Drug Calc Question HELP?

Question

You are to reconstitute one gram of celphalexin with 5 cc of normal saline. The doc order is given a one time dose of 350mcg of cephalexin per gravity drip. (Out of electrical pumps). After reconstituting the medication, you draw up 1.8 cc of the reconstituted cephalexin to futher mix with 30cc of normal saline. How many drops per minute will you set the gravity drip (15 drops per cc) to facilitate a safe infusion at 30 minutes?

Answer 1

1 gm = 1,000,000 mcg
so
after reconstitution you have 1,000,000 mcg in 5 cc of ns

Here's your first formula

dose ordered
----------------- x Vehicle (liquid or tablet) = dose to give
dose on hand

350 mcg
-------------- x 5cc = 1.75 rounded to nearest = 1.8 cc
1,000,000 mcg

so far so good

here's your second formula

amount of fluid x drops/milliliter (IV set)
-------------------------------------------------- = gtts/min
hours to administer x minutes/hour (60)

32cc x 15
-------------- = 16 gtts/min
.5 x 60

If you keep these two formulas in your head (or in your pocket!) you will be able to calculate any dose. Just plug in your values and you have the answer.