Help! Stuck on 2 dosage Qs...

1) 1 grain=?mg?...so 1/6 grain = how many mg?....than the dose on hand 15/1 : dose required/x

2) how many ml/minute...100/60....then microgtts per ml

for some reason I can't figure out these 2 problems. I have the answer but don't know how they got it....

1:

The nurse administered the ordered PRN dose of grains 1/6 morphine sulfate SC. The vial of morphine contains 300mg in 20mL. The nurse drew up______mL into the syringe

I know the answer is 0.7mL

2:

200mg of aminophylline in100mL D5W is ordered to run in over 60 minutes. The nurse will set the drip rate at ________microgtt/min.

the answer is 100microgtt/min

Can anyone show me the breakdown on how to get the answer???? THANKS!!!

1. The morphine comes in 1/6 of a grain. So you turn 1/6 into a decimal first. Which is 0.167gr

Then you set it up to cancel out the units

remember 65mg=1gr

0.167gr x 65mg x 20ml = 0.724 or 0.7ml

1 vial ````1gr `` 300mg

remember here that 60microgtt=1ml(i had to look that one up, i knew 15gtt=1ml. but didn't know about microgtt:confused:)

2. 100ml x 60microgtt = 100microgtt/min

```60min ````1ml

Hope this helps, PM me if you have any questions. :typing

You Rock! Thanks!!!! I ended up figuring #2 out on my own but #1 still threw me. *&^% nursing school we haven't even gone over grain conversions yet...leave it to nursing school to throw something in a test that you have not gone over yet...God Forbid if we were to get a 100%!! Sorry, venting..