Please help with pediatric dosage calculation

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Hey, I need some help with pediatric dosage calc. I have two teachers that solve this problem differently and now I am confused and frustrated?

Doctor orders: Haldol (Haloperidol) 1 mg IM

Available: 50 mg/10 ml. Multidose vial, the young boy is 11 years old.

Teacher A) *uses Young formula*

step 1: 11/11+12x1mg= 0.47826087mg

step 2: 0.47826087mg/50mgx10ml= 0.09 mL

Answer: 0.09 mL

Teacher B) *says young formula is not applied*

1mg/50mgx10mL= 0.2 mL

Answer: 0.2 mL

So, is "Teacher A" correct or "teacher B"??

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Specializes in OR, Nursing Professional Development.

Let's just look at those two answers. How would you measure 9/100 of an mL when syringes only measure to 1/10 of an mL? That right there should be throwing a red flag.

I was taught desired divided by dose on hand times the volume. This is the formula teacher B used. It appears the Young formula should be used to calculate the dosage of a medication for a pediatric patient based on the adult dose. It would not apply when you already have the dose the patient should receive.

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1 hour ago, Michelle747 said:

[...]

So, is "Teacher A" correct or "teacher B"??

Teacher B is correct.

42 minutes ago, Rose_Queen said:

[...]

I was taught desired divided by dose on hand times the volume. This is the formula teacher B used. It appears the Young formula should be used to calculate the dosage of a medication for a pediatric patient based on the adult dose. It would not apply when you already have the dose the patient should receive.

Agree with all of this. Clark’s rule and Young's rule are both used to estimate pediatric dosing, based upon the adult dose. Clark’s rule uses the patient’s weight while Young's rule Sue’s the patient’s age. Even though pediatric dosing is based on the patient’s weight, in my opinion, there is no place for either of these formulas in calculating pediatric dosages. Medication doses should be calculated using an accurate patient weight as the difference between a therapeutic and possible toxic dose can be miniscule. The only situation in which an estimation should be made is in a code situation, using a weight based tape.

42 minutes ago, Rose_Queen said:

Let's just look at those two answers. How would you measure 9/100 of an mL when syringes only measure to 1/10 of an mL? That right there should be throwing a red flag.

[...]

This will vary from facility to facility, based on the syringes used. Where I work, our 1 mL syringes are graduated in 0.01 mL increments.

Best wishes.

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Specializes in OR, Nursing Professional Development.
2 minutes ago, chare said:

This will vary from facility to facility, based on the syringes used. Where I work, our 1 mL syringes are graduated in 0.01 mL increments. 

Interesting. We do not have these in my facility, unless they have some on peds (I've never even set foot on our peds unit).

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Specializes in Mental Health.

B.. you can do that in your head. 1 mL is 5 mg, 1/5th is 0.2.

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I think someone with an admirable sense of humor wrote the Clark's rule wikipedia page:

Quote

Clark's rule is not used clinically, but it is a popular dosage calculation formula for pediatric nursing instructors.[citation needed]

I am fine with never having heard of either of these formulas before.

What. ?

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4 minutes ago, JKL33 said:

[...]

I am fine with never having heard of either of these formulas before.

What. ?

I'll admit that I had to look them up as well. And I agree with the quote from Wikipedia that you posted, this is just another example of garbage that students are being taught by instructors that mostly don't have a clue.

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5 hours ago, Michelle747 said:

Available: 50 mg/10 ml. Multidose vial, the young boy is 11 years old.

Teacher A) *uses Young formula*

step 1: 11/11+12x1mg= 0.47826087mg

step 2: 0.47826087mg/50mgx10ml= 0.09 mL

Answer: 0.09 mL

This instructor has ignored the question entirely and arbitrarily decided to apply a formula that is bad practice and completely unnecessary to arrive at a decision to administer 0.45 mg even though the order was for 1 mg.

1
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3 minutes ago, JKL33 said:

This instructor has ignored the question entirely and arbitrarily decided to apply a formula that is bad practice and completely unnecessary to arrive at a decision to administer 0.45 mg even though the order was for 1 mg.

It does make one wonder, doesn't it?

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Thank you guys for your answers! So clinically you guys don’t use Clark’s, Young’s or Fried’s rule?

Also, can you recommend me a good book for pediatric dosage calculation that teaches me how to do it the right way?

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13 hours ago, Michelle747 said:

Teacher A) *uses Young formula*

step 1: 11/11+12x1mg= 0.47826087mg

step 2: 0.47826087mg/50mgx10ml= 0.09 mL

Answer: 0.09 mL

This must be that "new math" everyone talks about. And it's completely wrong. ?

1
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6 hours ago, Michelle747 said:

Also, can you recommend me a good book for pediatric dosage calculation that teaches me how to do it the right way?

The right way is to determine the dose based on the patient's weight in grams/kilograms and then apply your normal drug calculation formula. For example:

You have a 15lb infant that needs Tylenol. Tylenol dosing is usually 10mg/kg. Tylenol concentration available is 160mg/5ml

1. Convert weight from pounds to Kg (go ahead and round up if appropriate)

2. Determine dosage based on weight in Kg

3. Plug that number into your standard equation.

Try it and see what you get. We'll help if you get stuck.

And I have never seen or used any of those "rules" in my practice. In this day and age they are absolute rubbish.

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