Dosage Calculation

BacktotheBeach, ADN, BSN, RN · Jul 14, 2010

You don't need the info about the 20 dose vial.

I set it up like this:

100 mg = 200 mg then multiply, on one side you get 200, the other is 100x

1 mL X mL

Then you divide 200 = 2 mL

100

You give the patient 2 mL to get 200 mg. Hope this helps.

(It is really hard to get my equation to stay when I post!!)

here is a good website

http://www.dosagehelp.com/

BacktotheBeach, ADN, BSN, RN · Jul 14, 2010

OK, sorry but I can't get my equation to line up, it moves when I post it. Hopefully you can see what I am showing. Directly under 200 mg should be X mL. Then below that under 200 it should be divided by 100. UGH Frustrating.

panaya · Jul 15, 2010

I do what do you need over what do you have times volume.

for example you need 200mg you have 100 mg and the volume is the/ml= 1 ml

sooooo

200

---- x 1 = 2ml:) does this help?

100

Corlee · Jul 18, 2010

I always say what I need over what I have. You need 200mg of medication and what you have is a concentration of 100mg/ml.

So 200mg/100mg= 2ml

Hope that helps!

healthstar, BSN, RN · Jul 19, 2010

Dose ordered: 200mg IM Tigan
On hand: 20ml multidose vial; 100mg/ml
Give patient: ____ml
please calculate it out for me so that I can see how it was solved. Thank you.

I find it easy to remember it this way.

D= doctor's order

H= Have on hand ( what you have available in the hospital)

V= vehicle ( per ml)

----------------------------------------------------------------------------------------------

D= 200mg IM Tigan

H= 100 mg

V= 1 Ml ( you assume there is a 1 in front of ml)

200mg/100mg * 1ml=

( zeros cancel)

and you are going to have

2mg/1mg * 1ml = 2 ml

I hope this helps :)