Favorite formulas for drug and IV calculations

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Hi Everyone,

I am starting my program in 10 days and am still worrying about the math. I've been out of school for a long time and have taken math courses (got an A and a B), but reading my drug calculations book, there are so many different ways to figure out the solutions. If you could give me some examples of the formulas you prefer and why, I'd really appreciate it. Is there one over another that you would have a less-likely chance making a medication error? That is my biggest fear. I know there is no room for error when it comes to giving medications. Thanks. :)

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Specializes in Emergency Nursing.

Ordered Dosage/ What you have on hand * The Route of administration = What you give

Works with Liquid meds and pills

Say you have an order for 500 mg Tylenol liquid and what you have is 250mg per 5 mL

Set is up like 500mg/250mg*5ml and you get 10mL That's what you give.

Works the same with pills only your "Route" is always 1

Drip rates are easy

(Ordered Amount * Conversion factor of tubing) / Time in minutes to be administered over = drip rate

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Specializes in Medical Surgical/Addiction/Mental Health.

I have attached a sheet I pass out to my students. I always use the ratio proportion method. I find it to be easier. You will just have to play with the different methods and determine which method works for you. :D:D:D

dosagecalculations.pdf

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Thank-you both very much. Parker Bean Curd, great hand-out! I printed it out already. Don't get me wrong, I have my drug calculation book and am practicing out of that, but I like to get other opinions on what may make it just a little easier. Thanks again!

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I just took my final for my med math class today and they taught us dimentional analysis - which I found very easy to understand and calculate...

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Dimensional Analysis all the way for me. So easy! I struggled with math in prereqs but dosage has been a breeze for me thanks to using the dimensional analysis method.

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Perhaps my math study guide shall help.....best of luck

nclex math study guide.doc

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How you determine the answer is up to you. I prefer the ratio/porportion method while the school insisted on dementional analysis. I observed others in the class struggling with dementional analysis but thrived on ratio/porportion. Whatever math process you use, the bottom line is: did you get the correct answer?

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Dimensional Analysis all the way for me. So easy! I struggled with math in prereqs but dosage has been a breeze for me thanks to using the dimensional analysis method.

did you use a book to teach you the dimentional analysis method? I just ordered "calculate with confidence" and am hoping it has enough of the dimentional analysis method because I hear about this one the most.

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Specializes in Med Surg - Renal.
Hi Everyone,

I am starting my program in 10 days and am still worrying about the math. I've been out of school for a long time and have taken math courses (got an A and a B), but reading my drug calculations book, there are so many different ways to figure out the solutions. If you could give me some examples of the formulas you prefer and why, I'd really appreciate it. Is there one over another that you would have a less-likely chance making a medication error? That is my biggest fear. I know there is no room for error when it comes to giving medications. Thanks. :)

Learn all the ways they tell you in the dosage calc book, then pick your favorite.

My favorite has always been dimensional analysis. For me, (me only, not necessarily everyone) there is far less chance of me screwing it up.

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Dimensional analysis. I found the ratio/proportion method confusing. But I agree that you should find what works best for you.

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Thanks for all of the replies and worksheets!

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