The Rule of 6 for dosing amoxicillin, which we discussed in a previous post, is probably outdated since amoxicillin is typically dosed 80 to 90 mg/kg/day instead of 40 mg/kg/day for children (max 1000 mg per dose). So lets update this rule. For 90 mg/kg/day of amoxicillin, use the following calculation:
Weight in Pounds x 20 = mg dose of amoxicillin per dose
The other change is that this calculation is assuming 2x/day dosing (instead of 3x/day dosing). Let's go through an example. Assuming that you have a 10 pound child in your office, the calculation would look like this: 10 x 20 = 200. So this child would need 200 mg of amoxicillin 2x/day. Since amoxicillin comes in 400 mg per teaspoon, the child would need ½ teaspoon by mouth 2x/day.
The important thing to remember is that this calculation is PER DOSE (and NOT per day). Also, remember that this calculation only works for dosing amoxicillin 2x/day. Double check this calculation with your normal method of calculating the amoxicillin dose. I think you will find that they are pretty close!