Dosage in Children

Dosages are generally based on body-weight (in kilograms) or the following age ranges:

• First month (neonate)
• Up to 1 year (infant)
• 1-5 years (children)
• 6-12 years (School age)

Age	Ideal Body weight (kg)	Height (cm)	Body surface area (m2)	Precentage of adult dose
Newborn	3.4	50	0.23	12.5
1 Month	4.2	55	0.26	14.5
3 Months	5.6	59	0.32	18
6 Months	7.7	67	0.40	22
1 year	10	76	0.47	25
3 years	14	94	0.62	33
5 years	18	108	0.73	40
7 years	23	120	0.88	50
12 years	37	148	1.25	75
Adult Male	68	173	1.8	100
Adult Female	56	163	1.6	100

Body-surface area (BSA) estimates are more accurate for calculation of pediatric doses than body-weight since many physical phenomena are more closely related to body-surface area. The average body-surface area of a 70-kilogram human is about 1.8 m2. Thus, to calculate the dose for a child the following formula may be used:

Approximate dose for child Patient= [surface area of pateint (m²) divided by 1.8] x adult dose.

Referance: British National Formulary