy and Health Sciences Clinical Assistant Professor Buies Creek, North Carolina Division of Pulmonary Medicine Clinical Pharmacist Practitioner Duke University School of Medicine Wilson Community Health Center Durham, North Carolina Wilson, North Carolina John J. Ponzillo, PharmD Paul F. Souney, MS, RPh Critical Care Pharmacist Vice President St. John’s Mercy Medical Center Medical Affairs and Pharmacotherapy Management Saint Louis, Missouri Medical Outcomes Management, Inc. Sharon, Massachusetts Robert A. Quercia, MS, RPh Editor and Co-Coordinator of Focus Column Formulary Journal Linda M. Spooner, PharmD, BCPS with Added Medical Editor, University of Connecticut/Hartford Hospital Qualifications in Infectious Diseases Evidenced-based Practice Center Associate Professor of Pharmacy Practice Hartford, Connecticut Department of Pharmacy Practice Adjunct Associate Clinical Professor Massachusetts College of Pharmacy and Health Sciences University of Connecticut School of Pharmacy School of Pharmacy-Worcester/Manchester Storrs, Connecticut Worcester, Massachusetts Clinical Pharmacy Specialist in Infectious Diseases Azita Razzaghi, RPh, PharmD Department of Pharmacy Associate Director Saint Vincent Hospital Pharmacovigilance Worcester, Massachusetts Genzyme Corporation Cambridge, Massachusetts Shargel_8e_FM.indd ix 07/09/12 6:06 PM  x Contributors Gilbert A. Steiner, PharmD Jenny A. Van Amburgh, PharmD, FAPhA, BCACP, CDE Associate Professor Associate Clinical Professor and Assistant Dean for Academic Department of Pharmacy Practice Affairs Campbell University College of Pharmacy and Health Sciences Department of Pharmacy Practice Buies Creek, North Carolina Bouve College of Health Sciences School of Pharmacy Northeastern University Larry N. Swanson, PharmD, FASHP, RPh Boston, Massachusetts Professor and Chairman Director of Clinical Pharmacy Services & Clinical Pharmacist Department of Pharmacy Practice Clinical Pharmacy Services Campbell University College of Pharmacy and Health Sciences Harbor Health Services, Inc. Buies Creek, North Carolina Dorchester, Massachusetts Ryan S. Swanson, PharmD, RPh Christopher Vitale, PharmD Clinical Pharmacist Clinical Pharmacist Kerr Drug Clinical Informatics Research and Development Fuquay-Varina, North Carolina Partners Healthcare System Wellesley, Massachusetts Heather A. Sweeney, PharmD, RPh Clinical Manager Susanna Wu-Pong, PhD Pharmaceutical Distribution Associate Professor Cardinal Health Director, Pharmaceutical Sciences Graduate Program Cincinnati, Ohio Dean’s Office Virginia Commonwealth University Barbara Szymusiak-Mutnick, BS Pharm, MHP, RPh Richmond, Virginia Home Infusion Pharmacist Walgreen Home Infusion Pharmacy Anthony E. Zimmermann, BS, PharmD Centerville, Ohio Professor and Chair Department of Pharmacy Practice Tina Harrison Thornhill, PharmD, FASCP, CGP College of Pharmacy Associate Professor Western New England University Department of Pharmacy Practice Springfield, Massachusetts Campbell University College of Pharmacy and Health Sciences Buies Creek, North Carolina Clinical Specialist, Geriatrics and Acute Rehabilitation Wake Forest Baptist Health The Sticht Center on Aging and Rehabilitation Winston-Salem, North Carolina Shargel_8e_FM.indd x 07/09/12 6:06 PM  Contents Preface v 12 Pharmacology and Medicinal Chemistry of Contributors vii Endocrine and Related Drugs 245 Contents xi Michael L. Adams, S. Thomas Abraham Taking a Test xiv Introduction to the NAPLEX xvii 13 Drug–Drug and Drug–Nutrient Interactions 271 NAPLEX blueprint xix Alice C. Engelbrecht, Leon Shargel 1 Pharmaceutical Calculations 1 14 Drug Information Resources 290 Robert B. Greenwood Paul F. Souney, Connie Lee Barnes, Valerie B. Clinard 2 Pharmaceutical Principles and Drug Dosage Forms 18 15 Biostatistics 303 Charles Herring Lawrence H. Block 3 Biopharmaceutics and Drug Delivery Systems 69 16 Clinical Toxicology 317 Lawrence H. Block John J. Ponzillo 4 Extemporaneous Prescription Compounding 81 17 Sterile Products 334 Loyd V. Allen Jr. Christopher Vitale, Caryn Domenici Belisle, John Fanikos 5 Basic Pharmacokinetics 102 18 Parapharmaceuticals, Diagnostic Aids, and Elise Dunzo, Leon Shargel Medical Devices 362 Jenny A. Van Amburgh, Todd A. Brown 6 Bioavailability and Bioequivalence 122 Manish Issar, Leon Shargel 19 Over-the-Counter Otic, Dental, and Ophthalmic 7 Biotechnology Drug Products 133 Agents 373 Susanna Wu-Pong Jennifer D. Smith, Connie Lee Barnes 8 Drug Metabolism, Prodrugs, and 20 Over-the-Counter Dermatological Agents 392 Pharmacogenetics 143 Larry N. Swanson, Ryan S. Swanson Michael L. Adams, S. Thomas Abraham 21 Over-the-Counter Weight Control, Sleep, and 9 Pharmacology and Medicinal Chemistry of Drugs Smoking-Cessation Aids 423 Affecting the Nervous System 165 Jennifer D. Smith S. Thomas Abraham, Michael L. Adams 22 Over-the-Counter Agents for Fever, Pain, Cough, 10 Pharmacology and Medicinal Chemistry of Cold, and Allergic Rhinitis 436 Cardiovascular and Diuretic Drugs 198 Jennifer D. Smith, Gerald E. Schumacher S. Thomas Abraham, Michael L. Adams 11 Pharmacology and Medicinal Chemistry of 23 Over-the-Counter Agents for Constipation, Autacoids, Nonsteroidal Anti-inflammatory Diarrhea, Hemorrhoids, and Heartburn 455 Drugs, and Antihistamines 226 Jennifer D. Smith Michael L. Adams, S. Thomas Abraham Shargel_8e_FM.indd xi 07/09/12 6:06 PM  xii Contents 24 Over-the-Counter Menstrual, Vaginal, and 40 Mood Disorders, Anxiety Spectrum Disorders, Contraceptive Agents 469 Attention-Deficit Hyperactivity Disorder (ADHD), Jennifer D. Smith and Insomnia 803 Rebekah R. Arthur Grube, Andrew J. Muzyk 25 Herbal Medicines and Nutritional Supplements 480 41 Asthma and Chronic Obstructive Pulmonary Teresa M. Bailey Disease 829 Roy A. Pleasants II 26 Clinical Pharmacokinetics and Therapeutic Drug Monitoring 499 42 Osteoarthritis and Rheumatoid Arthritis 863 Gerald E. Schumacher Tina Harrison Thornhill 27 Pediatrics 510 43 Hyperuricemia and Gout 874 Marcia L. Buck Larry N. Swanson 28 Geriatrics 519 44 Peptic Ulcer Disease and Related Acid-Associated Alan H. Mutnick Disorders 886 Paul F. Souney, Anthony E. Zimmermann 29 Women’s Health 528 Julie J. Kelsey 45 Diseases of the Bowel: Inflammatory Bowel Disease and Irritable Bowel Syndrome 907 30 Clinical Laboratory Tests 542 Dean S. Collier D. Byron May 46 Diabetes Mellitus 930 31 Coronary Artery Disease 560 Jennifer D. Smith Alan H. Mutnick 47 Thyroid Disease 954 32 Cardiac Arrhythmias 590 Eric C. Nemec Alan H. Mutnick 48 Renal Disorders 978 33 Hypertension 612 Heather A. Sweeney Alan H. Mutnick 49 Hepatic Disorders 992 34 Heart Failure 638 Heather A. Sweeney Alan H. Mutnick 50 Cancer Chemotherapy 1001 35 Thromboembolic Diseases 659 Brooke Bernhardt James B. Groce III 51 Pain Management 1019 36 Infectious Diseases 674 Alan F. Kaul Paul F. Souney, Anthony E. Zimmermann, Linda M. Spooner 52 Nutrition and the Hospitalized Patient 1036 Robert A. Quercia, Kevin P. Keating 37 Seizure Disorders 743 Azita Razzaghi 53 Immunosuppressive Agents in Organ Transplantation 1056 38 Parkinson Disease 773 David I. Min Azita Razzaghi 54 Outcomes Research and 39 Schizophrenia 793 Pharmacoeconomics 1065 Rebekah R. Arthur Grube, Andrew J. Muzyk Alan H. Mutnick Index I-1 Shargel_8e_FM.indd xii 07/09/12 6:06 PM  Contents xiii Additional Chapters Published Online at 62 Medication Errors 1196 thePoint.lww.com Robert Cisneros 63 Federal Pharmacy Law 1202 55 Drug Product Development in the Pharmaceutical James A. Boyd Industry 1074 Gurvinder Singh Rekhi, Leon Shargel 64 Reviewing and Dispensing Prescription and Medication Orders 1233 56 Microbiology 1082 Todd A. Brown Terri S. Hamrick Appendix A Common Prescription Drugs and 57 Immunology 1103 Over-the-Counter Products 1241 Terri S. Hamrick, Gilbert A. Steiner Appendix B Prescription Dispensing Information 58 Principles of Pharmacology and Medicinal and Metrology 1250 Chemistry 1135 S. Thomas Abraham, Michael L. Adams Appendix C Reference Charts for Patient Counseling 1255 59 Nuclear Pharmacy 1160 Stephen C. Dragotakes, Jeffrey P. Norenberg Appendix D National and State Boards of Pharmacy Contact 60 Medication Therapy Management 1180 Information 1315 Penny S. Shelton, K. Paige D. Brown Appendix E Budgeting for Drug Information 61 Adverse Drug Reaction Reporting 1190 Resources 1321 Barbara Szymusiak-Mutnick Shargel_8e_FM.indd xiii 07/09/12 6:06 PM  Taking a Test One of the least attractive aspects of pursuing an education examination. Relying too heavily on memorized material is the necessity of being examined on the material that has causes anxiety, and the more anxious students become dur- been presented. Instructors do not like to prepare tests, and ing a test, the less learned knowledge they are likely to use. students do not like to take them. However, students are required to take many examina- tions during their learning careers, and little, if any, time is ATTITUDE AND APPROACH spent acquainting them with the positive aspects of tests and A positive attitude and a realistic approach are essential with systematic and successful methods for approaching to successful test taking. If the student concentrates on them. Students perceive tests as punitive and sometimes feel the negative aspects of tests or on the potential for failure, as if they were merely opportunities for the instructor to dis- anxiety increases and performance decreases. A negative at- cover what the student has forgotten or has never learned. titude generally develops if the student concentrates on “I Students need to view tests as opportunities to display their must pass” rather than on “I can pass.” “What if I fail?” be- knowledge and to use them as tools for developing prescrip- comes the major factor motivating the student to run from tions for further study and learning. failure rather than toward success. This results from placing While preparing for any exam, class and board exams too much emphasis on scores. The score received is only one as well as practice exams, it is important that students learn aspect of test performance. Test performance also indicates as much as they can about the subject they will be tested and the student’s ability to use differential reasoning. are prepared to discover just how much they may not know. In each question with five alternatives, of which one is cor- Students should study to acquire knowledge, not just to pre- rect, there are four alternatives that are incorrect. If deductive pare for tests. For the well-prepared student, the chances of reasoning is used, the choices can be viewed as having possibil- passing far exceed the chances of failing. ities of being correct. The elimination of wrong choices increas- es the odds that a student will be able to recognize the correct choice. Even if the correct choice does not become evident, the MATERIALS NEEDED FOR TEST probability of guessing correctly increases. Eliminating incor- PREPARATION rect choices on a test can result in choosing the correct answer. In preparing for a test, most students collect far too much Answering questions based on what is incorrect is study material, only to find that they simply do not have difficult for many students because they have had nearly time to go through all of it. They are defeated before they be- 20 years of experience taking tests with the implied asser- gin because either they cannot get through all the material, tion that knowledge can be displayed only by knowing what leaving areas unstudied, or they race through the material so is correct. It must be remembered, however, that students quickly that they cannot benefit from the activity. can display knowledge by knowing something is wrong, just It is generally more efficient for the student to use ma- as they can display it by knowing something is right. terials already at hand—that is, class notes, one good outline to cover and strengthen all areas and to quickly review the whole topic, and one good text as a reference for complex PREPARING FOR THE EXAMINATION material that requires further explanation. 1. Study for yourself. Although some of the material may Also, many students attempt to memorize far too seem irrelevant, the more you learn now, the less you will much information, rather than learning and understanding have to learn later. Also, do not let the fear of the test rob you less material and then relying on that learned information of an important part of your education. If you study to learn, to determine the answers to questions at the time of the the task is less distasteful than studying solely to pass a test. xiv Shargel_8e_FM.indd xiv 07/09/12 6:06 PM  Taking a Test xv 2. Review all areas. You should not be selective by study- Adjectives and adverbs can completely change the meaning of ing perceived weak areas and ignoring perceived strong questions—pay close attention to them. The knowledge and areas. Cover all of the material, putting added emphasis application of grammar often are key to dissecting questions. on weak areas. 3. Attempt to understand, not just to memorize, the material. Ask yourself: To whom does the material MULTIPLE CHOICE QUESTIONS apply? When does it apply? Where does it apply? How Read the question and the choices carefully to become fa- does it apply? Understanding the connections among miliar with the data provided. Remember in multiple choice these points allows for longer retention and aids in those questions, there is one correct answer and there are four situations when guessing strategies may be needed. distractors, or incorrect answers. (Distractors are plausible 4. Try to anticipate questions that might appear on the and possibly correct, otherwise they would not be called test. Ask yourself how you might construct a question distractors.) They are generally correct for part of the ques- on a specific topic. tion but not for the entire question. Dissecting the question 5. Give yourself a couple days of rest before the test. into parts helps eliminate distractors. Studying up to the last moment will increase your anxi- Many students think that they must always start at op- ety and cause potential confusion. tion A and make a decision before they move to option B, thus forcing decisions they are not ready to make. Your first decisions should be made on those choices you feel the most TAKING THE EXAMINATION confident about. 1. Be sure to pace yourself to use the test time optimally. Compare the choices with each part of the question. To You should use all of your allotted time; if you finish be wrong, a choice needs to be incorrect for only part of the too early, you probably did so by moving too quickly question. To be correct, it must be totally correct. If you be- through the test. lieve a choice is partially incorrect, tentatively eliminate that 2. Read each question and all the alternatives carefully be- choice. Make notes next to the choices regarding tentative fore you begin to make decisions. Remember, the ques- decisions. One method is to place a minus sign next to the tions contain clues, as do the answer choices. choices you are certain are incorrect and a plus sign next to 3. Read the directions for each question set carefully. You those that potentially are correct. Finally, place a zero next would be amazed at how many students make mistakes to any choice you do not understand or need to come back in tests simply because they have not paid close attention to for further inspection. Do not feel that you must make to the directions. final decisions until you have examined all choices carefully. 4. It is not advisable to leave blanks with the intention of com- When you have eliminated as many choices as you can, ing back to answer questions later. If you feel that you must decide which of those that remain has the highest probabil- come back to a question, mark the best choice and place ity of being correct. Above all, be honest with yourself. If a note in the margin. Generally speaking, it is best not to you do not know the answer, eliminate as many choices as change answers once you have made a decision. Your con- possible and choose reasonably. sidered reaction and first response are correct more often Multiple choice questions are not as difficult as some than are changes made out of frustration or anxiety. students make them. There are two general types of multiple 5. Do not let anxiety destroy your confidence. If you have choice questions, including (1) the more traditional single prepared conscientiously, you know enough to pass. Use answer type question in which the candidate must decide all that you have learned. one of five choices (a, b, c, d, or e) and (2) the combined re- 6. Do not try to determine how well you are doing as you sponse (“K” type) multiple choice question, which is shown proceed. You will not be able to make an objective as- next. In this case, these are the questions for which you must sessment, and your anxiety will increase. select from the following choices: 7. Do not become frustrated or angry about what appear A if only I is correct to be bad or difficult questions. You simply do not know B if only III is correct the answers; you cannot know everything. C if I and II are correct D if II and III are correct SPECIFIC TEST-TAKING STRATEGIES E if I, II, and III are correct Read the entire question carefully, regardless of format. Test Remember that the name for this type of question is questions have multiple parts. Concentrate on picking out the multiple true–false and then use this concept. Become famil- pertinent key words that will help you problem-solve. Words iar with each choice and make notes. Then concentrate on such as always, all, never, mostly, primarily, and so forth the one choice you feel is definitely incorrect. If you can find play significant roles. In all types of questions, distractors one incorrect alternative, you can eliminate three choices with terms such as always or never most often are incorrect. immediately and be down to a 50–50 probability of guessing Shargel_8e_FM.indd xv 07/09/12 6:06 PM  xvi Taking a Test the correct answer. If choice A is incorrect, so are choices means that it is just as beneficial to look up the incorrect C and E; if choice B is incorrect, so are choices D and E. choices as the correct choices to discover specifically why Therefore, you are down to a 50–50 probability of guessing they are incorrect. In this way, it is possible to learn better the correct answer. test-taking skills as the subtlety of question construction is After eliminating the choices you are sure are incorrect, uncovered. concentrate on the choice that will make your final decision. In addition, it is advisable to go back and attempt to re- For instance, if you discard choice I, you have eliminated structure each question to see if all the choices can be made alternatives A, C, and E. This leaves B (III) and D (II and correct by modifying the question. By doing this, you will III). Concentrate on choice II and decide if it is true or false. learn four times as much. By all means, look up the right (Take the path of least resistance and concentrate on the answer and explanation. Then, focus on each of the other smallest possible number of items while making a decision.) choices, and ask yourself under what conditions, if any, they Obviously, if none of the choices is found to be incorrect, the might be correct. answer is E (I, II, III). SUMMARY GUESSING Ideally, examinations are designed to determine how much Nothing takes the place of a firm knowledge base; but hav- material students have learned and how that material is used ing little information to work with, you may find it necessary in the successful completion of the examination. Students to guess at the correct answer. A few simple rules can help will be successful if these suggestions are followed: increase your guessing accuracy. Always guess consistently Develop a positive attitude and maintain that attitude. if you have no idea what is correct—that is, after eliminating Be realistic in determining the amount of material you all that you can, make the choice that agrees with your intu- attempt to master and in the score you hope to attain. ition or choose the option closest to the top of the list that Read the directions for each type of question and the has not been eliminated as a potential answer. questions themselves closely, and follow the directions When guessing at questions that present with choices carefully. in numeric form, you will often find the choices listed in an Bring differential reasoning to each question in the ascending or descending order. It is generally not wise to examination. guess the first or last alternative because these are usually Guess intelligently and consistently when guessing strat- extreme values and are most likely incorrect. egies must be used. Use the test as an opportunity to display your knowledge USING A PRACTICE EXAM TO LEARN and as a tool for developing prescriptions for further study and learning. All too often, students do not take full advantage of practice exams. There is a tendency to complete the exam, score it, Board examinations are not easy. They may be almost look up the correct answer to those questions missed, and impossible for those who have unrealistic expectations or then forget the entire thing. for those who allow misinformation concerning the exams In fact, great educational benefits could be derived to produce anxiety out of proportion to the task at hand. if students would spend more time using practice tests as Examinations are manageable if they are approached with a learning tools. As mentioned previously, incorrect choices positive attitude and with consistent use of all of the infor- in test questions are plausible and partially correct, other- mation the student has learned. wise they would not fulfill their purpose as distractors. This Michael J. O’Donnell Shargel_8e_FM.indd xvi 07/09/12 6:06 PM  Introduction to the NAPLEX After graduation from an accredited pharmacy program, online at http://www.nabp.net. Before submitting registra- the prospective pharmacist must demonstrate the compe- tion materials, the pharmacy candidate should contact the tency to practice pharmacy. The standards of competence board of pharmacy for additional information regarding for the practice of pharmacy are set by each state board of procedures, deadline dates, and required documentation. pharmacy. NAPLEX—The North American Pharmacist The NAPLEX is a computer-adaptive test. These ques- Licensure Examination—is the principal instrument used tions measure the prospective pharmacist’s ability to measure by the state board of pharmacy to assess the knowledge and pharmacotherapy and therapeutic outcomes, prepare and dis- proficiency necessary for a candidate to practice pharmacy. pense medications, and implement and evaluate information The National Association of Boards of Pharmacy (NABP) for optimal health care. The computer adaptive exam tests a is an independent, international, and impartial association candidate’s knowledge and ability by assessing the answers that assists member boards and jurisdictions in develop- before presenting the next test question. If the answer is cor- ing, implementing, and enforcing uniform standards for rect, the computer will select a more difficult question from the purpose of protecting the public health. NABP devel- the test item pool in an appropriate content area; if the an- ops examinations that enable boards of pharmacy to assess swer is incorrect, an easier question will be selected by the the competence of candidates seeking licensure to prac- computer. The NAPLEX score is based on the difficulty level tice pharmacy. Each state board of pharmacy may impose of the questions answered correctly. additional examinations. The two major examinations NAPLEX consists of 185 multiple choice test questions. developed by NABP are In the past, 150 questions were used to calculate the test score. The remaining 35 items served as pretest questions The North American Pharmacist Licensure Examination and do not affect the NAPLEX score. Pretest questions are (NAPLEX) administered to evaluate the item’s difficulty level for pos- Multistate Pharmacy Jurisprudence Examination (MPJE) sible inclusion as a scored question in future exams. These Foreign pharmacy graduates must pass the Foreign pretest questions are dispersed throughout the exam and Pharmacy Graduate Equivalency Examination (FPGEE) as cannot be identified by the candidate. part of the Foreign Pharmacy Graduate Equivalency Cer- A majority of the questions on the NAPLEX are asked tification process. Foreign-educated pharmacists awarded in a scenario-based format (i.e., patient profiles with accom- FPGEC certification is considered to have partially fulfilled panying test questions). To properly analyze and answer the eligibility requirements for licensure in those states that ac- questions presented, the candidate must refer to the infor- cept the certification. mation provided in the patient profile. Some questions ap- A description of these computerized examinations and pear in a stand-alone format and should be answered solely registration information may be found on the NABP website from the information provided in the question. xvii Shargel_8e_FM.indd xvii 07/09/12 6:06 PM Shargel_8e_FM.indd xviii 07/09/12 6:06 PM  NAPLEX Blueprint THE NAPLEX COMPETENCY 1.2.1 Identify specific uses and indications for drug STATEMENTS products and recommend drugs of choice for specific diseases or medical conditions. All NAPLEX questions are based on competency statements 1.2.2 Identify the chemical/pharmacologic classes of that are reviewed and revised periodically. The NAPLEX therapeutic agents and describe their known or postu- Competency Statements describe the knowledge, judg- lated sites and mechanisms of action. ment, and skills that the candidate is expected to demon- 1.2.3 Evaluate drug therapy for the presence of pharma- strate as an entry-level pharmacist. A complete description cotherapeutic duplications and interactions with other of the NAPLEX Competency Statements is published on the drugs, food, and diagnostic tests. NABP website and is reproduced, with permission of NABP. 1.2.4 Identify and evaluate potential contraindications A strong understanding of the Competency Statements will and provide information about warnings and precau- aid in your preparation to take the examination. tions associated with a drug product’s active and inactive ingredients. Area 1 Assess Pharmacotherapy to 1.2.5 Identify physicochemical properties of drug sub- stances that affect their solubility, pharmacodynamic and Assure Safe and Effective Therapeutic pharmacokinetic properties, pharmacologic actions, and Outcomes (Approximately 56% of Test) stability. 1.1.0 Identify, interpret, and evaluate patient informa- 1.2.6 Evaluate and interpret pharmacodynamic and tion to determine the presence of a disease or medical pharmacokinetic principles to calculate and determine condition, assess the need for treatment and/or referral, appropriate drug dosing regimens. and identify patient-specific factors that affect health, 1.2.7 Identify appropriate routes of administration, dosage pharmacotherapy, and/or disease management. forms, and pharmaceutical characteristics of drug dosage 1.1.1 Identify and assess patient information including forms and delivery systems to assure bioavailability and medication, laboratory, and disease state histories. enhance therapeutic efficacy. 1.1.2 Identify patient-specific assessment and diagnos- 1.3.0 Evaluate and manage drug regimens by monitor- tic methods, instruments, and techniques and interpret ing and assessing the patient and/or patient information, their results. collaborating with other health care professionals, and 1.1.3 Identify and define the etiology, terminology, signs, providing patient education to enhance safe, effective, and symptoms associated with diseases and medical con- and economic patient outcomes. ditions and their causes and determine if medical referral 1.3.1 Identify pharmacotherapeutic outcomes and end is necessary. points. 1.1.4 Identify and evaluate patient genetic, biosocial fac- 1.3.2 Evaluate patient signs and symptoms and the find- tors, and concurrent drug therapy relevant to the main- ings of monitoring tests and procedures to determine the tenance of wellness and the prevention or treatment of a safety and effectiveness of pharmacotherapy. Recommend disease or medical condition. needed follow-up evaluations or tests when appropriate. 1.2.0 Evaluate information about pharmacoeconomic 1.3.3 Identify, describe, and provide information regard- factors, dosing regimen, dosage forms, delivery systems ing the mechanism of adverse reactions, allergies, side and routes of administration to identify and select opti- effects, iatrogenic, and drug-induced illness, including mal pharmacotherapeutic agents for patients. their management and prevention. xix Shargel_8e_FM.indd xix 07/09/12 6:06 PM  xx NAPLEX Blueprint 1.3.4 Identify, prevent, and address methods to remedy 2.3.3 Identify the mechanism of and evidence for the in- medication nonadherence, misuse, or abuse. compatibility or degradation of a product or preparation 1.3.5 Evaluate current drug regimens and recommend and methods for achieving its stability. pharmacotherapeutic alternatives or modifications. Area 3 Assess, Recommend, and Provide Area 2 Assess Safe and Accurate Health Care Information that Promotes Preparation and Dispensing of Public Health (Approximately 11% of Test) Medications (Approximately 33% of Test) 3.1.0 Identify, evaluate, and apply information to pro- mote optimal health care. 2.1.0 Demonstrate the ability to perform calcula- 3.1.1 Identify the typical content of specific sources of tions required to compound, dispense, and administer drug and health information for both health care pro- medication. viders and consumers, and recommend appropriate re- 2.1.1 Calculate the quantity of medication to be com- sources to address questions or needs. pounded or dispensed; reduce and enlarge formulation 3.1.2 Evaluate the suitability, accuracy, and reliability of quantities and calculate the quantity or ingredients needed clinical and pharmacoeconomic data by analyzing exper- to compound the proper amount of the preparation. imental design, statistical tests, interpreting results, and 2.1.2 Calculate nutritional needs and the caloric content formulating conclusions. of nutrient sources. 3.2.0 Recommend and provide information to educate 2.1.3 Calculate the rate of drug administration. the public and health care professionals regarding medi- 2.1.4 Calculate or convert drug concentrations, ratio cal conditions, wellness, dietary supplements, and medi- strengths, and/or extent of ionization. cal devices. 2.2.0 Demonstrate the ability to select and dispense 3.2.1 Recommend and provide health care information medications in a manner that promotes safe and effec- regarding the prevention and treatment of diseases and tive use. medical conditions, including emergency patient care 2.2.1 Identify drug products by their generic, brand, and/ and vaccinations. or common names. 3.2.2 Recommend and provide health care information 2.2.2 Identify whether a particular drug dosage strength regarding nutrition, lifestyle, and other nondrug mea- or dosage form is commercially available and whether it sures that promote health or prevent the progression of a is available on a nonprescription basis. disease or medical condition. 2.2.3 Identify commercially available drug products by 3.2.3 Recommend and provide information regarding their characteristic physical attributes. the documented uses, adverse effects, and toxicities of 2.2.4 Assess pharmacokinetic parameters and quality dietary supplements. assurance data to determine equivalence among manu- 3.2.4 Recommend and provide information regarding factured drug products, and identify products for which the selection, use, and care of medical/surgical applianc- documented evidence of inequivalence exists. es and devices, self-care products, and durable medical 2.2.5 Identify and provide information regarding appro- equipment, as well as products and techniques for self- priate packaging, storage, handling, administration, and monitoring of health status and medical conditions. disposal of medications. 2.2.6 Identify and provide information regarding the ap- NABP offers candidates who are preparing for the propriate use of equipment and apparatus required to NAPLEX—the Pre-NAPLEX, which is similar to the ac- administer medications. tual NAPLEX and allows candidates to gain experience 2.3.0 Demonstrate the knowledge to prepare and com- in answering questions before examination day. The Pre- pound extemporaneous preparations and sterile products. NAPLEX can be accessed via the Internet at the following 2.3.1 Identify techniques, procedures, and equipment website: http://www.nabp.net/prenaplex/. For foreign phar- related to drug preparation, compounding, and quality macy graduates, the FPGEE Study Guide is available from assurance. NABP and includes information about the blueprint of the 2.3.2 Identify the important physicochemical properties FPGEE, sample questions, and a list of textbooks commonly of a preparation’s active and inactive ingredients. used in United States pharmacy schools. Shargel_8e_FM.indd xx 07/09/12 6:06 PM  Pharmaceutical Calculations 1 ROBERT B. GREENWOOD I. FUNDAMENTALS OF MEASUREMENT AND CALCULATION. The pharmacist is often required to perform or evaluate a variety of calculations. Many of these calculations involve the use of direct or inverse proportions. Dimensional (or unit) analysis and approximation can be useful in solving these problems. In dimensional analysis, dimensions (or units) are included with each number used in the calculation. Units common to the numerator and denominator may be canceled and the remaining units provide the units for the final answer. In approximation, each number used in the calculation is rounded to a single significant digit. Factors common to the numerator and denominator may be canceled, and the answer to this approximation should be reasonably close to the final exact answer. A. Ratio and proportion 1. Ratio. The relative magnitude of two like quantities is a ratio, which is expressed as a fraction. Certain basic principles apply to the ratio, as they do to all fractions. a. When the two terms of a ratio are multiplied or divided by the same number, the value of the ratio is unchanged. _ 2_ 1_ 2_ 1 3 2 6 3 b. Two ratios with the same value are equivalent. Equivalent ratios have equal cross products and equal reciprocals. For example: 1_ _ 2 3 6 and 16326 If two ratios are equal, then their reciprocals are equal: 1_ if _ 3_ 2 , then _ 6 3 6 1 2 2. Proportion. The expression of the equality of two ratios is a proportion. The product of the extremes is equal to the product of the means for any proportion. The way to express this, from the example cited, would be 1:3  2:6, where the means are 3 and 2, and the extremes are 1 and 6. Furthermore, the numerator of the one fraction equals the product of its denominator and the other fraction (i.e., one missing term can always be found given the other three terms). Most pharmaceutical calculations can be performed by use of proportion. a. Proper ratios. Some pharmacists use proper ratios (in which similar units are used in the numer- ator and denominator of each ratio) in their proportion calculations. Several examples follow: (1) If 240 mL of a cough syrup contains 480 mg of dextromethorphan hydrobromide, then what mass of drug is contained in a child’s dose, 1 teaspoon (5 mL) of syrup? 240 mL _ 480 mg _  5 mL x mg x_ 480  5  10 mg 240 1 Shargel_8e_CH01.indd 1 07/08/12 1:24 AM  2 Chapter 1 I. A (2) If a child’s dose (5 mL) of a cough syrup contains 10 mg of dextromethorphan hydrobro- mide, what mass of drug is contained in 240 mL? 240 mL _x mg _  5 mL 10 mg 240  10  480 mg x_ 5 (3) If the amount of dextromethorphan hydrobromide in 240 mL of cough syrup is 480 mg, what would be the volume required for a child’s dose of 10 mg? x mL 10 mg _ _ 240 mL 480 mg 10  240  5mL x_ 480 (4) How many milligrams of dextromethorphan base (molecular weight  271.4) are equiva- lent to 10 mg of dextromethorphan hydrobromide (molecular weight  352.3)? x mg 271.4 _ _ 10 mg 352.3 271.4  7.7 mg x  10  _ 352.3 b. Mixed ratios. Some pharmacists use mixed ratios (in which dissimilar units are used in the numer- ator and denominator of each ratio) in their proportion calculations. Such computations generally give correct answers, providing the conditions in which mixed ratios cannot be used are known. A later example shows mixed ratios leading to failure in the case of dilution, when inverse proportions are required. For inverse proportions, similar units must be used in the numerator and denomina- tor of each ratio. Following is an example of a mixed ratio calculation using the previous problem. 480 mg _240 mg _  10 mL x mL x  240  _10  5 mL 480 The same answer is obtained in this example whether we use proper ratios, with similar units in numerator and denominator, or mixed ratios. This is not the case when dealing with inverse proportions. 3. Inverse proportion. The most common example of the need for inverse proportion for the pharmacist is the case of dilution. Whereas in the previous examples of proportion the relationships involved direct proportion, the case of dilution calls for an inverse proportion (i.e., as volume increases, concentration decreases). The necessity of using inverse proportions for dilution problems is shown in this example. If 120 mL of a 10% stock solution is diluted to 240 mL, what is the final concentration? Using inverse proportion, x% 120 mL  _ _ 240 mL 10% 120  _10  5% 240 As expected, the final concentration is one-half of the original concentration because the volume is doubled. However, if the pharmacist attempts to use direct proportion and neglects to estimate an appropriate answer, the resulting calculation would provide an answer of 20%, which is twice the actual concentration. 10% 120 mL  _ _ 240 mL x% 240  _10  20% (incorrect answer) 120 Shargel_8e_CH01.indd 2 07/08/12 1:24 AM  Pharmaceutical Calculations 3 Likewise, the pharmacist using mixed ratios fails in this case 120 mL  _ _ 240 mL 10% x% and 240  20% (again, incorrect answer) 10  _ 120 B. Aliquot. A pharmacist requires the aliquot method of measurement when the sensitivity (the smallest quantity that can be measured with the required accuracy and precision) of the measuring device is not great enough for