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Math- 1:1000 calculations


Specializes in Gen Surg, Ortho, Urology, Vascular. Has 3 years experience.


I've recently accepted a new job in a new hospital. In order to give medications, I have to complete a medication quiz. I'm having trouble with a question similar to this:

How many milligrams of Adrenaline are there in 2 mls of 1:1000 solution?

I've been working it out like this:

1 part adrenaline=1000 parts solution

1g/1000 mls

1000mg per 1000 ml solution

1 mg/ml x 2 mls = 2 mg

Am I on the right track? I've been using the following website for guidance, but could certainly use more help/guidance to wrap my head around these! http://www.nda.ox.ac.uk/wfsa/html/u13/u1306_01.htm


Edited by jbee

nurse2033, MSN, RN

Specializes in ER, ICU.

You have the right answer. It doesn't matter how you solve the problem as long as you get it right. So solve this one: you put 1mg epi in 250ml normal saline, what is the concentration?......

To solve it start here- 1mg/250ml then multiply x 4/4 (to bring the volume up to a multiple of 10) which gives you 4mg/1000ml, now to find how much in 1ml-divide both by 1000 which gives .004mg/ml or 4micrograms/ml. Since the dose for an epi drip is 1-10ug/min that means you give a vol of 0.25ml-2.5ml/min (15-150ml/hr or 15-150 drops per min in a microdrip set). Probably more than you need to know but always good to review. Good luck.


Specializes in Gen Surg, Ortho, Urology, Vascular. Has 3 years experience.

Thank you for your help (and for the extra practice question).

Remember it's all metric. 1:1,000 is 1 gram in 1,000 ml or 1 mg per ml.