Clark’s rule is based upon the weight of the child. To determine the proper dosage for children, divide child’s weight in pounds by 150 to get the correct fraction of adult dose. Example: For a 50 pound child give 50/150 (or 1/3) of the adult dose. Therefore, if the adult dose is 30 drops taken 3 times per day, the child’s dose will be 10 drops taken 3 times per day (not 30 drops taken 1 time per day!)
(Weight in pounds x (Adult dose)
(That's: Child's weight in pounds times adult dose divided by 150)
3. Young's Rule for Children from 1 year to 12 Years:
Young’s rule is based upon the age of the child, regardless of its weight. It is a “rule of the thumb” method for calculating the dose of medicine to be administered to a child. The child’s age divided by age plus 12 represents the fraction of the adult dose suitable for the child.
(Age in Years) x (Adult Dose)
Age + 12
(That's: Child's age in years times adult dose divided by child's age plus 12)