oh my gosh, Can someone please help me with this drug calc problem??

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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 :(

someone please help, im goin crazy!

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

-----> 0.4 ml / 4 = 0.1 ml /dose

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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

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Ice Cream...You're an awesome person for helping this person with the answer. :)

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Specializes in Adult Oncology.

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.

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:bowingpur:bowingpur:yeah::redbeathe:heartbeat

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

MANY THANKS!!!!

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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

SolaireSolstice answered your questions. :)

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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....:)

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Specializes in Telemetry & Obs.

Jaden, try visualizing the problem and see if that helps you understand the steps. :)

Imagine actually having that patient and that medication to give.

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Specializes in Critical Care.

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

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Specializes in med/surg, telemetry, IV therapy, mgmt.

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)

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