Dosage calculation

Nurse.Kelsey, BSN, RN · Sep 17, 2019

Hi, sorry to hear that you have a school giving you by-hand calculation math tests. Although its a skill that is good to have, realistically times have changed...we dont HAVE to do any dosage calculations by hand in the real world...

Anyways my advice to you is to really really practice. Sometimes its nerves. You can settle your nerves by practicing a lot. Use a dosage calculation workbook, kaplan has a nice one.

Professor X, MSN, RN · Sep 17, 2019

I'm sorry, Nurse Kelsey, but you are incorrect. In my in-patient positions, I have found numerous errors in pre-printed "cheat sheets" and pharmacy dosing because people thought they did not need to do math. Being able to calculate accurately is essential for IV titration, injectable medications, as well as oral medications. Nurses are the last line before incorrect doses are given, and they need to be accurate. Doses may come pre-measured, but nurses need to recognize when they are incorrectly calculated. This is the real world.

OP, I suggest you ask for a written policy on the rounding rules so you are providing the correct answer. You may be doing the math right, but 1.66 is not the same answer at 1.7, and .9 is definitely not the same thing as 0.9. The way you "express" your answer may be incorrect, rather than your calculations. And by all means see a tutor if one is available. If you are doing math by any method other than dimensional analysis (ratio/proportion, "doc over stock" or "in your head") please stop. Watch a youtube about dimensional analysis if you do not remember enough from chemistry.

I am a professor of nursing and I spend many office hours giving individual instruction on dimensional analysis to fix whatever ridiculous method of math my students were taught. 10 minutes of instruction in this method, and anyone can pass.

One more thing...remember, they call it "dosage calculation" or even "med math" but its NOT! It's just MATH! The same math that has been around since Euclid fiddled around with math in the 4th century! Just numbers! We see numbers every day...they aren't scary. Don't let the terminology stress you out! And look at your numbers before you turn in the test to see if they "make sense" in a general way (were you adding two liquid amounts and came up with a smaller answer? probably not the right answer).

Best of luck. Repost and tell us how you did.

Wuzzie · Sep 17, 2019

4 hours ago, Nurse.Kelsey said:
Hi, sorry to hear that you have a school giving you by-hand calculation math tests. Although its a skill that is good to have, realistically times have changed...we dont HAVE to do any dosage calculations by hand in the real world...

Oh yes you do and thinking that you don't is going to set you up for errors!!

To the OP, what Letters After My Name said is true. It's just math, easy math and I suck at math. My guess is you are getting confused by the "distractors" most calculation questions have in them. We can help you. Post a question that you got wrong and show us what you did. We can correct your errors in a way that will help you going forward. We've done it many, many times.

thepersistentone28 · Sep 17, 2019

1 hour ago, Wuzzie said:
Oh yes you do and thinking that you don't is going to set you up for errors!!
To the OP, what Letters After My Name said is true. It's just math, easy math and I suck at math. My guess is you are getting confused by the "distractors" most calculation questions have in them. We can help you. Post a question that you got wrong and show us what you did. We can correct your errors in a way that will help you going forward. We've done it many, many times.

I can remember the exact question but it was like 5 mg and you have 20 mg round to the nearest hundredth. Which was 0.25 So me not realizing I put 0.3 and when I got home I realized it would have been 0.25 because their is nothing after the 5. Apparently I did that a lot because my score would have been better if I had realized it. I had studied rounding but never did it with only three numbers , of course it threw me off I just can’t believe it I worked so hard. But then again math has always been my weakness :(. Just feeling down in the dumps.

Wuzzie · Sep 17, 2019

5 minutes ago, thepersistentone28 said:
I can remember the exact question but it was like 5 mg and you have 20 mg round to the nearest hundredth. Which was 0.25 So me not realizing I put 0.3 and when I got home I realized it would have been 0.25 because their is nothing after the 5. Apparently I did that a lot because my score would have been better if I had realized it. I had studied rounding but never did it with only three numbers , of course it threw me off I just can’t believe it I worked so hard. But then again math has always been my weakness :(. Just feeling down in the dumps.

Yeah, you got yourself freaked out and rounded to the tenth instead of the hundredth. It happens. So is that the only thing you were doing wrong (rounding off) or did you have difficulty coming up with the correct answers as well?

thepersistentone28 · Sep 17, 2019

24 minutes ago, Wuzzie said:
Yeah, you got yourself freaked out and rounded to the tenth instead of the hundredth. It happens. So is that the only thing you were doing wrong (rounding off) or did you have difficulty coming up with the correct answers as well?

Nope it was just the rounding and I had a tutor I went to last week spent 4 hours I had it then when the test came bam must have forgotten how to do it ??‍♀️

Nurse3721y, BSN · Sep 17, 2019

As a math tutor I found that the best way to learn this type of stuff is to go back to basics. Write every conversion out with the units on the math problem so that you can actually think through the problem. Maybe get a book like dosage calculations made easy

car48 · Sep 17, 2019

I always double check the meds before I give them because in RL the math is not all that hard. 99% of the time in my experience most medication adjustments are nothing more than braking a pill in 1/2. But you have to know the math, because you have to know the math. It is what it is.

I am actually really good at math, but I did not get one math question on NCLEX. That annoyed me, but in reality it makes sense because math is not even 1% of our job.

thepersistentone28 · Sep 18, 2019

4 hours ago, Nurse3721y said:
As a math tutor I found that the best way to learn this type of stuff is to go back to basics. Write every conversion out with the units on the math problem so that you can actually think through the problem. Maybe get a book like dosage calculations made easy

Just bought a book on amazon today workbook to refresh! Hopefully help me so I don’t make these mistakes again!

frozenmedic · Sep 21, 2019

On 9/17/2019 at 11:33 AM, Letters After My Name said:
If you are doing math by any method other than dimensional analysis (ratio/proportion, "doc over stock" or "in your head") please stop. Watch a youtube about dimensional analysis if you do not remember enough from chemistry.
I am a professor of nursing and I spend many office hours giving individual instruction on dimensional analysis to fix whatever ridiculous method of math my students were taught. 10 minutes of instruction in this method, and anyone can pass.

You exist?!?!?!? I have also spent hours successfully teaching students dimensional analysis and cannot understand why it is not the educational standard. The other formulas to memorize are indeed ridiculous, error prone, and non-transferable to other situations.

Read the "Letters After My Name" post and do exactly as he/she says!