Mosby’s Pharmacy Review for the NAPLEX® ISBN: 978-0-323-04910-8 Copyright # 2011 by Mosby, Inc., an affiliate of Elsevier Inc.
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Library of Congress Cataloging-in-Publication Data Mosby’s pharmacy review for the NAPLEX. -- 1st ed.
p. ; cm.
Other title: Pharmacy review for the NAPLEX
ISBN 978-0-323-04910-8 (pbk. : alk. paper) 1. Pharmacy--Outlines, syllabi, etc. 2. Pharmacy--Examinations, questions, etc. I. Title: Pharmacy review for the NAPLEX.
[DNLM: 1. Pharmaceutical Preparations–Examination Questions. 2. Pharmacy--Examination Questions. QV 18.2 M8935 2010]
RS98.M72 2010 6150.1076–dc22
2010003173
Vice President and Publisher: Linda Duncan Senior Editor: Kellie White
Senior Developmental Editor: Jennifer Watrous Publishing Services Manager: Pat Joiner-Myers Project Manager: Melissa Lastarria
Design Direction: Jessica Williams
Printed in the United States of America.
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Contributors
...LEAD CONSULTANT
MaryAnne Hochadel, PharmD, BCPS Editor Emeritus,
ELSEVIER/Gold Standard Clinical Assistant Professor University of Florida College of Pharmacy Tampa, Florida
CONTRIBUTORS
Catherine Ulbricht, PharmD Massachusetts General HospitalNatural Standard Research Collaboration Somerville, Massachusetts
Erica Rusie, PharmD
Natural Standard Research Collaboration Somerville, Massachusetts
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Reviewers
...Laurel E. Ashworth, PharmD Professor of Pharmacy Practice
Mercer University College of Pharmacy and Health Sciences
Atlanta, Georgia
Paul Juang, PharmD, BCPS Assistant Professor
Department of Pharmacy Practice St. Louis College of Pharmacy St. Louis, Missouri
Julie P. Karpinski, PharmD, BCPS Director, Drug Information
Assistant Professor, Pharmacy Practice Concordia, University School of Pharmacy Mequon, Wisconsin
Trisha LaPointe, PharmD, BCPS
Assistant Professor of Pharmacy Practice Massachusetts College of Pharmacy and Health
Sciences
Department of Pharmacy Practice School of Pharmacy-Boston Boston, Massachusetts
Donna Larson, EdD, MT(ASCP)DLM Dean of Allied Health
Mt. Hood Community College Gresham, Oregon
Terri L. Levien, PharmD Clinical Associate Professor Pharmacotherapy Department College of Pharmacy
Washington State University Spokane Spokane, Washington
David Nissen, PharmD Pharmacy Informatics
Missouri Baptist Medical Center St. Louis, Missouri
Lindsay B. Palkovic, PharmD, BCPS Assistant Professor of Clinical Pharmacy Philadelphia College of Pharmacy University of the Sciences in Philadelphia Philadelphia, Pennsylvania
Puja Patel, PharmD
Drug Information Resident 2009-2010
Mercer University and Solvay Pharmaceuticals Atlanta, Georgia
Karen J. Tietze, BS, PharmD Professor of Clinical Pharmacy
Department of Pharmacy Practice and Pharmacy Administration
Philadelphia College of Pharmacy University of the Sciences in Philadelphia Philadelphia, Pennsylvania
Bradley M. Wright, PharmD, BCPS
Assistant Clinical Professor of Pharmacy Practice Harrison School of Pharmacy
Auburn University Mobile, Alabama
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Introduction
...Mosby’s Pharmacy Review for the NAPLEX®reflects the unique attributes and dynamic role of the pharmacist in healthcare. The main objective of the text is to provide a useful, current, and comprehensive review of relevant pharmacy topics to the candidate in preparation for the NAPLEX®examination.
Although this text is for use primarily by NAPLEX® candidates, the concise format of the materials would make an excellent review for pharmacy students, pharmacy instructors, or for practicing pharmacists. Users of this guide will benefit from the review of a variety of topics relating to the science and art of pharmacy practice, including general reviews of medication
treatments for commonly encountered disease states and therapeutic areas. Candidates will benefit from keeping this book handy as they enter practice to provide a quick go-to reference regarding pharmaceutical calculation methods, patient counseling, and more.
Key features of this review include:
Over 1,600 NAPLEX®-oriented study questions. An easy to follow outline format for each chapter to organize and quickly overview each area of importance.
Pharmacist-oriented questions at the conclusion of each chapter include thorough rationales at the end of the book to aid in comprehensive review and study. The rationales help ensure comprehension and understanding of the material, rather than focus on direct memorization or rote review.
Patient-based review questions within the therapeutic review chapters are presented with an emphasis on appropriate patient counseling by the pharmacist.
Electronic flashcards and two mock timed examinations on the enclosed CD-ROM allow the student to test comprehension and to demonstrate competency under testing conditions. The NAPLEX®s focus on three areas of pharmaceutical practice is accurately reflected in the CD-ROM content.
How to Use This Book
It is best for a candidate to approach preparation for the NAPLEX®in a logical and orderly manner, with time given to consistent review of all areas of importance to the examination. The format of this text will help the student with his or her review and organization of study. The subject matter, including patient-based cases, will address all areas of the NAPLEX®competency statements, in roughly the same proportion that they are represented on the NAPLEX®examination. The three main areas of study are:
Area One: Assure Safe and Effective Pharmacotherapy and Optimize Therapeutic Outcomes
Area Two: Assure Safe and Accurate Preparation and Dispensing of Medications
Area Three: Provide Health Care Information and Promote Public Health
After a thorough review of the text contents, the student can use the CD-ROM to test medication familiarity and competency under simulated test circumstances. A well-prepared student who has studied to learn and understand the material will be able to display his or her knowledge and will enhance his or her potential for licensure.
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Contents
...1 Preparing for the NAPLEX® . . . 1
SECTION I: PHARMACEUTICAL
PRACTICE
2 Pharmaceutical Calculations . . . 33 Compounding . . . 18
4 Drug Information Resources . . . 27
5 Dispensing . . . 37
6 Patient Education . . . 56
7 Herbs and Dietary Supplements . . . 67
8 Laboratory Tests . . . 79
SECTION II: PHARMACOTHERAPY
IN PRACTICE
9 Antiinfective Agents . . . 8710 Cardiovascular Disorders . . . 103
11 Dermatologic Disorders . . . 132
12 Common Endocrinologic Disorders . . . 138
13 Gastrointestinal Disorders . . . 150
14 Geriatrics . . . 161
15 Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) . . . 175
16 Kidney Disorders . . . 180 17 Oncology . . . 186 18 Pain Management . . . 197 19 Psychiatric Disorders . . . 209 20 Respiratory Disorders . . . 223 21 Arthritis . . . 231 22 Seizure Disorders . . . 237
23 Women’s Health Issues . . . 247
24 Immunology and Vaccines . . . 258
25 Immunosuppressants . . . 266
SECTION III: CONSUMER-DIRECTED
HEALTHCARE
26 Nonprescription Products . . . 27127 Nutrition . . . 284
SECTION IV: MISCELLANEOUS
TOPICS IN PHARMACY PRACTICE
AND SCIENCE
28 Basic Pharmacokinetics . . . 289 29 Pharmacogenomics . . . 294 30 Toxicology . . . 299Appendix A
Drug Interactions . . . 305Appendix B
Federal Pharmacy Law . . . 308Appendix C
Foreign Pharmacy Graduate Equivalency Examination . . . 311Answers and Rationales . . . 313
Index . . . 385
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Preparing for the NAPLEX
®
CHAPTER
1
...
GENERAL INFORMATION
NAPLEXThe North American Pharmacy Licensure Exam (NAPLEX) is the clinical aptitude test developed by the National Association of Boards of Pharmacy (NABP) and administered to pharmacy graduates to assess the competency of candidates for pharmacy practice. It is a requirement to obtain pharmacy licensure in all 50 states.
MPJE
The Multistate Pharmacy Jurisprudence Examination (MPJE) is the examination developed by the NABP to test the candidate’s competency and knowledge of federal and state pharmacy law. The questions are customized to the specific law in each state. It is required for a pharmacy license by 44 states and the District of Columbia.
REGISTRATION
Candidates wishing to register for the NAPLEX with or without the MPJE must contact the board of pharmacy in the state they are seeking licensure or their school of pharmacy and complete a paper examination registration form for each examination. Candidates may also
choose to register online for the NAPLEX or MPJE at www.napb.net. Candidates should check the website to see if their state participates in online registration.
Candidates may submit their registration, paper or online, before graduation; however, the state board of pharmacy will authorize eligibility only after all graduation requirements have been met.
The NAPLEX and MPJE may be taken on the same day, if time permits; however, it may be beneficial to take the examinations on separate days due to the diversity of the material.
FEES
Examination fees:NAPLEX: $465 per examination
MPJE: $185 per examination
For those who wish to change their appointments, an additional fee of $50 will be charged. Candidates who withdraw from taking the NAPLEX will receive a partial refund of $140; those who withdraw from taking the MPJE will receive a partial refund of $65. Cancellations or
rescheduling the exam must be done at least two business days before the scheduled appointment.
Fees are payable to the National Association of Boards of Pharmacy or NABP and submitted in the form of a money order, bank draft, or certified check.
Personal check or cash is not accepted. After registration, candidates will receive an authorization to test (ATT) letter, which confirms the candidate’s eligibility by the state board of pharmacy. Upon receipt, candidates can schedule their
appointments for examination and have one year to do so. The ATT and application expires after one year.
The NABP website, www.nabp.net, can provide the most current information.
ANSWER FORMAT OF THE NAPLEX
The computer-adaptive NAPLEX examination consists of 185 multiple-choice questions; however, only 150 questions are scored. The remaining 35 are considered pretest questions, which have no impact on the final score. These questions are used to help develop future tests. Because no indication is given to determine the scored questions versus the nonscored questions, it is to test-takers’ advantage to answer all questions to the best of their knowledge.
The test also uses case/scenario-based format (i.e., patient profiles) and K-type multiple choice questions in which three choices are given and candidates select from five combinations of those three choices:
I. Choice 1 II. Choice 2 III. Choice 3 A. I only B. III only C. I and II D. II, III E. I, II, III
TEST STRUCTURE OF THE NAPLEX
The NAPLEX has three core areas:1. Ensure safe and effective pharmacotherapy and optimize therapeutic outcomes (approximately 54% of the exam).
2. Ensure safe and accurate preparation and dispensing of medications (approximately 35% of the exam).
3. Provide health care information and promote public health (approximately 11% of the exam).
Candidates may refer to the NAPLEX blueprint for more detailed dissection of the topics covered on the examination at www.nabp.net.
If the candidate does not pass the exam, he/she may retake the exam after 91 days for the NAPLEX and after 30 days for the MPJE.
ADMINISTRATION PROCESS
NAPLEXThe NAPLEX has 185 questions to be taken in a 4 hour and 15 minute time period. There is an optional 10 minute break after approximately two hours of testing time.
The test is presented in a computer-adaptive testing format, which means that each answered question will determine the difficulty of the next. A correctly answered question in a series will be followed by a harder question. An incorrect response will be followed by an easier question.
Every question must be answered in the order it is presented. The test-taker cannot return to previous questions and change answers, so all responses are final. Due to the adaptive nature of the exam, questions also cannot be skipped because each response determines the next question.
MPJE
The test consists of 90 questions; only 60 are scored. The exam is to be taken in two hours with no break.
TEST TAKING STRATEGY
Arrive to the testing center at least 30 minutes before the examination to allow time to check-in.
Take a snack for the 10-minute break during the NAPLEX.
Take proper identification (refer to candidate bulletin).
Relax the night before the exam and eat a nutritious breakfast the morning of the examination.
Although there is no penalty for guessing, you still want to make your best effort to choose a correct response.
Make educated guesses. If you can rule out one or more answer choices, you have a better chance of selecting the right answer.
Limit your time on any one question; as a general rule of thumb, be halfway through the NAPLEX by the 10 minute break.
Use various study guide materials, including text books, flashcards, class notes, and practice tests. Take a full-length practice test before the
examination.
Do not try to “cram” new material. Create a study schedule that allots adequate time for the various sections of the NAPLEX.
SCORE RESULTS
NAPLEXThe scaled NAPLEX scores range from 0 to 150 with a minimally acceptable level of performance on the examination reflected by a score of 75. To obtain a score, the candidate has to complete at least 162 questions. Test scores are not given directly to the candidate; instead, they are forwarded by the NABP to the board of pharmacy from which the candidate is seeking licensure.
Depending on the state, candidates may transfer their scores to more than one state. Candidates should check the website (www.nabp.net) about the score transfer program. The state to which they wish to transfer their scores should also be contacted for more information.
MPJE
The minimum acceptable passing score on the MPJE scale is 75. To obtain a score, the candidate has to complete at least 77 questions. MPJE scores cannot be transferred between states. Candidates must take the law portion for each individual state in which they are seeking licensure.
THE PRE-NAPLEX
The NABP also offers the pre-NAPLEX. It is designed to familiarize the test-taker with the testing experience. The pre-NAPLEX is the only practice exam written and developed by the NABP.
There are 50 questions on the pre-NAPLEX and two forms are available. The cost for each practice
examination is $50. The candidate must register with the website and set up a username and password. Each candidate may take the pre-NAPLEX two times but must complete the first test before starting another one and pay for each test. The test may be taken with any computer with Internet access, including at home, a school, a library, and at any time. The scores are scaled and interpreted similar to the NAPLEX.
NAPLEX AND MPJE REGISTRATION BULLETIN
A free bulletin regarding the NAPLEX and MPJE is offered to all candidates. Topics covered include registration procedures, testing appointment information, NAPLEX and MPJE administration, NAPLEX and MPJE score results, the pre-NAPLEX, and NAPLEX score transfer information. It is available online at http://www.nabp.net/ ftpfiles/bulletins/NAPLEXMPJE.pdf or through your state board of pharmacy.S E C T I O N
I
PHARMACEUTICAL PRACTICE
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CHAPTER
2
...
SYSTEMS OF MEASURE
Summary of conversion between metric, apothecaries’ and avoirdupois systems:
Note that in the apothecaries’ and avoirdupois systems there is only one common unit of measure, the grain. The other measurement units carry different values when comparing the systems. When converting between the two, the pharmacist should convert the value down to the grain amount in the one system, then convert to the other system.
Per the United States Pharmacopeia, 1 grain¼ 64.8 mg. METRIC SYSTEM
Mass ¼ gram (g) Length ¼ meter (m) Volume¼ liter (L)
¼ 1 cubic centimeter (cc) equals approximately 1 milliliter (mL) and weighs 1 g
Prefixes
kilo- 103 1 thousand (1000) times the basic unit hecto- 102 1 hundred (100) times the basic unit deka- 10 1 ten (10) times the basic unit deci- 101 1 tenth (0.1) times the basic unit centi- 102 1 hundredth (0.01) times the basic unit milli- 103 1 thousandth (0.001) times the basic unit micro- 106 1 millionth times the basic unit
nano- 109 1 billionth times the basic unit pico- 1012 1 trillionth times the basic unit
APOTHECARIES’ SYSTEM
Volume (fluid)
60 minims ¼ 1 fluid drachm (or dram)
8 drams ¼ 1 fluidounce
16 fluid ounces ¼ 1 pint
2 pints ¼ 1 quart
8 pints (4 quarts)¼ 1 gallon
Mass (weight)
12 ounces ¼ 1 pound
8 drams (480 grains) ¼ 1 ounce (apothecaries’)
1 drams ¼ 27.34375 grains
1 dram ¼ 1.772 grams
3 scruples ¼ 1 dram
20 grains ¼ 1 scruple AVOIRDUPOIS SYSTEM
A system of masses based on a pound weighing 16 ounces mostly commonly used in the United States for
commercial purposes.
Volume
1 fluid ounce ¼ 8 fluidram
Mass
437:5 grains ¼ 1 ounce 28:349523 grams ¼ 1 ounce
16 drams ¼ 1 ounce ðavoirdupoisÞ 16 ounces ¼ 1 pound ðlb:Þ
UNITS OF AMOUNT OF SUBSTANCE
1 Mole¼ Molecular Weight in grams or Relative Molecular Mass in grams
1 Molar solution¼ Gram Molecular Weight or Relative Molecular Mass in grams in 1 Liter
1 mol¼ 1000 millimols (normally written as 1000 mmol) 1 millimole¼ 1000 micromoles
1 micromole¼ 1000 nanomoles
1 mol / liter¼ 1 mmol / mL, 1 mmol / liter ¼ 1 micromole / mL Millimole (mmol): A millimole (mmol) is a molecular weight expressed in milligrams.
The number of millimoles of a substance is calculated by dividing the number of milligrams of a substance by the molecular weight (MW) of the substance:
mmols¼ mg/MW
RATIO AND PROPORTIONS
RATIOA ratio is a comparison of two numbers. In pharmacy calculations, a ratio can be used to express strength of drug concentration.
Example: A 1:25 solution of wintergreen oil means that 1 mL of wintergreen oil is contained in each 25 mL of solution.
PROPORTIONS
A proportion represents the equality between two ratios. A proportion is an equation with a ratio on each side. It is a statement that two ratios are equal. This mathematical concept is often used in community pharmacy.
Example:
If 5 tablets contain 1625 mg of acetaminophen, how many tablets should contain 2925 mg?
Solution: 5ðtabletsÞ ¼ 1625 milligrams XðtabletsÞ ¼ 2925 milligrams X ¼ 9 tablets; answer 5 tablets 1625 mg ¼ X tablets 2925 mg X¼ 9 tablets
Relevant measurements and conversions
1 in ¼ 2.54 cm 1 m ¼ 39.37 in 1 kg ¼ 2.2 lb 1 g ¼ 15.4324 gr (round to 15.4 gr) 1 fl oz.¼ 29.5729 mL (round to 29.6 or 30 mL)DIMENSIONAL ANALYSIS
Dimensional analysis is a method of manipulating units to solve mathematical equations. The process allows you to cancel out unwanted units leaving only those units you want your answer to be expressed as.
Example:
A pharmacist wants to know how many inhalers should be dispensed to a patient to provide a 60-day
supply of fluticasone. The recommended daily dose is 250 mcg twice daily. The commercial inhaler delivers 220 mcg per metered dose and contains 60 metered inhalations.
Solution:
220 mcg 2 (twice daily) ¼ 440 mcg/day
440 mcg 1 inhalation 1 inhaler
60 days ¼ 2 inhalers day 220 mcg 60 inhalations
The pharmacist should dispense 2 inhalers for a 60-day supply.
INTERPRETATION OF MEDICATION ORDERS
Example 1:A prescription for prednisone 5 mg should be taken as follows:
2 tablets three times daily the first day; 1 tablet three times daily on the second day; 1 tablet twice daily for 7 days; and 1 tablet daily thereafter.
How many tablets should be dispensed for a 30-day supply?
Solution: Dispense 44 tablets in total
Example 2:
A prescription is to be taken as follows: “1 tablespoon ac and hs for 7 days.” What is the minimum volume that should be dispensed?
Solution:
achs¼ before meals and at bedtime 1 tablespoon¼ 15 mL
Patient needs to receive four doses per day for 7 days. 15 mL 4 doses 7 days ¼ 420 mL
DOSAGE BASED ON DROPS
Certain medications that are administered or dispensed to a patient come in the form of liquids and are administered as drops. This section provides practice for calculations for these types of prescriptions.
If a pharmacist counted 30 drops of a drug in filling a graduated cylinder to the 1.5 mL mark, how many drops per milliliter did the dropper deliver?
Solution:
30 dropsðgttÞ
X gtts ¼
1:5 mL 1 mL X ¼ 20 drops per mL; answer
PERCENTAGE AND RATIO STRENGTH CALCULATIONS
EXPRESSED AS V/V, W/W, AND W/V
Certain prescriptions are expressed in weight/weight (w/w), volume/volume (v/v), and weight/volume (w/v) percentages. To properly process prescription orders of this nature, the pharmacist must be able to make conversions and calculations with these units. Concentration¼ quantity of solute divided by the
quantity of preparation.
V/V: If the solute and the preparation are expressed in the same units, then concentration is dimensionless. For example, 10 mL of alcohol dissolved in a sufficient quantity of water to make 40 mL of solution is
dimensionless: 10 mL/40 mL¼ 0.250 (or 25% v/v).
W/W: If the quantity of solute and of the preparation are expressed in the same units of weight, the concentration is dimensionless. If 10 g of charcoal are mixed with 65 g of another powder to make a total of 75 g, the charcoal concentration is 10 g/75 g¼ 0.133 by weight (or 13.3% w/w).
W/V: When a solute is measured by weight and the solution by volume, concentration is not dimensionless. If 1.25 g of NaCl is dissolved in sufficient water to make 55 mL of solution, the concentration is 1.25 g/55 mL¼ 0.0227 g/mL (w/v). The % w/v is expressed as #g/100 mL (e.g., 2.27% or 2.27 g/100 mL).
Example 1:
How many grams of drug should be used to prepare 120 grams of a 2% w/w solution in water?
Solution:
120 grams mixture 2 grams drug 100 grams drug ¼ 2:4 grams, answer
Example 2:
What is the percentage strength (w/v) of a solution of drug if 40 mL contain 5 grams?
Solution: 40 mL 5 grams¼ 100ð%Þ Xð%Þ X ¼ 12:5%; answer
PPM AND PPB (PARTS PER MILLION AND PARTS PER BILLION)
When ppm or ppb is used as a designation for
concentration, some systems are w/w, some are v/v and some are w/v. Concentration is always a ratio or fraction in w/w and v/v situations. Weight by volume (w/v) concentrations are always defined in terms of grams and milliliters. The same default rules are followed as for percentage systems.
Example:
Express 2 ppm of ferrous gluconate in water in percentage strength and ratio strength.
Solution:
2 ppm¼ 2 parts in 1,000,000 parts ¼ 1:500,000 ratio strength
0.0002% percentage strength
DILUTION, CONCENTRATION, AND ALLIGATION
DILUTION OF AN INGREDIENTDilution is the addition of diluent to the ingredient or an admixture of the ingredient with solutions to achieve a lower concentration of solution.
Example:
A 1:5000 dilution of drug A is requested. If 1 mL of drug A injection 1:200 is mixed with sterile water for injection, how many mL of water will be needed?
Solution: 1 2001 mL¼ 1 5000ð ÞX 0.005¼ 0.0002(X) 25 mL¼ X 25 mL 1 mL ¼ 24 mL, answer CONCENTRATION OF AN INGREDIENT
Concentration is the addition of an active ingredient or evaporation of the diluent from an active ingredient to create a more concentrated solution.
Example:
How many grams of coal tar containing 25% (w/w) should be added to petrolatum to prepare 240 grams of coal tar containing 15% (w/w)?
Solution:
The coal tar (active ingredient) is added to a diluent (petroleum) currently containing no coal tar.
25% 15% ¼
240 grams X grams X¼ 143.7 grams
144 grams of coal tar, answer ALIQUOT METHOD (ALLIGATION)
Alligation is a method that is particularly useful when mixing two or more preparations of known strengths to prepare a mixture of an intermediate desired strength. The final mixture will be an average of the individual strengths, which are calculated as proportional parts.
Alligation Alternate and Alligation Medial are methods that can be used to solve any type of dilution or
concentration problem, including concentrations
expressed in mg/mL, ratios, mixtures of liquids of known specific gravities, etc. The strengths of all preparations being mixed and the final mixture are expressed in a common denomination (of weight, volume, percentage, etc.) when setting up the alligation equation. When diluting a preparation, the strength of the diluent is considered to be 0%. When increasing the strength of a given mixture by adding more drug/active ingredient, the strength of the active ingredient to be added is
considered to be 100%. A final proportion allows a correlation between the parts and any specific denomination needed.
Example 1:
A pharmacist has a 60% solution and a 15% solution. She needs a 40% solution to compound a medication. What is the proportion of the 60% and 15% solutions that would make a 40% solution? This example will use the process of Alligation Alternate to calculate the quantities of each mixture needed to make the final mixture of the desired strength:
Solution:
60% 25 60 40 ¼ 20
40% 15 40 ¼ 25
15% 20 parts 25þ 20 ¼ 45
25 parts of the 60% solution combined with 25 parts of 15% solution would yield 45 parts of a 40% solution.
ISOTONIC SOLUTIONS
Osmosis occurs when a solvent (e.g.,water) passes through a semipermiable membrane from a
low-concentration solution into a high-low-concentration one, with the result that the concentrations become equalized. The pressure that causes this occurrence is known as osmotic pressure.
A solution that exerts the same osmotic pressure as a specific body fluid is known as isotonic. If the solution exerts an osmotic pressure lower than that of specific body fluid, the solution is hypotonic. If the actual solution exerts an osmotic pressure higher than that of specific body fluid, the solution is considered hypertonic.
Example:
How much sodium chloride is needed to adjust the following prescription to isotonicity? (E value [sodium chloride equivalents] for zinc sulfate is 0.15)
Zinc sulfate 2%
NaCl q.s.
Purified water q.s. 60 mL Make isotonic solution Solution:
If sodium chloride is only being used to provide the 60 mL isotonic solution: 60 mL 0.9% ¼ 0.54 g (or 540 mg) Step 1: 60 mL 2% ¼ 1.2 g (or 1200 mg) of zinc sulfate
required to fill the prescription
Step 2: 1200 mg is equivalent to 1200 0.15 ¼ 180 mg of sodium chloride
Step 3: 540 mg 180 mg ¼ 360 mg (or 0.36 g), answer
ELECTROLYTE SOLUTIONS
Electrolyte solutions are used to treat fluid and electrolyte disturbances. They may be prepared as oral solutions, syrups, dry granules intended to be dissolved in water or juice to make an oral solution, or oral tablets or capsules, and they are also commonly prepared as intravenous infusions.
To convert electrolytes in solution (expressed as milliequivalents [mEq] per unit volume to weight per unit volume or vice versa), the following calculation may be used:
mEq¼ mg Valence
Atomic; molecular; or formula weight mg¼mEq Atomic; molecular; or formula weight
Valence
Example:
How much calcium chloride (CaCl22H2O) is required to prepare 100, 1 mL ampules containing 10 mEq per mL? (mw¼ 147) Solution: 100 mL 10 mEq=mL ¼ 1000 mEq 1 mEq¼147 mg 2 ¼ 73:5 mg 1 mEq 73:5 mg¼ 1000 mEq X ¼ 73; 500 mg X¼ 73:5 g, answer
TPN CALCULATIONS
Total parenteral nutrition (TPN) provides all of the patient’s daily nutritional requirements and generally contains dextrose (carbohydrate), amino acids (protein source), vitamins, trace minerals, electrolytes, and fat emulsions. TPN solutions may also include insulin and occasionally therapeutic drugs. The amount of protein, dextrose, and fat are calculated based on the patient’s daily kcal (calories) needed and available stock solutions. Other ingredients do not contain calories.
Example:
A patient needs 1600 kcal/day. The physician has ordered that the patient receive 65% of the daily calories (kcal) from carbohydrates, 10% from protein, and 25% from fat.
Calculate the amount (volume) needed to supply the dextrose, protein, and fat calories from these pharmacy stock solutions:
Dextrose 65%, amino acid 10%, fat 25%
First, determine how many kcal the patient needs from each component:
1600 kcal 65% ¼ 1040 kcal from dextrose 1600 kcal 10% ¼ 160 kcal from protein 1600 kcal 25% ¼ 400 kcal from fat Next, convert these kcals into grams:
1040 kcal 1 gram=3:4 kcal ¼ 305:9 grams dextrose 160 kcal 1 gram=4 kcal ¼ 40 grams protein 400 kcal 1 gram=9 kcal ¼ 44 grams fat
Then, calculate how many milliliters are needed from each stock solution:
305.9 grams 100 mL/ 65 grams ¼ 470.6 mL from dextrose 65% 40 grams 100 mL/ 10 grams ¼ 400 mL from amino
acid 10%
44.4 grams 100 mL/ 25 grams ¼ 177.6 mL from fat 25% NOTE:
Carbohydrate contains 3.4 kcal/g Amino acid contains 4 kcal/g Fat contains 9 kcal/g
CALCULATION OF DOSES
There are a variety of ways to determine doses of drugs including by age, body weight, surface area, creatinine clearance, and other pharmacokinetic parameters.
Table 2-1
Valences and Atomic Weights of Select Ions
Ion Formula Atomic/FormulaWeight Valence
Aluminum Al3þ 27 3 Ammonium NH4þ 18 1 Acetate C2H3O2 59 1 Bicarbonate HCO3 61 1 Calcium Caþ2 40 2 Carbonate CO32 60 2 Chloride Cl 35.5 1 Citrate C6H5O73 189 3 Ferrous Fe2þ 56 2 Ferric Fe3þ 56 3 Gluconate C6H5O3 195 1 Lactate C3H5O3 89 1 Lithium Liþ 7 1 Magnesium Mg2þ 24 2 Phosphate (mono) H2PO4 97 1
Phosphate (di) HPO42 96 2
Potassium Kþ 39 1
Sodium Naþ 23 1
Sulfate SO4
2 96 2
From Zatz J: Pharmaceutical Calculations, ed 4, Hoboken, NJ, 2005, John Wiley & Sons, Inc., p. 267.
CREATININE CLEARANCE
When using the below equations, two factors to consider are (1) the serum creatinine is at steady state and (2) the weight, gender, and age of the individual reflect normal muscle mass.
Cockcroft-Gault equation
To estimate renal function for the purpose of drug dosing, creatinine clearance should be measured or estimated.
For males:
CrCl¼ð140 Patient
0s age in yearsÞ Body weight in kg
72 Serum creatinine in mg=dL For females:
CrCl¼ 0:85 CrCl determined using formula for males If the individual is obese or not within 30% of their ideal body weight, other methods of calculating creatinine clearance should be used. Ideal body weight (IBW) or adjusted body weight (ideal body weight plus 40% of obese weight) instead of actual body weight in the Cockcroft-Gault equation will provide a better estimate of creatinine clearance.
IBW for males in kg¼ 50 þ (2.3)(Height in inches > 60) IBW for females in kg¼ 45 þ (2.3)(Height in inches > 60)
BODY SURFACE AREA
The practioner may need to take into account body surface area as a possible variable when determining drug dosage (e.g., chemotherapy).
Body Surface Area (BSA) – The Mosteller Formula: BSAðm2Þ ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi HeightðcmÞ Weight ðkgÞ
3600 r
The average BSA of an adult is 1.73 m2.
CALCULATIONS FOR PEDIATRIC DOSES
Various pediatric formulas have been used historically to calculate APPROXIMATE pediatric dosages.
Young’s rule, based on age: Age
Ageþ 12 Adult dose ¼ Dose for child Fried’s rule for infants:
Ageðin monthsÞ
150 Adult dose ¼ Approx: dose for infant
Clark’s rule, based on weight: Weightðin lbÞ Adult dose
150 ¼ Dose for child
BSA approximation of child’s dose: Child BSA
1:73 m2 Adult dose ¼ Approx: dose for child
STOCK SOLUTIONS
A stock solution, commonly referred to as bulk bottle, is a large volume of a reagent (in chemistry) or in this case, medication. These stock solutions can be prepared by a manufacturer or compounded in the pharmacy.
Pharmacists typically take stock solutions and use them to prepare weaker solutions of medications or chemicals for laboratory or clinical use.
Example:
How many mL of a 0.5% gentian violet stock solution is needed to prepare 1 pint of a 1:2000 solution?
Solution:
Step 1: Determine the quantity of the final solution: 1 pint¼ 946 mL, so 1 g 200 mL¼ X grams 946 mL X¼ 0:473 grams
Step 2: Determine the amount of available solution needed to obtain the determined quantity (0.5% gentian violet solution contains 0.5 grams in 100 mL of solution):
0:5 g 100 mL¼
0:473 grams X mL
X¼ 94:6 mL; estimate 95 mL
RECONSTITUTION OF DRY POWDERS
Many drugs (antibiotics, steroids, and biologics) that are not stable in solution are prepared as dry-filled solids or lyophilized powders. Prior to use, these dry powders must be reconstituted as a solution with a suitable diluent in the proper volume to give specified concentration (usually provided in the package insert). Occasionally, the physician may prescribe a final concentration different from the one provided by the manufacturer. Also, in some cases, the pharmacist needs to determine if the powdered drug contributes to the final volume of the reconstituted solution before modifying the label instructions.
Example:
The package information of a vial containing 30 million units of penicillin G potassium specifies that when the appropriate amount of sterile solvent is added to dry powder, the resulting concentration is 500,000 units per mL. How many milliliters of sterile water for injection are needed to prepare the following solution?
(Note: the powder accounts for 8 mL of the final volume) Penicillin G potassium 30,000,000 units
Sterile water for injection
Provide a solution containing 500,000 units per mL 500; 000 units 30; 000; 000 units¼ 1 mL X mL X¼ 60 mL 60 mL 8 mL ¼ 52 mL, answer
INTRAVENOUS INFUSIONS, PARENTERAL
ADMIXTURES, AND FLOW RATES
Intravenous infusions are large volumes of sterile, aqueous preparations administered intravenously (through a vein) over an extended period of time.Example:
An order is written for 25,000 units of heparin in 250 mL of D5W to infuse at 2000 units/hr. What is the correct rate of the infusion (in mL/hr)?
Solution:
Concentration of IV¼Total amount of drug Total volume
IV rate ¼ Dose desired Concentration of IV
Concentration of IV¼25;000 units of heparin 250 mL of D5W Concentration of IV¼ 100 units=mL of heparin
IV rate ¼2000 units=hr 100 units=mL IV rate ¼ 20 mL=hr
Parenteral admixtures are a sterile preparation that involves the combination of one or more drugs to large-volume.
Example:
A patient weighs 170 pounds. A pharmacist receives a prescription order for 0.25 mg amphotericin B per kilogram body weight. How many milliliters of a 25 mg/ 10 mL solution are needed to supply the dose, which will then be diluted in 500 mL of 5% dextrose?
Solution: 170 lb 2:2 lb¼ 77 kg patient 0:25 mg 77 kg ¼ 19:25 mg dose needed 25 mg 19:25 mg¼ 10 mL X mL X¼ 7:7 mL, answer
Calculating IV flow or drip rates are necessary to ensure that the patient is receiving the desired amount of drug that was ordered.
Example:
If 20 mg of drug is added to a 750 mL parenteral fluid, what flow rate, in millilters per hour, will deliver 2 mg of drug per hour? Solution: 20 mg 2 mg ¼ 750 mL X mL
X¼ 75 mL per hour, answer
References
Ansel H, Stoklosa M: Pharmaceutical Calculations, ed 12, Baltimore, MD, 2005, Lippincott Williams & Wilkins. Bhatt SHL: Aminoglycoside Pharmacokinetics and
Therapeutics, MCPHS Boston Campus, MA, 2006, White Hall.
Institute of the Certification of Pharmacy Technicians (ICPT): ExCPT Exam for the Certification of Pharmacy Technicians. Available at http://www.nationaltechexam. org/pdf/math_questions-answers070618.pdf, Accessed December 24, 2008.
London, Eastern and South East Specialist Pharmacy Services. Available at http://www.londonpharmacy.nhs. uk/educationandtraining/prereg/supportMaterial/ calculations/download/Calculations%20WorkBook% 202005.pdf, Accessed December 24, 2008.
Pearson J, Powers M: Systematically Initiating Insulin. The Staged Diabetes Management Approach, Diabetes Educ 32(Suppl 1):23s, 2006.
Shargel L: Applied Biopharmaceutics & Pharmacokinetics, New York, 2005, McGraw-Hill Medical Publishing Division, pp 43–46.
Zatz J: Pharmaceutical Calculations, ed 4, Hoboken, NJ, 2005, John Wiley & Sons, Inc, pp 30–33.
Mosteller RD: Simplified Calculation of Body Surface Area, N Engl J Med 317:1098, (letter) 1987.
REVIEW QUESTIONS
(Answers and Rationales on page 313.)
1. A patient is prescribed 10 mEq of potassium daily. The source of potassium chloride in the pharmacy is 5 mEq/mL in 1 mL vials. How many vials per day is needed for the patient?
a. 0.5 vial b. 1 vial c. 2 vials d. 1.5 vials
2. How much elemental iron is present in every 150 mg of ferrous sulfate (FeSO47H2O)? (Atomic weights are iron¼ 55.9; sulfur ¼ 32.1; oxygen¼ 16.0; and hydrogen ¼ 1.0. Iron has valences ofþ2 and þ3) a. 25 mg b. 30 mg c. 48 mg d. 54 mg e. 60 mg
3. A 130-lb patient has a creatinine clearance rate of 40 mL/min. Assuming Drug X is eliminated exclusively by renal mechanisms, what maintenance dose should be administered if the normal
maintenance dose is 3 mg/lb of body weight? a. 50 mg
b. 100 mg c. 150 mg d. 200 mg e. 250 mg
4. An IV medication is available as 3.5 g/ 500 mL with a strength calculation of 0.25 mg/kg/min is
prescribed to a 130-lb patient. What is the infusion rate in mL/hour?
a. 2.1 mL/ hr b. 126.6 mL/ hr c. 278.6 mL/ hr d. 6,203.4 mL/ hr
5. Which of the following is an invalid DEA number? a. BT5555555
b. DB1294658 c. AR7532648 d. MA2643713
e. All of the above are valid
6. How many quarts are in two gallons? a. 2 quarts
b. 4 quarts c. 8 quarts d. 16 quarts
7. How many fluid ounces are in a quart? a. 4 fluid ounces
b. 8 fluid ounces c. 16 fluid ounces d. 32 fluid ounces
8. How many teaspoons are in one pint? a. 31.5
b. 47.3 c. 94.6 d. 104.2
9. A patient is prescribed 20 mEq of potassium chloride daily. The source of potassium chloride in the pharmacy is 2 mEq/ mL in 20 mL vials. How many mL per day are needed for this patient? a. 1 mL
b. 2 mL c. 10 mL d. 20 mL
10. A patient is prescribed 10 mEq of potassium chloride daily. The source of potassium chloride in the pharmacy is 2 mEq/ mL in 20 mL vials. How many mL per day are needed for this patient? a. 0.5 mL
b. 1 mL c. 5 mL d. 10 mL
11. How much sodium chloride is needed to make an isotonic 100 mL solution?
a. 0.45 g b. 0.90 g c. 1.32 g d. 1.53 g
12. What volume of diluent (assume sterile water) is needed to make an isotonic solution from 0.45 g of sodium chloride?
a. 25 mL b. 50 mL
c. 100 mL d. 125 mL
13. The ratio strength of a solution is 1:900 (w/v). What is the percent weight by volume [(w/v)%] of the solution?
a. 0.1% b. 1.1 % c. 0.9%
d. 9%
14. The ratio strength of a solution is 1:5000 (w/v). What is the percent weight by volume [(w/v)%] of the solution?
a. 0.02% b. 2 % c. 0.8%
d. 8%
15. A vial of tobramycin sulfate contains 40 mg of drug per mL of injection. A patient was given 0.5 mL. How much tobramycin sulfate was administered? a. 10 mg
b. 20 mg c. 30 mg d. 40 mg
16. How many days will the following prescription supply? Rx
Penicillin VK suspension 250 mg/5 mL Sig. 1 tsp. qid t.a.t. disp 200 mL a. 7 days
b. 10 days c. 14 days d. 21 days
17. A medication is available in a 200 mg/5 mL vial. An Rx calls for 150 mg bid 10d.
How many milliliters are needed for a single day? a. 5 mL
b. 7.5 mL c. 10 mL d. 75 mL
18. A medication is available in a 200 mg/5 mL multiple-use vial. An Rx calls for 300 mg bid 10d.
How many vials are needed for the full course? a. 15 vials
b. 30 vials c. 60 vials d. 75 vials
19. JK is a 42 year-old woman who has a prescription for 32 mEq of oral potassium chloride. However, your pharmacy only has 600 mg controlled-release potassium chloride tablets in stock. How many tablets are required each day to provide this dose? (MW¼ 75) a. 8 b. 3 c. 2 d. 4 e. 6
20. If a patient has a temperature of 102.2F, what is the patient’s temperature in degrees Celsius?
a. 37.6C b. 38.4C c. 39C d. 40.1C
21. If 500 mL of a 15% (v/v) solution of methyl salicylate in alcohol is diluted to 1500 mL, what will be the percentage strength (v/v)?
a. 225%
b. 5%
c. 45% d. 0.45%
22. A medication is available in a 150 mg/5 mL vial. An Rx calls for 300 mg bid 10d.
How many mL are needed for a single dose? a. 5 mL
b. 10 mL c. 50 mL d. 100 mL
23. What is the day supply for this prescription? Amoxicillin 125 mg/5 ml (100 ml) SIG: ss tsp tid a. 2 days b. 100 days c. 25 days d. 13 days e. 10 days
24. What is the percent weight by volume [%(w/v)] if 250 grams of dextrose is dissolved in 300 mL of water to make a final volume of 500 mL? a. 4.5%
b. 5%
c. 45.45% d. 50%
25. If a prescription reads “Dispense: XVIII capsules,” how many capsules should be dispensed? a. 12 tablets
b. 18 tablets c. 22 tablets d. 30 tablets
26. What total quantity of tablets should be dispensed for the following prescription?
Rx: Prednisone 5 mg Sig: 10 mg qid 2 days 10 mg tid 2 days 10 mg bid 2 days 5 mg tid 2 days
5 mg bid 2 days Then stop. Qty qs
a. 23 tablets b. 25 tablets c. 46 tablets d. 50 tablets
27. What quantity should be dispensed for the following prescription?
Rx: Prednisone 10 mg Sig: 2 tabs bid 3 days 1 tab bid 3 days 1 tab qd 3 days
1/2 tab qd 3 days Then stop. Qty qs
a. 9 tablets b. 10 tablets c. 22 tablets d. 23 tablets
28. How many grams of NaCl are there in 1000 mL of D5W/0.45% NaCl solution? a. 4.5 g
b. 0.6 g c. 0.45 g d. 0.25 g
29. How many grams of dextrose are in 1000 mL of D5W/ 0.45% NaCl solution?
a. 100 g b. 50 g c. 20 g d. 15 g
30. How many grams of dextrose are in 500 mL of a 10% dextrose solution?
a. 500 g b. 50 g c. 150 g d. 200 g
31. How many grams of NaCl are in 500 mL of 0.9% sodium chloride (NS) solution?
a. 5 g b. 2.5 g c. 4.5 g d. 1.5 g
32. How many milligrams of neomycin are in 25 mL of a 1% neomycin solution?
a. 250 mg b. 125 mg c. 400 mg d. 500 mg
33. How many grams of amino acids are in 500 mL of a 5% amino acid solution?
a. 2.5 g b. 22.5 g c. 25 g d. 50 g e. 10 g
34. A pharmacist has 25 mL of 0.5% gentian violet solution. What will be the final ratio strength if he or she dilutes this solution to 600 mL with purified water? a. 1:8 b. 1:200 c. 1:500 d. 1:1000 e. 1:4800
35. An order is written for 1 g of lidocaine in 250 mL of D5W to infuse at 60 mg/hr. What is the correct infusion in (mL/hr)?
a. 15 mL/hr b. 20 mL/hr c. 35 mL/hr d. 45 mL/hr
36. An order is written for 25,000 units of heparin in 250 mL of D5W to infuse at 17 mL/hr. How many units of heparin will the patient receive in 6 hours?
a. 10,200 units b. 40,000 units c. 10,800 units d. 20,400 units
37. An order calls for 2.5 million units of aqueous penicillin. How many milliliters are needed if the vial concentration is 500,000 units/mL?
a. 6 mL b. 2 mL c. 10 mL d. 5 mL
38. How many milliliters are needed for 5 million units of penicillin if the vial concentration is 1 million units per mL?
a. 15 mL b. 5 mL c. 10 mL d. 20 mL
39. Valproic acid syrup comes in a 250 mg/5 mL concentration. How many mg are present in 7.5 mL of solution?
a. 1000 mg b. 500 mg c. 375 mg d. 250 mg
40. How many milliliters of 250 mg/5 mL valproic acid syrup are needed for a 0.5-g dose?
a. 1 mL b. 5 mL c. 10 mL d. 15 mL
41. If a drug comes in a 250 mg/1.5 mL solution, how many milliliters are required for a 2 g dose? a. 1.5 mL
b. 2 mL c. 4.5 mL d. 6 mL e. 12 mL
42. How many grams of ampicillin are in 3 mL of a 500 mg/1.5 mL solution?
a. 1 gram b. 4 grams c. 3.5 grams d. 2 grams
43. How many milliliters contain 2.5 g of
cephalothin if the concentration of the solution is 1 g/4.5 mL?
a. 16.5 mL b. 13.5 mL c. 14.25 mL d. 11.25 mL
44. How many grams of iodine are in 4 mL of a 50% iodine solution?
a. 1 g b. 2 g c. 3 g d. 4 g
45. How many milliliters of a 50% dextrose solution are needed for a 7.5-g dextrose dose?
a. 7.5 mL b. 10 mL c. 15 mL d. 20 mL
46. How many grams of sodium are in 50 mL D5W solution?
a. 0 b. 1 c. 2.5 d. 3
47. The unit of weight measurement that is the same in both the apothecaries’ and avoirdupois systems is the? a. Dram b. Grain c. Ounce d. Pound e. Scrupple
48. One microgram equals one thousand (1000): a. Centigrams
b. Grams c. Kilograms d. Nanograms e. Milligrams
49. Calculate the drip rate for 120 mL of IV fluids to be given over a half hour via an IV set that delivers 15 gtt/mL. a. 13 gtt/min b. 25 gtt/min c. 60 gtt/min d. 33 gtt/min e. 50 gtt/min
50. If a patient is given IV fluids at a rate of 25 gtt/min over 1 hour, how much fluid will be administered? The drop factor is 15 gtt/ml.
a. 50 mL b. 100 mL c. 125 mL d. 200 mL e. 225 mL
51. In order to achieve better pain control, codeine phosphate 0.7 mL SC 1 is ordered for a patient. The injectable form of codeine phosphate is available in a concentration of 50 mg/mL. How much codeine will this patient receive in this dose? a. 20 mg
b. 30 mg c. 35 mg d. 60 mg e. 100 mg
52. Morphine is ordered for a patient, and the nurse gives him 1.9 mL from a vial with a concentration of 40 mg/2.5 mL. How much morphine was the patient given? a. 5 mg b. 10 mg c. 20 mg d. 30 mg e. 40 mg
53. The vial of hydromorphone that you have in stock has a concentration of 1.5 mg/0.5 mL. If the patient is given 0.7 mL, how much hydromorphone did she receive? a. 1. 8 mg b. 2.1 mg c. 2.2 mg d. 2.4 mg e. 3 mg
54. What is the concentration (in percent) of a solution containing 20 mEq of potassium chloride per 15 mL of liquid? (MW¼ 75) a. 10 b. 15 c. 20 d. 25 e. 2.5
55. Diazepam is to be administered by the IV route to an adult patient. It is given at a rate of 5 mg/min over 90 seconds. How much diazepam is given to this patient? a. 5 mg b. 6 mg c. 7.5 mg d. 8 mg e. 10 mg
56. How many milligrams of morphine were given to a patient who received 6.2 mL of a 5 mg/mL solution? a. 31 mg
b. 22 mg c. 25 mg d. 35 mg e. 46 mg
57. A nurse wants to give 300 mcg of levothyroxine IV to a patient, from a vial containing 0.4 mg/mL. How many milliliters should be given to
the patient? a. 0.6 mL b. 0.8 mL c. 1.0 mL d. 1.2 mL e. 7.5 mL
58. A patient is to take 2.6 mL of oral furosemide, and each teaspoon contains 40 mg. How much
furosemide will the patient be taking in their 2.6 mL dose? a. 20.8 mg b. 40 mg c. 33.1 mg d. 16.5 mg e. 24 mg
59. What is the percent weight=weight (%[w/w]) if 250 grams of dextrose is dissolved in 300 mL of water to make a final volume of 500 mL? a. 4.5%
b. 5%
c. 45.45% d. 50%
60. According to USP specifications, how many milligrams is equal to 1/2 grain?
a. 64.8 mg b. 32.4 mg c. 32.4 g d. 3.24 mg
61. If the adult dose of a drug is 200 mg, what is the estimated dose for a child with a BSA of 0.8 m2, using the BSA estimation method?
a. 92 mg b. 150 mg c. 50 mg d. 75 mg
62. If Lanoxin Pediatric Elixir contains 0.1 mg of digoxin per mL, how many mcg of digoxin are in 6 mL elixir?
a. 6 mcg b. 60 mcg c. 600 mcg d. 6000 mcg
63. What is the percentage of alcohol in a mixture of 200 mL of 95% v/v alcohol, 1000 mL of 70% v/v alcohol, and 200 mL of 80% v/v alcohol? a. 75%
b. 82% c. 0.75% d. 7.5%
64. A TPN order requires 500 mL of D5W. How many mL of D50W should be used if the D5W is not available?
a. 450 mL b. 550 mL c. 50 mL d. 25 mL
65. How much sodium chloride is needed to make the following prescription isotonic given E value for zinc sulfate is 0.15? Zinc sulfate 2% Sodium chloride q.s. Purified water q.s 60 mL a. 540 mg b. 1200 mg c. 180 mg d. 360 mg
66. How much elemental iron is present in 500 mg of ferrous sulfate (FeSO47H2O) with atomic weights are Fe¼ 55.9; sulfur ¼ 32.1; oxygen ¼ 16.0; and hydrogen¼ 1.0. Iron has valences of
þ2 and þ3)? a. 100.5 mg b. 167.7 mg c. 111.8 mg d. 120 mg
67. What will be the final ratio strength of a solution if one wishes to dilute 100 mL of 0.5% gentian violet solution to 1250 mL with purified water?
a. 1:500 b. 1:1000 c. 1:2500 d. 1:5000
68. How many beclomethasone (Qvar) inhalers should be dispensed to provide a 90-day supply? The recommended dose is 168 mcg BID. The commercial inhaler delivers 42 mcg per metered dose and contains 200 inhalations
a. 2 inhalers b. 3 inhalers c. 4 inhalers d. 5 inhalers
69. If 6.25 g of boric acid are dissolved in sufficient alcohol to make a total volume of 100 mL, what is the strength of boric acid in the solution in mg/mL? a. 62.5 mg/mL
b. 6.25 mg/mL c. 625 mg/mL d. 62.5 g/mL
70. If 50 mL of 4% (w/v) Xylocaine solution are added to 100 mL bag of D5W injection, what is the percentage strength (w/v) of Xylocaine in the final product?
a. 1%
b. 2.5% c. 1.3%
d. 2%
71. A blood glucose reading shows 200 mg% of glucose. Express this value in mg/mL.
a. 0.2 mg/mL b. 20 mg/mL c. 2 mg/mL d. 200 mg/mL
72. How many grams of solute are there in 250 g of a 1:50 w/w solution?
a. 50 g b. 5 g c. 0.5 g d. 5 mg
73. How many milligrams of drug are there in 50 mL of a 5% w/v solution?
a. 0.25 g b. 5 g c. 2500 mg d. 250 mg
74. How many milligrams of drug are there in 100 g of a 1:200 w/w mixture?
a. 500 mg b. 5 mg c. 5 g d. 5000 mg
75. How many mg of sodium bicarbonate (NaHCO2) contain 400 mg of sodium?
a. 1496 mg b. 1.496 mg c. 0.922 mg d. 922 mg
76. What is the percentage (based on weight) of Na in Na2CO3?
a. 21.7% b. 43.4% c. 4.34% d. 0.434%
77. How many milligrams of sodium chloride are there in a 2 mmol solution? (MW of NaCl¼ 58.5)
a. 117 mg b. 11.7 mg c. 1.17 mg d. 1.17 g
78. How many millimoles of calcium fluoride are present in 5 g? (MW of calcium fluoride¼ 78)
a. 0.641 mmol b. 6.41 mmol c. 64.1 mmol d. 64.1 mol
79. How many grams of KCl are needed to prepare 50 mmols solution? (MW of KCl¼ 74.6) a. 3730 mg
b. 37.30 mg c. 3.730 g d. 37.30 g
80. What is the percentage strength of 1:200 solution of oil in alcohol?
a. 0.5% v/v b. 0.005% v/v c. 5% v/v d. 0.5 mL
81. What is the percentage concentration of a 2:2000 solution of benzalkonium chloride?
a. 0.01% w/v b. 1% w/v c. 0.1% w/v d. 10% w/v
82. To make 100 mL of 1:1000 w/v solution, how many milligrams of NaHCO2are needed?
a. 10 mg b. 100 mg c. 0.1 mg d. 1 mg
83. If the reorder point for simvastatin 40 mg is 2 and the maximum is 5, how many bottles should be ordered if there is 1 bottle of simvastatin 40 mg? a. 0
b. 1 c. 4 d. 5
84. You have a bottle of 1 g amoxicillin powder for oral suspension. How many mL of purified water are needed to prepare a 125 mg/5 mL suspension? a. 10 mL
b. 1.0 mL c. 40 mL d. 4.0 mL
85. How much dilutant needs to be added to a 500 mg vial of Merrem to obtain a concentration of 50 mg/mL? a. 1 mL
b. 5 mL c. 10 mL d. 50 mL e. 100 mL
86. A patient is to receive 1000 mL of solution over 8 hours. If the administration set delivers 20 gtt/mL, at how many gtt/min should the solution be infused?
a. 4 gtt/min b. 20 gtt/min c. 40 gtt/min d. 0.4 gtt/min
87. A solution is to be administered by IV infusion at a rate of 100 mL/hr. How many gtt/min should be infused if the administration set delivers 20 drops/mL?
a. 5 gtt/min b. 50 gtt/min c. 3.3 gtt/min d. 33 gtt/min
88. A patient is to receive 1 L of a normal saline by IV infusion over 12 hours. What is the rate of infusion expressed as gtt/min if the infusion set delivers 20 gtt/mL?
a. 28 gtt/min b. 2.8 or 3 gtt/min
c. 28 gtt/hr d. 280 gtt/hr
89. An IV infusion for a 22-lb child calls for 4 mcg/kg/min at a rate of 1.2 mL/hr. How many milligrams of a drug are required in a 100-mL infusion solution to supply the required dose?
a. 440 mg b. 200 mg c. 3.3 mg d. 20 mg
90. If 100 g dextrose is dissolved in 100-mL water to make a final volume of 150 mL, what is the %w/v of this solution?
a. 50% w/v b. 66.7%w/v c. 5% w/v d. 6.67% w/v
91. What is the %w/v concentration of a 100 mL of amoxicillin oral suspension containing 150 mg/5 mL? a. 30% w/v
b. 1.5% w/v c. 3% w/v d. 15% w/v
92. If a patient has a temperature of 37C, what is the patient’s temperature in Fahrenheit?
a. 69F b. 100F c. 98F d. 98.6F
93. If a solution has a ratio strength of 1:10000 w/v, what is the % w/v of the solution?
a. 0.01% w/v b. 1.0% w/v c. 0.1% w/v d. 10% w/v
94. The required dose for a 110-lb patient is 0.5 mg/kg/min. If the concentration of the medication is 1 g/100 mL, what is the infusion rate in mL/hr?
a. 2.5 mL/min b. 25 mL/min c. 150 mL/hr d. 15.0 mL/hr
95. If 2.54 g of a drug is used to make 1000 tablets, roughly how many milligrams will 60 tablets contain? a. 25 mg b. 50 mg c. 100 mg d. 150 mg e. 200 mg
96. What is the %w/w of 1000 mL solution when 200 g dextrose is dissolved in 900 mL of water?
a. 18.2% b. 20%
c. 1.82% d. 2.0%
97. A 16 oz. 10 g/15 mL lactulose bottle contains how many tablespoon-doses?
a. 96 doses b. 3.2 doses c. 320 doses d. 32 doses
98. If the required dose is 1 tsp bid, how long will an 180-mL bottle of clemastine fumerate syrup 0.5 mg/5 mL last?
a. 36 days b. 18 days c. 30 days d. 60 days
99. How many milligrams of prochlorperazine are in a 5 mL injection containing 5 mg/mL?
a. 5 mg b. 1 mg c. 10 mg d. 25 mg
100. The recommended daily adult dose of a medication is 2 mg/kg body weight in 4 divided doses. What is the daily dose for a person weighing 110 lb? a. 100 mg daily
b. 25 mg daily c. 220 mg daily d. 10 mg daily
101. Kefzol is ordered at a dose of 30 mg/kg/day divided three times daily for an elderly female patient who weighs 88 lbs. How much Kefzol will be given to her daily? a. 400 mg b. 800 mg c. 1200 mg d. 1.5 g e. 1 g
102. How much Kefzol would have to be drawn up from the vial and injected into an IV bag to make one dose of Kefzol for the patient in question 101? The vial you have on hand was compounded to a
concentration of 325 mg/mL. a. 5.45 mL b. 6.25 mL c. 1.65 mL d. 1.23 mL e. 0.68 mL
103. A bag with 250 mL of NS will be infused over 2 hours using a microdrip set (60 gtt/mL). What is the flow rate in drops per minute?
a. 60 gtt/min b. 100 gtt/min c. 115 gtt/min d. 125 gtt/min e. 140 gtt/min
104. An IV bag with 1250 mL of IV fluids is to be infused over 3 hours with a 15 gtt/mL set. How many milliliters will be infused over each hour? a. 300 mL/hr
b. 345 mL/hr c. 416 mL/hr d. 427 mL/hr e. 458 mL/hr
105. A 240 lb male patient is prescribed zidovudine at a dose of 2 mg/kg three times daily. How much zidovudine will this patient receive daily? a. 218 mg
b. 436 mg c. 654 mg d. 245 mg e. 186 mg
106. A patient weighing 155 lbs is ordered dobutamine at a rate of 5 mcg/kg/min. When the drug is admixed, 200 mg of dobutamine was put into a 500 mL bag of normal saline (NS). What is the final concentration of the solution in mcg/mL? a. 5 mcg/mL b. 40 mcg/mL c. 200 mcg/mL d. 400 mcg/mL e. 444 mcg/mL
107. The required dose of Drug X for a 150-lb patient is 1 mg/kg/min. If the concentration of the medication is 5 g/100 mL, what is the infusion rate in mL/hr? a. 2.1 mL/min
b. 5 mL/min c. 82 mL/hr d. 400 mL/hr
108. What is the milliosmolarity of normal saline (0.9% NaCl) solution? Na¼23, Cl¼35.5 a. 145 mOsm/L b. 220 mOsm/L c. 255 mOsm/L d. 285 mOsm/L e. 308 mOsm/L
109. If a solution contains 1 g of sodium chloride dissolved in 100 mL of D5W, how many milliosmoles are present? (Na¼ 23; Cl ¼ 35.5; hydrous dextrose ¼ 198) a. 60
b. 120 c. 240 d. 300 e. 360
110. An order is received in the pharmacy for an irrigation solution of 0.25% w/v acetic acid. The acetic acid in stock is 99.9% w/w, and must be added to 128 oz of purified water. How many grams of 99.9% w/w acetic acid must be added to the purified water in order to prepare the final irrigation solution?
a. 6.7 b. 8.2
c. 9.6 d. 10.8 e. 12.3
111. One gram of a given chemical is soluble in 10 mL of alcohol. What is the specific gravity of alcohol if a saturated solution is made with this chemical into an 11.1% w/w solution? a. 0.75 b. 0.8 c. 0.9 d. 1.0 e. 1.15
112. How many grams of iodine are consumed daily from 0.3 mL tid of 5% w/v strong iodine solution? a. 450 b. 45 c. 4.5 d. 0.045 e. 0.0045
113. A technician is preparing a potassium chloride infusion for a hypokalemic patient. The IV bag contains 250 mL of normal saline and 5.86 g of KCl (KCl molecular weight¼ 74.6). In the final infusion preparation, how many milliequivalents of
potassium chloride are present? a. 12.7 mEq
b. 78.5 mEq c. 43.7 mEq d. 22.5 mEq e. 36.4 mEq
114. What is the volume of distribution of a drug with a clearance of 9 L/hr, F¼ 50, and an elimination half life of 7.8 hours?
a. 70 L b. 93 L c. 101 L d. 149 L
115. How many mL of tetracycline suspension 250 mg/ 5 mL must be given in order for the patient to receive 150 mg? a. 3 mL b. 6 mL c. 12 mL d. 7.5 mL e. 15 mL
116. An acidic drug has a pKa of 5.4. What percentage of the drug is ionized in urine with a pH of 6.0? a. 25.1%
b. 74.9% c. 20.1% d. 79.9%
117. A weakly basic drug has a pKa of 8.6. What percent would be un-ionized in circulation?
a. 0.059% b. 0.941%
c. 5.9% d. 94.1%
118. A patient is to receive 2 mg/min of labetalol hydrochloride that has been prepared by adding 200 mg of labetalol hydrochloride injection to 250 mL of D5W to attain a final concentration of 2 mg/3 mL. How many milliliters per hour should the nurse infuse?
a. 2.5 mL/h b. 150 mL/h c. 3 mL/h d. 180 mL/h
119. A patient is to receive 4 L of D5NS over 24 hours. If the IV tubing has a drip factor of 15 gtt/mL, what is the drip rate?
a. 18 gtt/min b. 42 gtt/min c. 55 gtt/min d. 250 gtt/min
120. What is the day supply for this prescription? Persantine 25 mg (quantity 100) SIG: 1 tab qod a. 200
b. 100 c. 50 d. 25 e. 20
121. Which erythromycin salt(s) is/are available by IV infusion?
I. Erythromycin lactobionate II. Erythromycin stearate III. Erythromycin ethylsuccinate
a. I only b. II only c. I and II d. I and III e. II and III
122. The hydrogen ion concentration of a topical solution is 1 108. What is the pH of this solution?
a. 8 b. 4 c. 2 d. 6
e. None of the above
123. A 3-mEq/mL solution of KCl contains how many milligrams per milliliter? (MW of KCl¼ 74.5) a. 0.04 mg/mL
b. 24.8 mg/mL c. 111.8 mg/mL d. 223.5 mg/mL
124. A patient is prescribed 10 mEq KCl once daily to compensate for the potassium wasting effects of furosemide. How many mg of KCl is in each dose? (MW of KCl¼ 74.5)
a. 3.73 mg b. 7.45 mg
c. 372.5 mg d. 745 mg
125. CH is a 72-year-old woman who requires empiric vancomycin treatment for pneumonia. She is 50 200and weighs 125 lbs. Her SCr is 1.2 mg/dL. What is her calculated creatinine clearance?
a. 33.5 mL/min b. 39.4 mL/min c. 38.0 mL/min d. 44.7 mL/min
126. JW is a 64-year-old man with a prior medical history positive for hypertension and poorly controlled diabetes. He presents to the ED today complaining of fever and chills that have progressively worsened over the last 24 hours. His physical exam is
unremarkable with the exception of an oozing foot ulcer. The medical team wants to begin empiric antibiotic treatment including an aminoglycoside. What is his calculated creatinine clearance? (height ¼ 50800, weight¼ 247 lbs, SCr ¼ 1.1 mg/dL)
a. 61.3 mL/min b. 55.8 mL/min c. 65.6 mL/min d. 107.8 mL/min
127. A patient’s labs show serum calcium of 8.7 mg/dL and serum albumin of 3.2 g/dL. What is her corrected calcium concentration?
a. 8.7 mg/dL b. 9.34 mg/dL c. 8.06 mg/dL d. 14.46 mg/dL
128. How many milliliters of water should be added to 100 mL of a 1:125 (w/v) solution to obtain a solution such that 25 mL diluted to 100 mL will yield a 1:4000 strength solution? a. 300 mL b. 400 mL c. 500 mL d. 600 mL e. 700 mL
129. Using the following WBC and differential, calculate this patient’s absolute neutrophil count (ANC). WBC: 2.0 103/mm3 Segs: 14.8% Bands: 5% Lymphocytes: 55% Monocytes: 22% Eosinophils: 1.7% Basophils: 1% a. 99/mm3 b. 196/mm3 c. 396/mm3 d. 540/mm3
130. What is the pH of a buffer solution containing 0.25 M of acetic acid and 0.75 M of sodium acetate? (Ka¼ 1.75 10-5)
a. 3.87 b. 4.28 c. 5.24 d. 6.53
131. A drug is available as both a 150-mg tablet and 100 mg capsule. The AUC for the tablet was calculated to be 76.3 mg.hr/L and for the capsule 84.2 mg.hr/L. What is the relative bioavailability of the tablet with respect to the capsule?
a. 0.61 b. 0.73 c. 0.91 d. 1.37
132. If a person is 138 pounds and 66 inches, what is their BMI (Body mass index) (kg/m2)?
a. 46 b. 22.2 c. 2.2 d. 703 e. 12.5
133. TJ is a 23-year-old woman who has a long history of poorly controlled asthma. She is admitted to the hospital with a severe asthma attack is is started on aminophylline. She is currently receiving a
continuous infusion of aminophylline at 40 mg/hour. The patient has not experienced any adverse effects and is responding well to therapy. Her steady-state theophylline concentration is 12.6 mg/mL. What dose of oral theophylline sustained-release formulation may she be converted to? a. 600 mg q12h
b. 400 mg q12h c. 200 mg q12h d. 800 mg q12h e. None of the above
134. What statement is true regarding first order kinetics?
I. Drug is metabolized at a rate that is constant overtime.
II. Aspirin is metabolized through first order kinetics. III. V¼ Vmax [C]/km a. I only b. III only c. I and II d. II and III e. I, II and III
.... ... .... ... ... .... ... .... ... .... ... .... ... .
Compounding
CHAPTER
3
...The Federal Drug Administration (FDA) defines traditional pharmacy compounding as “the combining, mixing, or altering of ingredients to create a customized medication for an individual patient in response to a licensed practitioner’s prescription (www.fda.gov). Compounding is often used when the patient is intolerant of a
manufactured drug. It may also be needed when an alternative route of administration is needed and not available commercially. It also allows physicians to prescribe customized strengths and dosage systems. I. Regulation
The FDA established current Good Manufacturing Practices (cGMP) to ensure that minimum standards are met for drug product quality. The National Association of Boards of Pharmacy (NABP) formulated “Good
Compounding Practices” that are used by many states. These can be found in the United States Pharmacopeia-National Formulary (USP-NF) and establish standards for extemporaneous compounding of nonsterile and sterile preparations.
II. Quality assurance
A. Nonsterile products1: The following questions are to be considered carefully before compounding: 1. Have the physical and chemical properties and
medicinal, dietary, and pharmaceutical uses of the drug substances been reviewed?
2. The first time a product was compounded, was documentation made of the materials and equipment used, method of mixing, labeling requirements, and dating determination? 3. Are the quantity and quality of each active
ingredient identifiable?
4. Will the active ingredients be effectively absorbed, locally or systemically according to the prescribed purpose, from the preparation and route of administration?
5. Are there added substances, confirmed or potentially present from manufactured products, that may be expected to cause an allergic reaction, irritation, toxicity, or undesirable organoleptic response from the patient? Are there added substances, confirmed or potentially present, that may be unfavorable (e.g., unsuitable pH or inadequate solubility)? 6. Were all calculations and measurements
confirmed to ensure that the preparation will be compounded accurately?
7. Were expiration dates of all compounding materials being used checked?
8. Are there clear labeling and directions?
9. Are there instructions regarding proper handling and storage of the medication? 10. Does it look or smell like it should? B. Sterile products
1. Check compatibilities between drug-vehicle, drug-drug, and drug-container.
2. The finished product should be free of contamination, such as particles, bacteria, pyrogens.
3. All compounding materials should be checked for expiration date and proper function before use.
4. The solution should be clear, with all drugs completely in dissolution.
5. Final products should have seals or appropriate closures to indicate that the product has not been contaminated or manipulated since it was compounded and that it was checked and verified by the pharmacist so that nothing is added to the final product.
6. Clear labeling and directions should be present. 7. Labeling and instructions for proper
handling and storage of medication should be present.
8. Logs/documentation/lot numbers should be present.
III. Requirements for Compounding A. Materials
B. Equipment 1. Beaker
2. Biologic safety cabinet 3. Flask 4. Mortar 5. Ointment slab 6. Pestle 7. Scale 8. Stirring rod 9. Syringe/needle
10. Weighing paper/weighing boat 11. Spatula
C. Compounding area
1. The product may be flammable (e.g., alcohol), highly reactive (e.g., phenol), or cytotoxic (e.g., chemotherapy). The pharmacist may need to prepare the medication in a vertical flow hood to prevent harm to himself/herself. The pharmacist should use appropriate attire (e.g., gloves, gowns, facial covering).
IV. Achieving Stabilization of the Preparation A. Temperature
