1. Pediatric Dosage Calculation
Professor Shaffer

2. How is Pediatric Dosage Calculation Different than Adults?
There is no standard dose
All doses are based on a recommended dosage based on:
Body weight in kilograms (for this dosage test)
Body Surface Area

3. Begin by Converting to Kilograms
All MD orders will be ordered as a dose per kg
Convert the patient’s weight in lbs to kg by dividing the weight in lbs by 2.2
Example:
50 lbs divide by 2.2 =
Round to tenths place = 22.7 kg

4. Now you try! 1. Patients weight 48 lbs
How many kg does the patient weigh?
Patient weight 13.9 lbs

5. The MD order The MD order can be written in several ways:
In a daily total (dose not specified) after further calculation to be divided in equal doses
Ex: 30mg/kg/day administer orally equally divided in three doses or
Per dose
Ex: 15mg/kg administer orally twice daily

6. Lets Try it! Patients weight: 45 lbs
2. Give 30mg/kg/day administer orally equally divided into three doses
How many mg per dose? How much is the 24 hr drug total?
3. Give 30mg/kg administer orally in three divided doses

7. Is the dose safe?
All pediatric dosages have a recommended range in the drug guide
These ranges are typically based on a 24 hour total amount of a dosage in mg, mcg, gm, etc.
Remember how to convert mcg to mg, gram to mg etc.

8. Is the order safe?
A statement from the drug guide will be provided on the dosage assessment test
Ex: The drug guide states the recommended safe dosage is 3-5 mg/kg/day to be administered orally in 2 divided doses

9. Lets try it!
4. MD order Sporanox (itraconazole) 40 mg administer orally twice daily
Patients weight 47 lbs
Drug guide recommends 3-5mg/kg/day
administer orally in 2 divided doses.
Is the dose safe?

10. Supply Pediatric medication is typically supplied in liquid form
Some children can swallow pills or the medication may only come in tablet form
Most of the dosage assessment questions will consist of medication in liquid form, few questions will be in tablet form

11. Remember….
Supply is expressed as a dosage amount per a commonly used quantity
Example 250mg/5mL
100mg/mL
50mcg/mL
This is different from the total amount of drug dosage in the bottle

12. Calculate Liquid Medication
Dose desired
Dose on hand X quantity in mL
= volume to be administered

13. Lets try it! 5. MD order is to give 75 mg Supply is 250mg/5mL
Calculate the amount to administer

14. Read a label
Some dosage questions will require you to read a drug label
Mixing directions:Add 30 mL of water
Mix VigorouslyDiscard after 5 days
Zantac
(ranitidine)
Oral suspension25mg/5mL

15. Lets try it!
6. Using the medication label supplied above, how many milliliters should be administered per dose if the MD order is 100 mg administer orally once daily?

16. Ok, so how do you round? Look at it this way…
If the calculated answer is <1 mL then round to the hundredths place as this amount could be easily administered in a 1 mL syringe
Example: If the answer was 0.75 mL, where would you draw the solution to in this syringe?

17. What if the Answer is > 1 ml?
If the calculated dose is greater than 1 ml then you round to the tenths place
Example- if the dose was 2.75 ml, using a 3 ml syringe you would need to round to 2.8ml, as 2.75ml can not be precisely administered

18. For Example If the answer is 0.3762901
Round to 0.38mL…..don’t forget the zero in the ones place!
If the answer is
Round to 1.4 mL

19. NEVER……. Round to a whole number!!!!! If the answer is 1.89361
Round to 1.9 mL NOT 2 mL

20. So Remember:
< 1 mL rounds to 2 places to the right of the decimal place
>1 mL, kg, mg, mcg, anything else rounds to only 1 place to the right of the decimal place

21. Practice Rounding If you calculated the answer to be:
mg, round to:__________
mL , round to:_________
mL, round to:__________
, round to:__________
kg, round to:_______

22. Intravenous Nothing new here…. Volume in mL x drop factor = gtt/min
Time in min

23. You are Ready!!! Lets put it all together
8. The physician orders Kantrex (kanamycin) oral suspension 150 mg/kg/day administer orally in 2 divided doses.
Supply Kantrex 500mg/5mL.
Patients weight: 28 lbs
How many milliliters should be administered per dose?

24. 9. The physician orders Prostigmin (neostigmine bromide) 8 mg administer orally every 4 hrs
The drug guide recommended dosage is mg/kg/day to be administered in divided doses
Patients weight: 21 lbs
Is the physicians order safe?

25. Careful…some may have patients weight in kg already!
10. The physician orders Primacor (milrinone lactate) 50 mcg administer IM stat.
Supply: 0.2mg/mL
Patients weight: 12 kg.
How many milliliters should be administered per dose?

26. 11. The physician orders Sustiva (efavirenz) 20mg/kg administer orally twice daily
Supply: Sustiva 50 mg tablets
Patients weight: 11 lbs
How many tablets are to be administered per dose?

27. 12. The physician orders IV fluids as follows: Infuse 1000mL of 0
12. The physician orders IV fluids as follows: Infuse 1000mL of 0. 45% normal saline solution in 10 hours IV.
Calculate the flow rate when the drop factor is 10 drops per milliliters

28. You are ready to take the practice test
You are ready to take the practice test! Time yourself…you need to be able to complete in 30 minutes