Math check on dosage calculation, please!

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Problem reads:

You need to give Ceclor to a patient who weighs 31 pounds. The doc order is Ceclor 20 mg/kg/day in 3 divided doses. You have Ceclor available in 125mg/5ml. How many ml will you administer in each dose?

31lb/2.2kg = 14.1 kg

5ml:125mg::x:20mg

100 = 125x

100/125 = 125x/125

0.8 = x

0.8ml 3X a day

Is this right? Is there a more streamlined way to set it up? Thank you!!!:confused:

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

you need to give ceclor to a patient who weighs 31 pounds. the doc order is ceclor 20 mg/kg/day in 3 divided doses. you have ceclor available in 125mg/5ml. how many ml will you administer in each dose?

by dimensional analysis. . .

20 mg/1 kg
(dose to give)
x 31 pounds/day
(part of dose to give)
x 1 day/3 doses
(one dose)
x 5 ml/125 mg
(dose on hand)
x 1 kg/2.2 pounds
(conversion factor)
= 3.75 ml/dose
rounded up to
3.8 ml/dose

you can also recheck this using another method. 31 pounds converted to kilograms is 31/2.2 pounds, or 14.090909 kg. insert that into your order
20 mg/kg/day in 3 divided doses
so you have (20 mg) (14.090909 kg) (one day) which gives you a required dose of 281.818181 mg.

dose desired: 281.818181 mg

dose on hand: 125mg/5ml

calculate using the formula
dose desired divided by the dose on hand multiplied by the amount the dose on hand comes in
: 281.818181 mg/125mg x 5ml = 11.272727 ml. this is the daily (24 hour) dose. to get one dose, divide this by 3: 11.272727 ml/3 =
3.7575756 ml
which you would round off.

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I get 11.2ml, divided into 3 doses is 3.7ml

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Specializes in Cardiac, Derm, OB.

i get 3.76 which per our rules rounds to 3.8ml per dose

here is the da:

ml= 5ml/125mg x 20mg/1kg x 1kg/2.2# x 31#/3 = 3100/825 = 3.76

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