How much Tylenol or Motrin can I give my child?
Q)
Dr. Gwenn:
I have an 11month old son who weighs 20lbs. How much Tylenol or Motrin can I give him?
Thanks!
AC, Massachusetts
A)
Dear AC:
Great question. Figuring out over the counter medications dosing can be confusing, especially since kid's weights are constantly changing and dosing is based on weight. You'll notice that dosing guidelines on the medications include ranges by weight and age. These are ok in a pinch but are not very accurate because they cover a wide range of weights and are not precise for your child.
The best way to dose your child with medication is by weight, which is what we do when we give you advice for all medications. You can do this for pounds or kilograms depending on what you are comfortable with.
Here are the formulas we use for both Tylenol(acemaminophen) and Motrin/Advil(Ibuprofen):
Tylenol: 15mg/kg/dose or 7mg/pound/dose every 4 hours.
Dose = 15xweight(kg) or 7xweight(lb)
Motrin: 10mg/kg/dose or 4.5mg/pound/dose every 6hours.
Dose = 10xweighg(kg) or 4.5xweight(lb)
So, based on your son's current weight of 20lbs, here's how'd you'd figure out his current dose:
Tylenol: 20 x 7 = 140mg of tylenol. Tylenol comes in 80mg droppers or 160mg teaspoon. So, to not over dose him, you'd give him the closest reasonable dose which is about 120mg or 1 1/2 droppers of infant Tylenol or 3/4 Teaspoon of Children's Tylenol. When in doubt, go a bit less than a bit more if you are between doses.
Motrin: 20 x 4.5 - 90mg. Motrin comes 50 mg in the Infant dropper or 100 mg per teaspoon in the Children's elixir. So, just shy of 1 teaspoon or just about 2 droppers of the 50mg line would be your son's dose of Motrin.
Dr. Sears has some handy charts that spell out various weights and doses per the type of medication and the medication form, infant or children's elixir, that are based off these equations and useful when you don't feel like reaching for your calculator. Here are the links:
Dr. Sears Tylenol Page
Dr. Sears Motrin Page
Infant’s weights change frequently until they become toddlers. It is a good idea to know your infant’s weight every month or so. Once your infant becomes a toddler, the weight will only change every few months. You can figure out your infant’s weight on any home scale by weighing yourself holding your infant and subtracting your weight. Home scales are very inaccurate for very teeny weights, such as 20ish pounds and less.
Finally, be sure you really need to give either medication before you give it. Your pediatrician can guide you best on that front if you are all uncertain.
Cheers,
Dr. Gwenn
