Do nurses do med math

[direw0lf]

A pharmacologist teaches our pharmacology class, and I asked her the other day "I know this is important, but I was told that nurses don't actually ever do dosage calculations in the real world nursing, is that true?" and she said yes, the pharm does that for you. I asked what about even checking to make sure an order is correct (because our nursing instructors warned us to always check if an order looks wrong) and she said the pharm always checks that too. But it made me wonder, why are there so many medication errors then? Do nurses do dosage calculations? Thanks.

[dave4151]

Yes you must know med math. If you're having trouble with it, you'll need to sit down with a nursing calculation practice book and practice, practice, practice. You're not only going to be dealing with meds dispensed by a Pyxis or similar. If you're an RN, you have to be able to calculate IV flow rates; 250 mg of K+ infused over 30 minutes is going to have a catastrophically different outcome than infusing the same amount over 24 hours. Also as patient advocates we are the last line of defense against med errors. It's your patients' lives and your license/livelihood at stake. Don't take a nonchalant attitude towards math. I know it's tedious and boring but it's absolutely necessary. As for the instructor who told you that you don't need to know med math, they need to be reported to your department chair.

[Here.I.Stand, BSN, RN]

Cases in point from my practice:

Very unstable admit, direct from helicopter. I had to mix my own levophed, because there was no time to wait for the pharmacy to send it. I think BP was in the 50s/20s at the time.

Pharmacy sent me 20 ml of med in a prefilled syringe. Appropriate dose for that concentration was 10 ml. Barcode scanning only verfies that the label is accurate.

[Here.I.Stand, BSN, RN]

Oh, and like a PP said, peds meds (including code drugs) are often weight based. Inaccurate med math can kill a child.

[Kristenlaurenw]

I work in the ER and although our pumps are programmed with the correct rates based on you putting in the med and dose, we do have patients that need drips mixed and if pharmacy isn't there or if it's emergent, it's nurses who are mixing those drips and titrating them. It's very important that you know how to do med math!

[direw0lf, BSN]

Thanks so much for people's replies sharing why it's needed and examples of when you use med math! I think I was hoping to use "nurses don't do math" as an excuse since I'm having trouble with it, but nope, I'm going to practice until it gets better. Does anyone recommend any study aids for learning this?

[Rose_Queen, BSN, MSN, RN]

Here's a thread to start with: Student Resources: Nursing Math.

[NurseGirl525, ASN, RN]

You wil get it, I promise. Now, the med math questions are the be only ones I can count on for the test!!!

[direw0lf, BSN]

You wil get it, I promise. Now, the med math questions are the be only ones I can count on for the test!!!

Thanks! I decided to just do dosage calculations and no "scenarios" even though I thought "Oh I got this already" I did more. That actually helped when I went back to my book with the problems that added in the patient info and other things! My brain went right to what I'm supposed to pick out of all that. It felt good :)

[NICUmiiki, DNP, NP]

I work in the NICU. I check everything. We've caught pharmacy mistakes before because the wrong amount was in the syringe. The more checks the better. Pharmacy is a great resource, but that doesn't mean you should administer meds blindly.

[direw0lf, BSN]

I got a 100 on kaplan dosages (it was basic but still had scenerios!) and a 98 on my class exam on pills to IV infusions and drip rate! I made a mistake with the calculator, typed the wrong number. But I'm feeling good!

I had to sacrifice some pathos studying but cramming it today.

[emtb2rn, BSN, RN, EMT-B]

We do a lot of math in the ed, especially with peds. Not uncommon to have the ed doc, the peds hospitalist & the rn doing calculations simultaneously to make sure we come up with the correct dose.

[sjalv]

Even if you use eMAR and scan meds you still do med math. What about when you're administering controlled substances from the pyxis? You need to figure out how much to draw up when you need to give 1.5 mg of ativan and you have a 2 mg/mL vial.

I don't know about other facilities, but the pharmacy profiles the ordered medication in the Pyxis along with the ordered dose. So when you go to pull it, it'll say "pull X vials". For example, for a 60mg dose of SoluMedrol, you'd select the 40mg SoluMedrol and it'd say "remove 2 vials". Then when you scan the med, it'll say "60mg = 1.5 mL". In your Ativan example, it'd say "1.5 mg = 0.75 mL".