pediatric nursing

1. PEDIATRIC
DRUG DOSE CALCULATIONS

2. INTRODUCTION
• The medicine doses are calculated based on child’s weight.
• It makes the doses much more precise in children
• Its important that the child’s most recent weight in
kilograms is entered into the record, so that the drug
dosage calculations are accurate.

3. DEFINITION
It is an appropriate administration of desired strength and
quantity of drugs to infants and neonates to improve their
health condition

4. 1. Dose: amount of drug taken by patient for intended
therapeutic effect
2. Dosage regimen: schedule of taking drug dose
3. Most drug doses are measured in units of weight (e.g., 500
mg).
4. Many drug doses are general, not patient specific.
5. Desired dose: amount to be administered at one time
6. Amount to administer: volume containing desired dose
7. Dosage ordered: total amount of ordered drug and its
frequency of administration

5. DOSAGE CALCULATION TERMS
 Dosage unit: volume of medication containing quantity of drug
as listed on drug label
 Dose on hand: amount of drug in dosage unit
 Dosage strength: dose on hand per dosage unit

6. PURPOSES
• Prevent drug complication
• Improve child’s general health condition
• Appropriate administration of desired drug

7. RIGHTS OF DRUG ADMINISTRATION
• Right drug
• Right child
• Right route
• Right dose
• Right frequency / time
• Right assessment
• Right approach
• Right education
• Right evaluation
• Right documentation
• Right to refuse
• Right principle of care
• Right prescription
• Right nurse/ clinician

10. COMMON FORMULA ‘S
FOR
DRUG CALCULATIONS

11. Upto 2 years of Age

12. Example:
Calculate the child dose for a 2 year old baby, where the adult dose of the medicine is
500 mg.
Given:
Age of child(months) = 24 (2 years baby)
Average adult dose = 500 mg
TO find ; child’s dose
Solution:
Using with the formula we get
Child’s dose = age of child (months) x average adult dose
150
𝟐𝟒
𝟏𝟓𝟎
×500 mg = 80 mg

14.  Example
A 10 year old girl was prescribed paracetamol(500 mg as average adult dose).
Calculate the child dose
Given:
Age of child = 10 years, Avg adult dose: 500 mg
To find; child dose
Solution:
child dose = Age of child x Average adult dose
Age of child + 12
𝟏𝟎
𝟏𝟎+𝟏𝟐
x 500 mg
𝟏𝟎
𝟐𝟐
𝐱 500 mg = (0.45 ) x 500 mg = 225 mg

16. CLARK’S RULE USE WEIGHT IN POUNDS, NEVER IN KILOGRAMS

17.  Example
Consider a 10 year old girl/ 60 lb (pounds) prescribed Amoxicillin 500 mg adult
dose. Calculate child dose
Given :
Weight of the child = 60 lbs , Adult dose = 500 mg
To find;
child dose
Solution:
Child dose = weight of child (lbs) x Adult dose
Avg adult weight (150 lbs)
𝟔𝟎
𝟏𝟓𝟎
x 500 mg = 200 mg

18. DRUG CALCULATION WHEN DOSE IS KNOWN TO FIND
AMOUNT IN MILLILITERS
For vial;
Amount =
𝑤ℎ𝑎𝑡 𝑤𝑒 𝑤𝑎𝑛𝑡
𝑤ℎ𝑎𝑡 𝒘𝒆 ℎ𝑎𝑣𝑒
x No.of divisions in syringe

19. Example
A 5 year old pre-schooler was prescribed 20 mg of Pantoprazole.
Calculate the amount to be administered from the vial.
Solution:
What we want = 20 mg
What we have = 40 mg
Dilution = 40 mg Pantoprazole in 5 ml of sterile water
Calculate the amount to be taken in ml to administer to child
𝟐𝟎
𝟒𝟎
x 5
= 0.5 x 5
= 2.5 ml

20. For syrup;
A 3 year old toddler is prescribed 200 mg of paracetamol syrup.
Calculate the dose on ML
What we want = 200 mg
What we have = 250 mg ( available in bottle)
Dilution = 250 mg in 5 ml
=
𝟐𝟎𝟎
𝟐𝟓𝟎
x 5
= 0.8 x 5
= 4 ml

21. WHEN AMOUNT IS PRESCRIBED AND DOSE TO
BE FOUND OUT
Dose per 1 ml =
𝐷𝑜𝑠𝑒 𝑎𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒 𝑖𝑛 𝑏𝑜𝑡𝑡𝑙𝑒
𝑅𝑎𝑡𝑒 𝑜𝑓 𝑑𝑖𝑙𝑢𝑡𝑖𝑜𝑛
x dose to be administered

22. Example
A 3 year old toddler is prescribed to be administered 2 ml of
Paracetamol syrup.
Calculate the dose in milligrams.
Solution:
What we want = 2 ml
What we have =m 5 ml contains 250 mg in a bottle
Dose =
𝟐𝟓𝟎
𝟓
x 2
= 50 mg x 2
= 100 mg

23.  CALCULATING PEDIATRIC IV SOLUTIONS
No. of drops/ min = Amount of fluid in (ml) x drop factor to be given in 24 Hrs
No. Of hours x 60
Drop factor = 60 (micro drip) and 15 (macro drip)
Example
Normal saline (500 ml ) in 4 Hours
500 x 60
4 x 60
= 125 drops / min