How To Calculate The Pediatric Drug Dose?

Example:

Calculate the dose of Amoxicillin suspension in mLs for a patient weighing 20 pounds. The dose required is 50 mg/kg/day divided three times daily and the suspension comes in a concentration of 250 mg / 5 ml

Step 1: If the patient weight is in pounds convert it to kilograms

22 pounds × 0.45359237 = 9.979 kilograms

Step 2: Calculate the daily dose in milligrams

50 × 9.979 = 498.951 mg per day

Step 3: Check if the calculated daily dose exceeds the maximum daily dose

498.951 mg per day does not exceed the maximum daily dose

Step 4: Divide the daily dose by the frequency

498.951 ÷ 3 = 166.317 mg per dose repeated three times daily

Step 5: Convert the milligrams dose to milliliters volume

166.317 × 5 ÷ 250 = 3.3263 ml per dose repeated three times daily

Step 6 : Rounding the volume

The final answer is
Amoxicillin 250 mg / 5 ml Suspension
Give 3.3 ml three times daily