# Newbie here...need some help with some math X_X

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Hello~~ I'm new around here, just started nursing school and so far I've managed to survive the 1st semester Anyway, I need some help with a practice test that they gave us for peds, its nothing that I've seen before and I've tried using some formulas but I'm not sure if that's the right way of doing it

so here's the problem:

Doctor ordered Kantrex 0.25 gm (grams? ) IV q8h for a 2 yr old weighing 26 lbs. What is the dosage for 24 hrs? Is this a safe dose if the PDR recommends 15mg/kg/day?

So I'm not sure how to answer the first question because I could use some of the formulas I know, but it requires me looking up the recommended adult dosage and I'm not sure they'd allow us to have our drug book when we take the test. I do know (I think) that to get the safe dose, I need to convert lbs to kg and multiply by the recommended safe dose

here's another one:

order Amoxicillin 150 mg po q6h for a child weighing 38 lbs. What is the dosage for 24 hrs? Is this a safe dose if the PDR recommends 20-40 mg/kg/day?

Sorry for the excessively long post :imbar hope you all don't mind, I'd really appreciate the help :balloons:

Thank you!!!!

26,410 Posts

You actually have all of the information there that you will need. No reason to need a drug book. Your instructor has given you all of the information.

Step 1: the child weighs 26lb. Divide that by 2.2 to get the number of kg which is 11.82

Step 2: 0.25 grams is the same as 250 mg.

Step 3: 250 mg IV every 8 hours means 750 mg/24 hours.

Step 4: PDR recommends 15mg/kg/day.

Step 5: The baby weighs 11.82kg, so 11.82 x 15 = 177.3mg. The dose is not a safe dose for that size child.

Second problem:

Try working it out the same way and pleas let me know what you come up with.

Hope that this helps. Remember that you have to start by converting child's weight into kg, before doing anything else.

:balloons:

5 Posts

ooooooo, ok now I get it :rotfl: (duh) Thanks!~

I worked out the 2nd one and here's what I came up with (hopefully I got it right )

order Amoxicillin 150 mg po q6h for a child weighing 38 lbs. What is the dosage for 24 hrs? Is this a safe dose if the PDR recommends 20-40 mg/kg/day?

150 mg x 4 = 600 mg/24 h

38 lbs/2.2= 17.27 kg

17.27kg x 20-40 mg/kg/day = 345.5-690 mg/day so its a the dose to be given is safe since it falls between the safe range

1 Article; 2,334 Posts

Thank you suzanne and dazed, I don't feel up to working the math problems right now but you can add my vote to the formulas & calculations looking correct.

26,410 Posts

ooooooo, ok now I get it :rotfl: (duh) Thanks!~

I worked out the 2nd one and here's what I came up with (hopefully I got it right )

order Amoxicillin 150 mg po q6h for a child weighing 38 lbs. What is the dosage for 24 hrs? Is this a safe dose if the PDR recommends 20-40 mg/kg/day?

150 mg x 4 = 600 mg/24 h

38 lbs/2.2= 17.27 kg

17.27kg x 20-40 mg/kg/day = 345.5-690 mg/day so its a the dose to be given is safe since it falls between the safe range

Good job.................. :balloons:

Once you do a few they are actually quite easy................. :)

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