Calculations

Yeah it was written as same.. that's may be why I'm not getting it.. It was written to continue IV for next 36 hours

Hi everyone

I need help in drug calculation. I read a drug question and I'm not getting the right answer. I have to give 40 mg pantoloc at 8mg/hr for next 36 hours. How to dilute and how many mg/ml is?? . Nd in order to keep doctors order 8mg/hr for 36 hours what should be the rate???

I'm going to presume that the error is that you *have* 40mg vials, which is the standard vial of pantoprazole. With that presumption, the order makes sense academically and would be a legitimate clinical order.

Per Davis Drug Guide, desired concentration of solution is 0.4 mg/mL - 0.8 mg/mL so reconstitute the 40 mg vial in a 100 mL bag to get:

40 mg / 100 mL = 0.4 mg/mL

to get 8 mg/hr:

(8 mg/hr) / (0.4 mg/mL) = 20 mL/hr which would mean that you'd have to change bags every 5 hours...

Now being the efficient nurse-to-be that you are, you recognize that making a new bag every 5 hours is kind of a hassle so you decide to use the higher concentration listed in the Davis Drug Guide: 0.8 mg/mL

So, you reconstitute two 40 mg vials in a 100 mL bag

80 mg / 100 mL = 0.8 mg/mL

(8 mg/hr) / (0.8 mg/mL) = 10 mL/hr so now you've got 10 hours worth.

Now, regarding that 36 hour number... the reconstituted solution is only stable for 24 hours so it's a no-go right off. But, just for mathematical kicks...

(36 hr) x (10 mL/hr) = 360 mL of your 0.8 mg/mL solution... Well, there isn't such a bag available... but you could use a 500 mL bag and that would have sufficient volume to run at 10 mL/hr for 36 hours (with 14 hours to spare...)

So, how many vials of 40 mg pantoprazole must be reconstituted in that 500 mL bag?

(0.8 mg/mL) x (500 mL) = 400 mg of pantoprazole

How many vials do you need to get 400 mg?

(400 mg) / (40 mg/vial) = 10 vials

Alternatively, say you don't want to have to worry about stopping the infusion after 36 hours with medication remaining but rather preferred to simply give the whole bag over 36 hours...

(8 mg/hr) x (36 hr) = 288 mg total to be infused over 36 hours

(288 mg) / (500 mL) = 0.576 mg/mL (which is within the referenced range from Davis Drug Guide)

Now, how fast to run it?

(8 mg/hr) / (0.576 mg/mL) = 13.9 mL/hr

A quick sanity check: (13.9 mL/hr) x (36 hr) = 500 mL

Now, how many vials makes up 288 mg?

(288 mg) / (40 mg/vial) = 7.2 vials

I really have no clue what your teacher is actually looking for but all of these permutations pretty much cover how to attack a problem like this.

However, as I said: The solution is only stable for 24 hr so it's impossible to safely do this in a single bag.