Math Help? What is the correct answer.

TazziRN, RN · Jun 13, 2006

I won't give you the answer but I'll give you the formula. Convert the pounds into kilos. Multiply by the dose per kilo. That will be the total dose in 24 hours. Divide that by 2.

shady_angelz · Jun 13, 2006

Ok well we had this exact question for my comp testing. I did 50*30. You get 1500. And then I did 1500 divided by 2. I got 750. However, it was wrong.

rhapsodyRN · Jun 13, 2006

Can anyone tell me the answer to this problem.
The physician orders ceftriazone sodium 50 mg/kg of body weight, in divided doses every 12 hours for a child who weghs 66 poinds. Calculate the body weight, then determine how many milligrams will the child receive in each dose?
Thanks in advance

Divide 66 pounds by 2.2 to get kilograms. In this case, the body weight would be 30 kg. If the dose is 50mg/kg, then you will multiply 30 by 50 to get 1500 mg. Now, since the dose is twice daily (q12h) then you will divide the 1500 by 2, which will give you 750 mg per dose.

Hope that helps!

rhapsodyRN · Jun 13, 2006

Or not. :)

Maybe they're considering the 50mg/kg to be each dose? In which case you'd end up with 3000 total and 1500 for each dose?

TazziRN, RN · Jun 13, 2006

Ok well we had this exact question for my comp testing. I did 50*30. You get 1500. And then I did 1500 divided by 2. I got 750. However, it was wrong.

In that case you need to have a talk with the instructor or whoever gave the test, because 750 is right.

*CJA* · Jun 13, 2006

66 lbs/2.2 = 30 kg body wt

50 mg x 30 kg = 1500 mg/day

1500mg/2 = 750 mg/dose

I have seen this type of problem on many med calc tests. Must be able to do them!!

tulip928 · Jun 13, 2006

Can anyone tell me the answer to this problem.
The physician orders ceftriazone sodium 50 mg/kg of body weight, in divided doses every 12 hours for a child who weghs 66 poinds. Calculate the body weight, then determine how many milligrams will the child receive in each dose?
Thanks in advance

There's a problem with this order! It does NOT specifiy whether this is 50 mg/kg per day or 50 mg/kg per dose. In the real world, you would need to get the doctor to correct the order.

*CJA* · Jun 13, 2006

There's a problem with this order! It does NOT specifiy whether this is 50 mg/kg per day or 50 mg/kg per dose. In the real world, you would need to get the doctor to correct the order.

You are right, but this is a test question, not real world. Why would it say "divided doses" if it was per dose? I think it has to be per day.

But then, the OP says it's getting marked wrong.

All I can say is I'm glad I'm not in that class, 'cause there's probably going to be a big fight over this one.

*CJA* · Jun 13, 2006

Ok well we had this exact question for my comp testing. I did 50*30. You get 1500. And then I did 1500 divided by 2. I got 750. However, it was wrong.

OK, well I would go to the instructor or TA and politely ask to see the problem correctly worked out.

TazziRN, RN · Jun 13, 2006

The question specifies the individual dose. The 50mg/kg has to be for a daily dose because otherwise it would come out to 1500mg per dose....way too much for a 30kg kid.

ukstudent · Jun 13, 2006

Child's weight is 66 lbs / 2.2 = 30 kg

50mg x 30 kg = 1500mg of ceftriazone sodium.

q12hrs, 1500 / 2 = 750mg per dose.

Math question get a lot harder than this. If this question is causing you problems then you need to get a dose calculation class now. At least get a book and do question after question until you feel confident.