Lesson 1: What Happens When the Math is Wrong?

Thought Activity

Please take the time to reflect on these questions.

  • In your own experiences, can you describe an instance where a medication error may have caused an adverse reaction? What local protocols do you perform to reduce this risk? Can you reference an incident where a medication error occurred? What was the outcome? Feel free to cite news sources or other literature.
  • Do you think that such mistakes rarely happen or do they happen all of the time and the public just doesn't hear about it?
  • Who do you think should be held responsible for a mistake such as this?
  • What if this happened in the hospital or doctor's office, who would be responsible?
  • Is there a way for a health care provider to avoid making such a mistake?

Avoiding Mistakes

One way that medical personnel can avoid such mistakes is to calculate dosages using a standardized formula. The formula most commonly used is D/H x Q. We are going to be practicing using D/H x Q to calculate medication dosages from physician's orders.

We will begin by first having a review of basic math. This is so that you can be refreshed on using decimals since dosages are calculated and rounded to the nearest 10th of a number. This makes it easier to prepare medications for administration, particularly liquids that must be poured or drawn up in a syringe since medication cups and syringes are calibrated in 10ths of a cc/ml.

Though we are focusing specifically on the calculation of medication doses today, in other class sessions we will learn about drug classifications, parts of a medication prescription, and routes of administration of drugs.


Creative Commons License Questions from the Forum Activity have been derived and modified from "Dosage Calculations" by Tina Jackson and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Creative Commons License All other material in this work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. If you would like  to use this material, please provide attribution as follows: Richmond, J. (2016). https://www.ceces.ca/courses/med-math/. Continuing Education Centre for Emergency Services.

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