# Dosage question ;)

1. For some reason I just cannot grasp the whole grains concept.... Can anyone help with this question? Order: atrophine sulfate gr 1/300 sc statSupply: atrophine sulfate 0.4 mg per mLGive: ? mL
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Joined: Dec '12; Posts: 2

3. 1 gr = 4-5 mg hope that helps
4. Or try it the long way- this always helped me to understand the concept & double check my answers. 1 grain = 60-65mg, you use whichever comes out with the even number usually. Unless instructed otherwise
5. Answer i believe would be 2ml. You use 1gr is to 60mg. So if it says 1/300 you would divide 60into 300 which equals 0.2. So 0.4mg is to x ml as 0.2 is to 1ml. 0.2x=0.4, 0.4 divided by 0.2 equals 2. I BELIEVE! But i did that in my head without double checking it so you definately should! Lol good luck
6. Quote from Kkccsr
For some reason I just cannot grasp the whole grains concept.... Can anyone help with this question? Order: atrophine sulfate gr 1/300 sc statSupply: atrophine sulfate 0.4 mg per mLGive: ? mL
This is the way I did it... I just passed my Pharmacology Mathematics exam last week 100%.

Atropine is a gr 1 = 60mg (the 64.8 standard has been phased out it seems and gr 1 = 65mg only applies to Acetaminophen and Iron -- as per my instructor).

gr 1/300 = 0.00333 x 60mg = 0.2mg
Using Order / Available (aka Desired / Have)...
0.2mg / 0.4mg x 1ml = 0.5ml

7. Lol yes^^^^^. See that why you dont do it in your head!! Ive always mad that mistake- x2 or divided by 2. Sorry!! : )
8. 1/300grain x 60mg/1grain= 0.2mg because 1/300=0.003grains which will be multiplied by 60 mg to get 0.2mg
0.2mg x 1mL/0.4mg= 0.5mL
9. I start school for the first time next week and looking at this is like reading German. I'm terrified of math and this thread didn't help. Lol hopefully i have a good instructor that will make it easy.
10. PookyP - there's a great video for drug dosages from Khan Academy, they don't have much yet but it's a solid start.