Two words that send most nursing students anxiety through the roof: Dose Calc. (I know that I just went tachycardic).
Most nursing programs require you to take at least one dosage calculation exam to continue in their program, and a lot of schools require multiple exams…YIKES!
But in all seriousness, this is a super duper big deal.
Not only because you need to pass these tests to become an RN, but because you will be giving medications on a daily basis and need to calculate them correctly to avoid hurting your patients. *Gulp.*
I know you’ve felt the immense stress and pressure of calculating medication dosages, but luckily I’ve done the hard work for you!
I have put together 6 steps that will ensure you always get the right answer, both on the exam and in real life.
Make sure that you follow the steps in order, as skipping steps might cause you to miss the right answer.
Download your FREE Dose Calc Conversions Cheat Sheet that you can take with you to clinical!
Dosage Calculation Steps
Figure out what you need.
What is the question asking you for?
Do you need mL, mg, g, number of tablets or gtts/min? Often times you’ll see a question that looks easy on the surface, but is actually asking you something different than you originally thought.
Your patient, Mary, has been hospitalized for 4 days for bacterial pneumonia. She is prescribed 250mg of levofloxacin to be taken orally once per day for the next 14 days until her next appointment. You are getting ready to pass her morning meds but you only have 500mg tablets in your med cart. Mary is going to be discharged this afternoon. How many milligrams total will Mary need to go home with?
At first glance, this question looks like you need to figure out how many tablets Mary will be receiving. But it is actually asking you how many milligrams Mary will need to go home with. You need to read the entire questions before you decide what the question is really asking.
Write what you need at the very right hand side of your paper.
Figure out what your order is.
What does the order or prescription say?
In the example, the only information we need is her prescribed dose (250mg), how often she takes it (once per day), and how long she will be taking it (14 days).
We do not need to pay attention to the other details, such as how long she’s been in the hospital and how many milligrams the tablets are in the med cart.
Write what your order is at the very left hand side of your paper.
Figure out what conversions you need.
What medication, unit, or product does the question make available to you? Are you needing to convert grams to milligrams? Minutes to hours? Or milliliters to drops?
Pick out the information that pertains to the answer you need, and cross out unnecessary details. If the test is on paper, I like to physically cross out information I do not need to keep me from getting distracted.
In this case, we are keeping the dosage unit in milligrams, but we need to figure out how many milligrams she needs for 14 days.
Write all of the conversions you need to do in the middle of the paper.
Solve the problem.
Multiple across the top line. Multiply across the bottom line. And divide both of those numbers. This is a super awesome fraction trick that does the conversions for you, and one of the top reasons why I love the dimensional analysis method so much.
Write the answer appropriately. A handy dandy mnemonic to remember this is: Nurses are LEADERS, not FOLLOWERS.
This means that you include leading zeros, but never trailing zeros.
Let’s say your calculator said something like .5. We wouldn’t write this answer as just .5 because imagine how easy it would be for that decimal point to get lost and the dose to turn into 5.
And we definitely wouldn’t write it as .50 for the same reason. 50! Oh my!
So, friend, no trailing zeros! You need to watch them at all times, so keep them in front! 🙂
The only correct way to write it is 0.5. Even if the decimal gets lost, it will look like 05, causing others to double check where the decimal is.
For our above example, the answer is 3500mg. We would not write it as 3500.00mg, 3,500mg, or 03500mg. Simply write it as 3500mg.
Check your work.
Checking my work has saved by booty more than once on exams and in the real world.
Seriously, friend, save yourself the stress and anxiety that comes with questioning yourself or hurting your patient just because you didn’t take the extra few seconds to check your calculations.
Take a step back, breathe, and do the problem again. The patient’s apple juice can wait. Safe nursing practice is always your number one priority.
Dosage calculations can be intense, and you should always be very careful when doing the math. Thankfully, these steps will help take some of the pressure off.
Download your FREE Dosage Calculation Conversions Cheat Sheet to take with you to clinical so you can reference it anytime you need!
Comment below and tell me the biggest thing you struggle with in dosage calculations.