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Arithmetic for Drug Calculations


Drug Calculations Supporttablets

Nurses need to facilitate the safe and accurate administration of medicines.  To do this they need to carry out basic drug calculations.

These materials have been created in order to help students understand the basic maths required in order to carry out those drug calculations. The materials have been designed using one method of calculations, for alternative methods and advice please see the recommended books on this page or discuss with your tutors.

This advice is for a number of different courses. Please check with your module leader as to which guidance is most relevant to you.

Workbook 1: multiplication and conversion

The process of drug calculations involves arithmetic which deals with the study of numbers.  This workbook covers:

  • A review of mathematical terms
  • Multiplication and division by 10, 100 and 1000
  • Multiplication of decimals
  • Conversion of units

Workbook 2: fractions

The arithmetic of fractions is very important groundwork for the calculation of quantity of drugs given to patients.  This workbook covers:

  • Proper and improper fractions
  • Simplification of fractions
  • Multiplication of fractions

Workbook 3: oral medication and injections

This workbook covers how to apply the techniques learned in the previous two workbooks, in order to calculate the amount of doses for injections and syrups.  It includes:

  • Worked examples for oral medication
  • Worked examples for syrups and injections

Workbook 4: infusion rates

Drugs are administered via several routes, including by intravenous infusion.  This workbook covers how to apply the techniques to flow rates, including worked examples for per minute and per hour drip rates by using 3 different formulae.

Useful web links and further reading

Click on the image to see additional useful resources

Reading list

Using Material on this page