Children's dosage guidelines

The following are general guidelines for children. Dosages may need to be adjusted as required by the severity and duration of the condition, as well as the child’s weight, lifestyle and diet. Practitioners are advised to use clinical judgment when calculating a suitable dose for child patients.

Please note that not all products are suitable for every age group given.

Young's Rule for child dosing



0-1 y.o.

1/8 of the normal adult dose 

1-2 y.o. 

1/4 of the normal adult dose

2-5 y.o.

1/3 of the normal adult dose

5-12 y.o. 

1/2 of the normal adult dose 

12+ y.o. 

Adult dose (unless the child is particularly small) 


Clark's Rule for child dosing

Divide the child's weight (in kg) by 70* and multiply this by the normal adult dose; i.e. if the child weighs 35kg: 35/70 = 0.5; the dosage is half of the recommended adult dose. Please note that this method is only suitable if the child’s weight is normal for their age.

*Recommended adult doses are based on 70kg adults.