Pharmacy IV drip calculation
by John D
An IV has been ordered to run for 4 hours at 10gtt/min with a drop factor of 20 gtt/ml. The solution in the bag is 750mg of active drug dissolved in .5L of D5NS. How many mg of the active drug will the patient receive in two hours?
A. 45 mg
B. 60 mg
C. 90 mg
D. 120 mg
This is question #1 from free quiz #4. It has a fair amount of fluff to de-code thru. It's a good example of what you coud expect on the PTCB or ExCPT exam. So, first write down all necessary factors, and then work toward the unknown variable.
Here's one way to do it:
First, convert hours to minutes:
2 Hours = 120 Min
Then, Figure out how many drips will drop in that time :
120 Min x 10gtt/min = 1200gtt/duration
Next Divide the drips by how many make up an mL :
1200gtt ÷ 20gtt/mL = 60mL
Lastly, Set-up a quick conversion against the IV solution :
750mg - - - - X
-------- = ---------- cross-multiply for X
500mL - - - 60mL
Now, your turn...