Can someone help with this calculation problem?


I hate to annoy people with asking a calculation question, because I'm sure most of you are as highly annoyed by them as me! Here is the calculation:

Add 40 units of Pitocin to 1000ml D5RL. Infuse at a rate to deliver 4 units of Pitocin per hour. How many mls per hour should you administer? (infusion pump)

Ok, you can't just straight add units to mL's, right? I have only had infusion pump problems with ml's so far, so this one is a little confusing to me! I have even tried googling similar problems with no luck. If anyone could help I would appreciate it so much!



12 Posts

I think you would need to know how many units of Pit per ml before you continue the calculation.


1,753 Posts

Specializes in Surgical, quality,management. Has 12 years experience.

100 mls per hour??

What you want 4 units/hr, what you have got 40 units therefore you have got 10 unit hrs, into a 1L bag is 100mls/hr. Pitocin is not a drug I am familiar with but it must be small volumes if you are counting in units.

Has 13 years experience.

I actually worked it by doing 1000 ml/ 40u X's 4u and got 100 mL, I just didn't think it was right! so I guess that is the right answer after all! THANK YOU!! :) :)


193 Posts

Specializes in Telemetry, Med-Surg. Has 1 years experience.

1000ml/40 units x 4 units/1 hr = 100mL/hr

loriangel14, RN

6,931 Posts

Specializes in Acute Care, Rehab, Palliative.

I use dose over what you have(doc over stock) 4 divided by 40 is 0.1.The you multiply by the volume.1000 x 0.1 = 100


203 Posts

Specializes in OB, House Sup, ER, Med Surg. Has 5 years experience.

This is an interesting problem, as we usually dose Pitocin in milliunit/min.


2 Posts

ok you always place what you are looking for on top so you can set it up this way

ML/HR = 1000ML/40 U mutilplied by 4U/Hr = unit cancels unit and you are left with ML/Hr. 100ml/hr


659 Posts

I agree the answer is 100ml/hr.

Have you learned 'desired over on hand' calculation? That's the only way I could ever do calculations. It's the easiest for me.


31 Posts

you have answered your own question 100ml/hour all to be delivered in 10hours...:)


240 Posts

You can do this in your head. The 4mL dose is 10% of the total 40mL that you put in the bag. You need to give 10% of the 1000mL bag per hour, which is 100mL. So give 100mL per hour.


4 Posts

The book" Drug Math in 4 easy steps". Is the simplest way to figure any drug problem. The 4th step is a drip. Any drip. It got this non math person thru Paramedic school. ANd we have to get 100% on the drug math to pass.