Drug Calculation Questions
R Sinclair, Pharmacy 18.8.2005
Drug calculation questions are a major concern for most pre-registration pharmacists and are also a worry for those involved in pre-registration training. When it is obvious that people are struggling with what are basic calculations, as part of a test exam or at their workdesk, one would be right to question their ability to accurately calculate doses in critical situations or environments such as on the Ward.
This Booklet is not designed to train you in undertaking Pharmaceutical calculations per se but to assist with calculation questions
Drug Calculations 2
Compiled by R Sinclair 2012
This Booklet is designed to accompany Booklet 1 and is structured to contain at the start some examples of calculations that students have stated they find difficult followed by a step by step approach to solving the problem
- Source: resourcepharm.com (kindly provided to us by Roy Sinclair, the author of these booklets)
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Calculating doses
These short presentations take you through the steps in how to calculate the doses you need to give a patient.
- Calculating tablets
- Calculating mixtures & solutions
- Calculating IV rates: mls per hour (& minute)
- Calculating IV rates: drops per minute (dpm)
- Calculating IV rates: time remaining
- Source: flinders.edu.au
- Pharmacy Resource: Presentations
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Drug Calculation Exam Practice Child
Drug Calculation Exam Practice (Child) – Set A
Drug Calculation Exam Practice (Child) – Set B
Drug Calculation Exam Practice (Child) – Set C
Drug Calculation Exam Practice (Child) – Set D
Drug Calculation Exam Practice (Child) – Set E
Drug Calculation Exam Practice (Child) – Answers for Set A – Set E
- Source: unihub.mdx.ac.uk
- Pharmacy Resource: Questions and Answers
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Drug Dosage Calculations
This handout covers a variety of numeracy based tasks which nurses and midwives may be required to perform in practice. These include drug calculations and setting drip rates on the controls of intravenous infusion controllers.
The handout covers the following: SI units and conversions, calculating drug quantities in both tablet and liquid form, and calculating intravenous flow rates and drip rates. Exercises are included at the end of each lesson. Answers are on the back page.
- Source: nottingham.ac.uk
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Objectives
- Be able to work out a drug calculation
- Understand the importance of getting
calculations right - How to convert units and measures safely
- Be able to access and use appropriate
resources when carrying out a drug calculation
- Source: covwarkpt.nhs.uk
- Pharmacy Resource: Presentation
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Pharmacy Calculations
At a Glance / Pharmacy Calculations
- Amount Strengths
- C1V1=C2V2
- Concentrated Waters
- Converting Strengths
- Diluting a Percentage Solution
- Formulations
- Half-lives
- Increasing a Percentage Solution
- Mixing Concentrations
- Multiple Dilutions
- Percentage Strengths
- Prescriptions (1)
- Prescriptions (2)
- Prevalence
- Ratio Strengths
- Serial Dilutions
- Units & Strengths
- Source: kent.ac.uk
- Pharmacy Resource: Guides
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Dispensary-based calculations for pharmacy technicians
This e-learning from CPPE has been developed to support pharmacy technicians with dispensary-based calculations to ensure accuracy and safety when preparing, dispensing and checking prescriptions for patients.
- Source: cppe.ac.uk
- Pharmacy Resource: CE / CPD / Learning
- Register to Access Content: Yes
Clinical calculations for pharmacy professionals
The aim of this programme is to support pharmacy professionals with calculations in clinical settings when preparing, prescribing or checking medicines or when advising other healthcare professionals. The principles can be applied to any sector of pharmacy practice.
- Source: cppe.ac.uk
- Pharmacy Resource: CE / CPD / Learning
- Register to Access Content: Yes
- Source: southteeslri.co.uk
- Pharmacy Resource: Workbook
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Study Guide with Sample Questions
- Source: nr.edu
- Pharmacy Resource: Guide
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Numeracy Help for Healthcare Professionals
This HSK Academic Skills Advice website resource includes video tutorials and interactive exercises
- Flow rate calculation for a volumetric pump
- IV drip rate calculation
- Tablet dosage calculation
- Volume conversion
- Volume required calculation
- Weight conversion
- Weight-based dosage calculation
- Source: academic-skills.health.herts.ac.uk
- Pharmacy Resource: Videos & Exercises
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Nursing calculations
The following videos are an introduction to basic drug calculations for nursing.
In this tutorial
- Finding the volume required
- Using proportions with liquid solutions
- Converting between large and small units
- Medication dosage by body weight
- Managing fractions and decimals
- Drop factor: converting between millilitres and drops
- Converting flow rates between mL/hr and dpm
- Source: rmit.edu.au
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Nursing Medication Calculation Formulae
Formula sheet for nursing students including dosage, drop and infusion rates, unit conversion and BMI calculations contributed to the mathcentre Community Project by Shazia Ahmed, University of Glasgow. The leaflet is designed to be printed double-sided on A4 paper and folded into quarters lengthwise first.
- Source: mathcentre.ac.uk
- Pharmacy Resource: Leaflet
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Dilution of solutions for nurses
This leaflet explains how dilution calculations are performed.
- Source: mathcentre.ac.uk
- Pharmacy Resource: Leaflet
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Pharmacy calculation I: Solid trituration
A leaflet explaining how solid trituration calculations are performed for the dilution of drug powders. The resource is contributed to the mathcentre Community Project by Abigail Francis and reviewed by Bob Morris, Liverpool John Moores University
- Source: mathcentre.ac.uk
- Pharmacy Resource: Leaflet
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Pharmacy calculations II: Isotonicity
A leaflet showing how to calculate the freezing point depression of a solution. The resource is contributed to the mathcentre Community Project by Abigail Francis and reviewed by Bob Morris, Liverpool John Moores University
- Source: mathcentre.ac.uk
- Pharmacy Resource: Leaflet
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Maths for Healthcare Professionals
Contents
Fractions
Decimals
Ratio
Percentages
BMI
Averages
Unit Conversion
Dosage Calculations
- Source: hull.ac.uk
- Pharmacy Resource: Guide
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Numeracy – The Essentials
The following guide will provide an overview of the basic numeracy skills required for first year Nursing students.
Contents
- Place Value
- Times Tables
- Addition
- Multiplication
- Subtraction
- Division
- Combined Functions
- Converting Weights
- Fractions & Decimals
- Basic Drug Calculations
- Percentages
- Source: qub.ac.uk
- Pharmacy Resource: Guide
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MEP Help Modules
These modules cover the 10 topics listed.
- Algebra
- Decimals
- Equations
- Fractions
- Geometry
- Handling Data
- Mensuration
- Numbers
- Percentages
- Probability
- Source: cimt.org.uk
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Misconceptions
There are many misconceptions in people’s understanding of mathematics which ultimately give rise to errors. The authors have identified 24 of those most commonly found and of these, the first 8 are listed below.
- Rounding Numbers
- Multiplication can Increase or Decrease a Number
- Multiplying Decimals
- Decimals and their Equivalent Fractions
- Dividing Whole Numbers by Fractions
- Adding with Negative Numbers
- Calculations with Negative Numbers
- Calculations with Hundreds and Thousands
- Source: cimt.org.uk
- Pharmacy Resource: Questions and Answers
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Session 1: Review of Arithmetic for Drug Calculation
The process of drug calculations involves arithmetic which deals with the study of numbers. This session will cover:
- A review of mathematical terms
- Multiplication and division by 10, 100 and 1000
- Multiplication of decimals
- Conversion of units
- Source: tees.ac.uk
- Pharmacy Resource: Workbook and Answers
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Session 2: Review of Arithmetic of Fractions used in Drug Calculations
The arithmetic of fractions is very important groundwork which must be known before calculation of quantity of drugs given to patients.
- Source: tees.ac.uk
- Pharmacy Resource: Workbook and Answers
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Session 3: Application of fractions in calculations of dosages of tablets, syrups and suspensions
Drugs are administered via several routes, including by injections, by intravenous infusion or orally. Oral medication is the first medication that a student nurse will learn to calculate for patients.
- Source: tees.ac.uk
- Pharmacy Resource: Workbook and Answers
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Medications Calculations Practice
Medications calculations practice and answers
- Source: sls.navitas-professional.edu.au
- Pharmacy Resource: Questions and Answers
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The following examples explain the formula and the ratio method of medication calculation.
- Source: usq.edu.au
- Pharmacy Resource: Tips
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Intravenous Infusion Calculations
Drip Rates — is when the infusion volume is calculated into drops.
- Source: usq.edu.au
- Pharmacy Resource: Tips
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Session 4: Calculation of Drip and flow rates (infusion rates)
Skills covered in this section include: calculating the volume of fluid delivered to a patient over a given time, rates of flow in ml/hour and rates of flow in drops/minute.
- Source: tees.ac.uk
- Pharmacy Resource: Workbook and Answers
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Drug Calculations 1- Converting units
Converting metric units for nurses and nurses in training
- Source: youtube.com
- Pharmacy Resource: Video
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Numeracy Skills for Drug Calculations
Drug Calculations are only a small part of nursing but nevertheless important. These e-learning resources should equip you with essential numeracy skills and help you with exam preparation. The materials have been split into sections so begin by choosing your year and intake and work through the topics you require.
Basic Drug Calculations
Conversions
Drip Rates
Fluid Balance Charts
Labels
mLs per hour
Percentages
Tablets
Intermediate Drug Calculations
Conversions
Drip Rates
Labels
mLs per hour
Percentages
Tablets
Maintenance Fluids
Difficult Drug Calculations
Intermediate Drug Calculations
Conversions
Drip Rates
Labels
mLs per hour
Percentages
Tablets
Time
Intermediate Drug Calculations
Conversions
Drip Rates
mLs per hour
Percentages
Time
Maintenance Fluids
Difficult Drug Calculations
Intermediate Drug Calculations
Conversions
Drip Rates
mLs per hour
Percentages
Time
- Source: qub.ac.uk
- Pharmacy Resource: e-Learning
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A Numeracy Refresher
Many students worry about anything to do with numbers, having done little since their GCSEs. This booklet has been designed to offer practice and explanation in basic processes
Contents
- Decimals
- Fractions
- Approximations
- Averages
- Percentages
- Ratios
- Answers
- Source: mathcentre.ac.uk
- Pharmacy Resource: Booklet
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Videos
Calculating Volumes for Injection
Non Calculator Methods for Nursing Students
Understanding Numeracy Questions for Nurses
- Source: unihub.mdx.ac.uk
- Pharmacy Resource: Videos
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Nursing Calculations Workbook
Metric Conversions
Giving the Correct Amount of Tablets
Giving the Correct Amount for Injection
Body Weight Calculations (single dose)
Body weight calculations (TDD and divided doses)
Infusion Rate Calculations (ml/hour)
Infusion Rate Calculations (drops/minute)
Calculating Infusion Times
Calculating Infusion Volumes
Working with Percentage Strength
- Source: unihub.mdx.ac.uk
- Pharmacy Resource: Workbook
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Medication Calculation Practice Problems
- Source: cookchildrens.org
- Pharmacy Resource: Questions and Answers
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Drug Calculations
Read the following information carefully before attempting the examples and exercises.
- Source: pearson.com.au
- Pharmacy Resource: Examples and Exercises
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Maths and Clinical Calculations Workbook
Section 1: Decimals, Fractions & Percentages
Section 2: The SI Units – Weight & Volume
Section 3: Drug Doses & Clinical Calculations
Section 4: Body Mass Index
- Source: scionpublishing.com
- Pharmacy Resource: Workbook
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Drug Calculation Exam Practice Adult
Drug Calculation Exam Practice (Adult) – Set 1
Drug Calculation Exam Practice (Adult) – Set 2
Drug Calculation Exam Practice (Adult) – Set 3
Drug Calculation Exam Practice (Adult) – Set 4
Drug Calculation Exam Practice (Adult) – Set 5
Drug Calculation Exam Practice (Adult) – Answers for Set 1 – Set 5
- Source: unihub.mdx.ac.uk
- Pharmacy Resource: Questions and Answers
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When calculating how much of a drug is required, working with the formula helps the accuracy of the calculation.
- Source: cdhb.health.nz
- Pharmacy Resource: Questions and Answers
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IV Drug Calculations
- Section 1: Units & Equivalences
- Section 2: Calculating dose as volume
- Section 3: Drug Strengths & Stated Concentrations
- Section 4: Duration of Infusion – Stated rate (dose per min) & Infusion rate (mL/hr)
- Section 5: Infusion Rate Calculations
- Source: nhsggc.org.uk
- Pharmacy Resource: Handout
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Intravenous therapy: Drug calculations and medication issues
The remit of this paper is to illustrate the different facets of drug calculations, to explore the occurrence of common medication errors and briefly describe factors that influence the incidence of adverse drug events.
- Source: infantjournal.co.uk
- Pharmacy Resource: Journal Article
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Pharmacy Resources Last Checked: 22/09/2021