Dosage Calcs

  1. I start my LPN program on Friday. I had taught myself how to do drug calcs using the D/H x Q. I was told by our instructor last week that we would not use that formula, we would be using dimential analysis. I have been learning those, but it seems harder. Everything I have read says this is math for dummies and it is really simple? Any advise?
    Lorrie
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  2. 9 Comments

  3. by   SuesquatchRN
    I don't know what either of those are, but drug calcs are definitely math for dummies. Ex: Order calls for 650 mg Tylenol. You have 325 mg tablets on hand. How many pills does the patient get?

    Some stuff is a bit more complicated but really, it ain't rocket science.

  4. by   Laura77598
    Hi Lorrie,

    I'm in the same boat as you. I have been teaching myself the D/H xQ method and all the other necessary formulas needed for IV calculations, and OUR teacher says we will be learning Dimensional Analysis instead. What a Joke ! I now understand DA, but I'm so much more comfortable with formulas!!! I grew up with formulas. everymath class I have ever had has taught formulas! Seems to me there is a new era where nurse educators are heeding and conforming to the winds of change and the belief that if drug equations can be made into ONE HUGE GIGANTIC STEP that no student will leave anything out or get the calculation wrong! Personally I don't agree. I prefer the formula method myself. I think DA is being taught more often because it puts ANY conversions your may need to perform into the LOOOOOOOOOOOOOOONG equation!!

    Me, I like formulas. I can remember to convert the values and stuff before I plug the data into a formula. I don't like DA because I never learned it for ANYTHING except this class!!! MUST BE A REALLY IMPORTANT WAY TO TEACH MATH , HUH????? Anyway, I kinda see why the instructors are changing their instructions, but multiplication and division are still just multiplication and division. When I take the class, I will STILL use the formulas, because they are time-saving for me. I have trouble remembering why one number goes in one place and others go in other places. I need a reason to put some number on the bottom. (a reason that isn't to cancel out the next number.) That just seems like MUSICAL CHAIR MATH to me. I prefer formulas, and I am going to keep using them. I will convert my values before I use the formulas if necessary, but DA is just too much work to learn when the formula method works just as well.
    We are using ANNA CURREN's Dimensional Analysis for Meds. as our text. I have bought the book early, and a book that teaches formula & DA& R/P methods also, and I still find the formula method easier. That;s what I'm stickin'to. I will take my class online this summer, and she can't mandate me to perform the calculations using one method over another, and she can't get problems that won't work only with the DA approach. I would recommend that you buy some different books that use all of the approaches and then get a Dimensional Analysis book and see if you can work the problems using both methods. I can, but formulas are just quicker for me. like painting something free handed vs using a stencil. The stencil is quicker, easier, and gets me the result I want. Just remember to perform your conversions before you begin your problems. Make sure your units agree, if not convert them and then plug in your values to the formula.

    Most bilingual people can speak in 2 languages rather fluently, but most of them still revert to their mother tongue when at home because it was what the first learned, and the one they are the most comfortable using. The messages are still understood and effective, so what is the problem.

    I'm bilingual, but Formulas are my first language, and the one I'm most comfortable using. And if my answers are the same as the DA method, she can't count off for it. We don't have to show our work, we just have have the right answer.

    Good Luck,
    Laura77598
  5. by   Jules A
    Beware of the D/H X Q method. I also thought it was much easier than using the Ratio Proportion method. In my experience D/H X Q does not always work out correctly which might be why your professor isn't teaching it. Once I got used to using the RP method I found it very easy.
  6. by   midcom
    Before starting school I bought the Demensional Analysis book because it was recommended & started reviewing & learning. Yesterday I started Pharmcology & guess what? We are using D/H X Q and I so much prefer it. It just came naturally for me.
    Funny thing is that the book we are using is also by Anna Curren, it ju doesn't use DA.
    Dixie.
  7. by   LorrieAnn
    Thanks so much for the replies. I personally like D/H=Q as well. I guess I can try both ways.. but the DA takes fffffoooorrrrreeevvveeerrr to do! I am excited to start class on Friday. Has anybody here done the week-end program? That is what I am doing.
    Lorrie
  8. by   We'llSee
    Quote from Jules A
    Beware of the D/H X Q method. I also thought it was much easier than using the Ratio Proportion method. In my experience D/H X Q does not always work out correctly which might be why your professor isn't teaching it. Once I got used to using the RP method I found it very easy.

    I've been lurking at this site for a bit, decided to join, and this thread (particularly this post) prompted me to stop lurking and start posting.

    We were given the option of both ways of calculating, and then were told to do what we each personally preferred. I opted for D/HxQ=A. Jules, why do you say this doesn't always work out? I'm very interested in your experience with this.
  9. by   Jules A
    Quote from We'llSee
    I've been lurking at this site for a bit, decided to join, and this thread (particularly this post) prompted me to stop lurking and start posting.

    We were given the option of both ways of calculating, and then were told to do what we each personally preferred. I opted for D/HxQ=A. Jules, why do you say this doesn't always work out? I'm very interested in your experience with this.

    I'm not sure if it has something to do with the order you are dividing and multiplying or what but it was our experience in class that you could run into trouble on some problems with this method. Our dosage exams were either 10 or 20 questions so you couldn't afford to miss anything. Our Professor was super particular so its possible that it just messed up our final answer with the rounding factor maybe but I don't know for sure. In any event thats why I taught myself the means/extremes that she wanted us to use. Its interesting that some professors aren't allowing it to be used and some books are using it either. I wish I could be of more help and I also wish I had saved some of the examples, like I said it wasn't all the time just sometimes. I just thought I would share my experience and folks can do what they want of course.
  10. by   Yin Yang
    Dimensional Analysis is also used in Chemistry classes. Once you get used to it, it really is a very functional and efficient way to do your calculations. Give it an honest try, as you never know when it might come in handy!

    Take Care,

    Kathy
  11. by   We'llSee
    Thank you Jules and Kathygalt. My books offer it both ways and I will take your advice and take another peek at the other way of calculating (means and extremes), and I'll compare the answers... an especially good idea as I've got a test coming up and there will be some of this on it.

    This is one area that I want to make sure I've got down cold, as well as accurately.

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