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'How can I be a nurse one day if I can't do drug calculations?'


Jenny talks to us about struggling with drug calculations in practice

It would be naïve to expect to never have to do drug calculations as a student nurse, however as soon as I see the numbers jumbled up on a page in a mock exam, I suddenly feel as though the world is being asked of me.

The difference between my drug calculation entrance exam for university and being out in clinical practice of course is the fact that in reality you don’t have the luxury of multiple choice answers.

In practice, drug calculations are not something that you can ‘kind of know’ or ‘think that it’s right’ and multiple choice exam questions may lure student nurses into a false sense of security. Seeing four lovely little answers in front of you is much more satisfying as you can get away with not really knowing but making an educated guess … guesstimating if you will.

I was once quizzed by a mentor on a medication round who was about to administer an injection. She asked me what amount of drug she should be drawing up. The spotlight was on me, even the patient looked as if they were judging me, as I tried to formulate an answer that I knew I would never get if I thought about it all night. Of course I started with some ‘uhmms’ and ‘ahhs’ before admitting defeat, but felt very embarrassed that I could not provide her with an answer. The patient looked relieved that I wasn’t going to be administering the injection.

How could I be a nurse one day if I couldn’t do drug calculations?

Luckily my mentor was lovely and put me at ease immediately. She joked that she only asked me because she didn’t know herself (although I’m sure she was just being kind…) Her colleague came over and they calculated the dosage together, explaining fully to me how they formulated their answer which I found extremely useful.

In fact the way in which they taught me in practice seemed much easier to digest than trying to adopt the official mathematical formula that we have been taught at university.  

Drug calculations are daunting for a student nurse, but I think the key is to step back, take a deep breath and…think!  

And if you don’t know the answer, then you don’t know it, simple as that.

There is no harm in admitting it and asking for help, and in fact seeing qualified nurses asking for help with their drug calculations is not uncommon or a big deal!

But if you are able to participate in medication rounds with your mentor then take that as a golden opportunity to practice, practice, practice! Hopefully one day somebody will come to me and ask me for help with their dosages, and perhaps I’ll be able to quiz my students with drug calculations …

Jenny Wilcock is a second year adult nursing student at the University of Leeds.


Readers' comments (4)

  • Adam Roxby

    Hi Jenny

    Really like the article. I wrote about my experience with drug calculations here ( but it;s great to see if form a different perspective.

    Keep practicing and I'm sure you will be fine.

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  • George Kuchanny

    "even the patient looked as if they were judging me" - you can bet your months salary the patient is! Unless s/he does not care about being killed accidentally that is :)

    The best thing here is that you acknowledge and fully understand the limitation. Unfortunately some just 'wing it'. Not good at all believe me. (I never know how to spell believe, lost without a spell checker I am afraid to say).

    As you say, multiple choice is not a brilliant way to set an exam in any event. Poring over each calculation very carefully and asking a clever person to explain each wierd bit in detail may be the way forward. May the force be with you. Never be tempted to wing it and do an Urbani!

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  • Sha12

    Thanks so much for writing about this, I'm dreading the calculations I'm not a wizard at Maths. But like you said practice practice practice.

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  • Hi does anyone know of a book to help practice calculations ie the formulas

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