PTCB Math. Clark’s Rule and Young’s Rule. (Pharmacy Technician Exam) -A long time ago I met my friend Clark that time he was young but when I told him that I’m going to take the PTC B exam he said remember these two formulas because you will find some questions on the test this is not a story but in this article I’m going to explain.
What are Clark’s and Young’s rules?
Then we will do practice questions
Clark’s rule relates the dose of a child’s weight as compared to an adult weight of 150 pounds.
Note: Clark’s rule uses weight and pounds never in kilograms adult dose times weight of child divided by 150 equals child’s dose.
Young’s rule uses age and easy to remember because it calculates the dose by the age of the patient’s adult dose times age of the child in years divided by age of the child plus 12 equals child’s dose.
Clark’s rule and the young rule will not always give identical answers so if you’re asked to calculate a child’s dose by young rule and if you use Clark’s rule instead or another method or if you forget both of them you will not get the correct answer on the exam please memorize these two formulas.
Let’s do some practice questions:
A little boy Kevin weighs 30 pounds and he is four years old another child named Lisa is also four years old but she has a weight of 40 pounds the adult dose of ibuprofen is 250 milligrams find the doses of both children with Young’s rule and Clark’s rule?
Let’s calculate the doses of Kevin’
adult dose times weight of child divided by 150 equals child’s dose adult dose equals 250 milligrams Kevin’s weight equals 30 pounds please make sure it is not in a kilogram 250 times 30 divided by 50 equals 250 times 0.2 zero which equals 50 milligrams.
for Kevin he is 4 years old now we are going to insert information in the form adult dose equals 250 milligrams adult dose times age of the child in years divided by age of the child plus 12 equals the child’s dose 250 times 4 divided by 4 plus 12 equals 1000 divided by 16 equals 62 point five milligrams.
The second child named Lisa:age four years old weight 40 pounds adult dose 250 pounds
Adult dose times age of the child in years divided by age of the child plus 12 equals child’s dose 250 times four divided by four plus 12 equals one thousand divided by 16 equals 62 point five milligrams this is the same answer as Kevin’s dose by using the young rule.
adult dose times the weight of the child divided by 150 equals child’s dose 250 times 40 divided by 150 equals 250 times point zero two six six sixty six point seven milligrams so if you compare for both children Kevin and Lisa they produce different dosages after using Clark’s rule but young rule produces the same answer .
let’s take a look at what kind of question you might see in the test a child is five years old and wait sixty pounds the adult dose of amoxicillin is 250 milligrams calculate the child dose by using both Clark’s rule and Young’s rule quiz time three questions how many milliliters are in one teaspoon the answer is five milliliters how many pints are in one quarts the answer is two pints how many pounds in one kilogram the answer is 2.2 pounds.