Can't wrap my head around these kinds of questions...

[nurse01.01]

1. Patient will be receiving a dose of an IV medication. It is to be reconstituted with 1.8 mL on NS to yield a volume of 2 mL. If the vial label indicates that there are 125 mg in the vial, calculate how many mLs you will prepare if the doctor has ordered 62.5 mg.
   

For some reason I always have such a silly time wrapping my head around these kinds of questions - I got 1ml but I am assuming I am not doing it right! Please help :)

[dudette10, MSN, RN]

It is correct.

Don't get all caught up in the amount to use to reconstitute and allow that to throw you off. Think of it in two distinct parts.

In real life, you would 1) reconstitute with the recommended amount of the correct solution. Now, forget about that part. You're done mixing, so you don't care anymore about the amount you used to mix. In your example, you used 1.8 ml of NS. Fine. Done.

Then 2) you move on to calculating your volume to administer. You first need to know the number of mg in the total volume. Ok, you have 125 mg in 2 ml. Order is for 62.5 mg. The math is easy. So, 1ml is correct.

[nurse01.01]

It's always the wording! As soon as i reread a couple of times it was so clear! Thank you for the reply :)!

[loriangel14, RN]

Just remember "doc over stock". Doc = what is ordered, stock=what you have on hand. 62.5 divided by 125 =0.5. Then you multiply by the volume. 2ml divided by 0.5 is 1 ml.

[nurseprnRN, BSN, RN]

Just remember "doc over stock". Doc = what is ordered, stock=what you have on hand. 62.5 divided by 125 =0.5. Then you multiply by the volume. 2ml divided by 0.5 is 1 ml.

Actually, 2 ml divided by 0.5 is FOUR-- there are four halves in two.

The question asks for 125mg in 2cc to be divided by 62.5mg, and the answer is 0.5 of the 2ml, or 1ml.

[loriangel14, RN]

Ooooops I meant MULTIPLY by 0.5 !:)