calculating drugs doses


Hi, I am hoping for some help. I am a C.C. RN though I have been oow d/t a back injury for more than 2 years. I am going through my critical care class notes and realize that I do not remember my formulas for calculating drugs. I only remember .. desired dose over have on hand.. I have forgotten the rest. Also I don't seem to remember my calculation for mcg/kg/min.

Help please.

I will be going back to the unit pretty soon.

Thank you.


35 Posts

are you still needing the equation for drug calcs. I bought a PDA that could help me out in a pinch but I will resurrect the equation if you need it....

Catfish RN

34 Posts


I do still need them. Thank you for your help.

Specializes in Home Health, Primary Care. Has 18 years experience.

I don't really work with formulas, but if you need mcg/kg/min, just divide by the patient's weight (in kg of course) once you have the answer in mcg/min.


388 Posts

Specializes in CCRN, CNRN, Flight Nurse. Has 10 years experience.

I wish I could link what my school teaches, but the site is password protected. I can copy/paste or email if you are interested. Also have a bunch of practice problems.


4 Posts

This is a really old formula but it really does work, it came from a AACN publication about 15 to 20 years ago but it works.


_____ X 16.7 divided by weight in KG = then times rate


will equal mcg/kg/min

example: dopamine 800mg in 250cc= 3.2 X 16.7=53.44 divided by 75kg

equals 0.71( this is your cal factor)x rate say 15cc gives a

answer of 10.6mcg/kg/min

I don't remember where the 16.7 comes from but this formula does work I have kept it on a sticker on the back of my calculator since I found it many years ago and it always matches the answer the new nurses get with their new formulas.

Hope you get back in the swing of things okay.

from a really old ICU nurse who is still going strong.:

Catfish RN

34 Posts

Thnak you all for your help.

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