dosage calculations questions: Who's wrong, me or the study guide?

KerriN · Apr 9, 2005

I guess those are the kinds of details you learn in addition to the math. Do you all think it's critical that I take the course, or does knowing how to convert measurements and do the dimensional analysis enough? The math part comes easy for me, but I'm kind of afraid I might miss something important. On the other hand, freeing up hours of my time to concentrate on clinicals sounds really tempting. I have a husband, & 7, 5, &1 yr olds at home, too. Not to mention paying for child care for all of them.

Sheri257 · Apr 9, 2005

You are right. Study guide is wrong. :)

On a side note, I've just about given up on study guides because of situations like this.

You spend more time trying to figure out what's going on with these wrong answers. All it does is confuse you.

:banghead:

RN4NICU, LPN, LVN · Apr 9, 2005

I agree with suzanne on this. Any study guide that tells you to go with the manufacturer's recommendations OVER the MD order should be tossed out the window. The NCLEX is going to go with the MD order every time because adjusting the dose to fit the manufacturer's recommendation (or anything else) is beyond the RN's scope of practice. If there was an option for a similar question that said call the MD and clarify, I would definitely pick that one (I've certainly called enough docs to clarify dosages throughout my career). But if not, always go with the order.

KerriN · Apr 9, 2005

I'm going to post another one because I know I'm wrong but I don't know why.

Order:Digoxin 0.012 mg/kg po qd

Child weighs 13 lbs

Label: each mL contains 50 micrograms (0.05mg)

How many milliliters would you prepare?

Answer: .312 = .3mL

My calculations:

5.91 kg x .012mg = .07mg .07mg x 1mL/.05mg = 1.4mL

I know this is wrong because the label has you draw a line on the dropper according to the dose, and the dropper only goes to 1.0 mL. But I can't see where my math is wrong. Can anyone help?

suzanne4, RN · Apr 9, 2005

First, as previously stated, get rid of this book.

At no time, EVER, EVER, do you use the dropper that comes with liquid medications in a hospital. And never, ever with digoxin. This dose is calculated in very small amounts and could be dangerous if the child gets an overdose. From that standpoint alone, I would toss the book.

Now, to your question............the weight translates to 5.9 kg. Multiply this by the amount per kg, which is 0.012mg..The result is 0.07 mg. Your drug comes in 0.05mg/ml, so the answer is 1.4 ml. The book is wrong......Simple as that.

With the new JCAHO laws that have come into being, always put a zero before the decimal point, if the number would be less. If the number is whole, never put a zero after the decimal point, or even use a decimal point. This kepps down medication errors.........

KerriN · Apr 9, 2005

First, as previously stated, get rid of this book.
At no time, EVER, EVER, do you use the dropper that comes with liquid medications in a hospital. And never, ever with digoxin. This dose is calculated in very small amounts and could be dangerous if the child gets an overdose. From that standpoint alone, I would toss the book.
Now, to your question............the weight translates to 5.9 kg. Multiply this by the amount per kg, which is 0.012mg..The result is 0.07 mg. Your drug comes in 0.05mg/ml, so the answer is 1.4 ml. The book is wrong......Simple as that.
With the new JCAHO laws that have come into being, always put a zero before the decimal point, if the number would be less. If the number is whole, never put a zero after the decimal point, or even use a decimal point. This kepps down medication errors.........

When I was talking about the dropper I was referring not to an actual one, but one drawn on the drug label. But that's interesting that you found my answer correct, anyway. That makes me feel a little better about my math. As far as the 0's go, I was just being lazy with my typing. I've learned my lesson :) Thanks suzanne for all your input.