1. I have probably spent 3+ on this one problem. Cannot figure it out at all.

The order is for Amoxicillin 20 mg/kg/day. This is to be divided into doses to be given every 6 hours to a child weighing 11 lbs. If the medicine is supplied as a solution of 500 mg/2mL, how much would you give for each dose?

I know you are supposed to put the child's weight in kg and I got 5 kg for that. and I'm lost after that

Joined: Aug '08; Posts: 69; Likes: 3

3. 20mg / Kg/day * 11lbs/1 * 1Kg / 2.2lbs * 2ml / 500mg = 0.4 ml/day

-----> 0.4 ml / 4 = 0.1 ml /dose
4. how do you know how to set up those boxes? i think they are called "idiot boxes"? i dont get it

why did you divide .4 by 4 at the end?

you are right though, the answer is 0.1 mL
5. Ice Cream...You're an awesome person for helping this person with the answer.
6. First:

11 lbs /2.2 = 5 kg

then
20mg/kg/day = 20mg * 5 kg = 100 mg/day

then
500mg/2ml = 100mg/x
cross multiply you get 200 = 500x = 0.4 ml total dose/day

then since the dose is to be divided into 4 doses (every 6 hours)
0.4ml/4 = 0.1 ml per 6 hour dose

I think that's right.
7. bowingpur:heartbeat

you guys are so awesome. i love this forum, so helpful!!

MANY THANKS!!!!
8. Quote from JadenRN TO BE
how do you know how to set up those boxes? i think they are called "idiot boxes"? i dont get it

why did you divide .4 by 4 at the end?

you are right though, the answer is 0.1 mL
9. Quote from PrincessSpyder
Ice Cream...You're an awesome person for helping this person with the answer.
I did the calculation only, I did not explain it though....
10. Jaden, try visualizing the problem and see if that helps you understand the steps.

Imagine actually having that patient and that medication to give.
11. Hi there,

Now I"m don't do pediatrics, so I'm unfamiliar with their dosing, but based on your numbers, here's what I'm getting.

20 mg/kg/day as you point out this pt weighs 5 kg... Therefore the patient needs

20mg x 5 daily (100mg) in 4 equal doses = ammox 25mg every 6 hours

So your desired dose is 25 mg, what is your dose on hand?

500mg in 2cc = 250mg in 1cc ... Your dose on hand is 250mg/1cc

divide your desired dose by your dose on hand 25 divided by 250 = 0.1cc

Your patient needs 0.1cc of this ammox every 6 hours. Certainly a smaller dose than I am used too!

Hope this helps

From the white mountains of NH
12. The order is for Amoxicillin 20 mg/kg/day. This is to be divided into doses to be given every 6 hours to a child weighing 11 lbs. If the medicine is supplied as a solution of 500 mg/2mL, how much would you give for each dose?
Dose Desired: 20 mg/kg/day q6h (q6h means there will be 4 doses given over a 24 hour day)
Dose on Hand: 500 mg/2 mL
Child's Weight: 11 pounds
Conversion Factor: 2.2 pounds = 1 kg

By dimensional analysis (factor labeling): 20 mg (dose desired)/500 mg (dose on hand) x 11 pounds (weight of child)/1 kg (part of dose desired) x 1 kg/2.2 pound (conversion factor) x 2 mL (amount the dose in hand comes in)/4 (number of doses this needs to be divided into) = 0.1 mL (amount to give for one dose)