This document discusses dosage calculations for various medications using different pediatric formulas. It provides an example of calculating the oral dose of paracetamol for an 8-year-old child using Young's formula. Another example calculates the doses of isoniazid and rifampicin for a 6-year-old child using Dilling's formula. Finally, it presents a case study of a 60kg man with iron deficiency anemia and calculates the total iron requirement and duration of treatment with intramuscular iron dextran injections.

1. Dosage calculation
Dr Sumitha A MBBS,MD
Assistant professor

2. 1, Calculate the oral dose of Paracetamol for a child aged 8 years using
YOUNG’S formula.
Adult dose of paracetamol is 500mg/8th hourly = 1500 mg/day
Age X Adult dose = child dose
Age + 12
8 X 1500 = 600 mg/day (or) 200mg 8th hourly
8+12

3. 2, Calculate the pediatric dose of isoniazid and rifampicin for a 6
years old child by using dilling’s formula
Note: Adult dose of Isoniazid = 300mg OD
Adult dose of Rifampicin = 600mg OD
Child dose = Age x Adult dose
20
INH = 6 X 300 =90mg/day
20
Rifampicin = 6 x 600 = 180 mg/day
20

4. 3, 60 kg old man admitted with complaints of breathlessness
,lethargy and was extremely pale. On investigation he was found
to have iron deficiency anaemia with Hb – 9 gm.
Iron Dextran ( Complex of Ferric oxide with Low molecular weight
dextran which contains 50 mg of elemental iron /ml) is given in a
daily inj. Of 2ml
Questions:
Calculate the total iron to be given to the patient.
If the iron is to be given by IM calculate the duration of
treatment?

5. • Iron requirement (mg) =4.4 x body weight (kg) X Hb deficit
(g/dl)
Answer:
1. Iron requirement = 4.4 X60 X (14 -9)
= 1320 mg
Daily injection of 2ml
Each ml of iron Dextran contains 50 mg
and each day 2 ml is given ,
So, 100mg /day
1320 mg means 1320 = 13 days
100
Duration of treatment = 13 days