1. Instructions
Know These:
1 milliliter (mL)=1 cubic centimeter (cc) 1 teaspoon (tsp)= 5 milliliters (mL)
1000 milliliters (mL)= 1 Liter (L) 3 teaspoon (tsp)= 1 tablespoon (Tbsp)
1000 micrograms (mcg)= 1 milligram (mg) 2 tablespoons (Tbsp)= 1 ounce (oz)
1000 Grams (G)= 1 Kilogram (Kg) 30 milliliters (mL)= 1 ounce (oz)
1000 milligrams (mg)= 1 Gram (G) 2.2 pounds (lb)= 1 Kilogram (Kg)
Calculating dosages
1 Consult a pediatric drug reference guide for information on dosage (see References for a source
providing a list of guides). Note whether the drug is one where dosage is calculated based on weight,
BSA or age.
2 Determine the patient's age, weight in kilograms (children) or grams (infants), and height in
centimeters. If your scale only provides weight in pounds, convert to kilograms by dividing the weight in
pounds by 2.2. For children under 1, convert to grams by dividing the kilogram value by 1,000. If your
scale only provides height in inches, convert to centimeters by multiplying the height in inches by 2.54.
3 If the drug is one where dosage is calculated by weight, multiply the patient's weight by the dosage
listed in the drug guide. For example, for a child weighing 10 kg taking a drug with a recommended
dosage of 20 mg/kg/day, the daily dosage would be 10 kg x 20 mg/kg/day = 200 mg/day.
4 If the drug is one where dosage is calculated by BSA, multiply the patient's height by his or her
weight. Divide the result by 3,600. Take the square root of the result. Finally, multiply the result by the
dosage listed in the drug guide. For example, for a child whose weight is 20 kg and whose height is 100
cm taking a medication with a recommended dosage of 2 mg/m2/day, the daily dosage would be: 20 x
100 = 2,000; 2,000/3,600 = 0.55; √0.55 = 0.74; 0.74 m2 x 2 mg/m2/day = 1.48 mg/day.
5 If the drug is one for which dosage is calculated by age, multiply the patient's age by the dosage
listed in the drug guide. Age is measured in years, months or days, as determined by the recommended
dosage. For example, for a 6-year-old child taking a medication with a recommended dosage of 1
mg/years of age/day, the daily dosage would be 6 mg/day.
2. 6 Divide the daily dosage by the number of doses to be given per day. For example, if a medication
with a recommended dosage of 4 mg/day is to be given twice per day, the dose for each administration
of the drug would be 2 mg.
7 Divide the dose by its concentration to calculate the dose in milliliters. Pediatric drugs are usually
dispensed at a predetermined concentration. For example, for a drug administered in 2-mg doses and
prepared in a 1-mg/mL concentration, each dose would be 1 mL.
