How is the dosage of medication for children calculated?

All medicines are poisonous, so the dosage must be accurate, especially for children. After purchasing the medicine, it will usually be shown on the box how much you should take. If it does not show that, you have to calculate it yourself. You can calculate how much you should take based on your child's weight, or you can convert it based on the adult dosage or calculate it based on body surface area.

(I) Weight calculation method

(1) Calculate weight based on age: 2-4 kg for newborns

6 months 4-7 (kg)

1 year old 7-10 (kg)

Weight for children over 1 year old is calculated as follows: actual age × 2 + 8 = weight (kg)

(II) Dosage calculated based on body weight

Calculate your body weight, multiply it by the daily dosage of a certain medicine per kilogram of body weight, and then take it in divided doses.

Dose conversion by age (converted to adult dose):

From birth to 1 month old, 1/15-1/8 of the adult amount

1/10-1/6 of the adult dose for 2-6 months

1/5-1/4 of the adult dose for 7-11 months

1/4 of the adult dose for 1 to 2 years old

1/3 of the adult dose for 3-4 years old

2/5 of the adult dose for 5-6 years old

1/2 of the adult dose for 7 to 9 years old

2/3 of the adult dose for 10-14 years old

If the child is too fat or too thin, the weight conversion method can be used: child dose = adult dose/50×child weight.

(III) Conversion according to adult dose

Age Dose (Adult=1)

Birth-1 month 1/18-1/14

1 month - 6 months 1/14/1/7

6 months-1 year 1/7-1/5

1 year old - 2 years old 1/5 - 1/4

2 years old - 4 years old 1/4 - 1/3

4-6 years old 1/3-2/5

6-9 years old 2/5-1/2

9-14 years old 1/2-2/3

14-18 years old 3/4

(IV) Calculation of dose based on body surface area

Calculation formula: Pediatric dosage = adult dosage × child's body surface area / 1.7

(1.7 is the body surface area of ​​an adult weighing 70 kg, in m2.)

Calculation of body surface area:

When the child weighs less than 30 kg: Child's body surface area = weight × 0.035 + 0.1

For children weighing more than 30 kg, the body surface area is calculated according to the following method: for every 5 kg increase in weight, the body surface area increases by 0.1 square meters on the basis of 1.1. For example, if your body weight is 35kg, your body surface area is 1.1 + 0.1 = 1.2m2; 40kg is 1.3m2. And so on, but when the weight is 60kg, it is 1.6m2; when the weight is 70kg, it is 1.7m2. This method is more reasonable and is suitable not only for children but also for adults.