Question

The physician ordered Kefzol (cefazolin sodium) IM 25 mg/kg/day in three equal doses every 8 hours for a child who weighs 50 pounds. Convert pounds to kilograms and then calculate the prescribed dosage. ______ mg every _____ hours

Answer 1

Our basis is the value 25 mg/kg·day. The mg at the numerator is for the dosage, the kg at the denominator is for the weight of the patient and the day is for the time of dosage. First convert the weight from pounds to kg knowing that there are 2.2 lbs in every 1 kg.

Weight = 50 lbs* 1 kg/2.2 lbs = 22.73 kg

The solution for prescribed dosage is:

25 mg/kg·day * 22.73 kg = 568.25 mg/day
Since there are 24 hours in day, then the dosage should be administered 3 times because 24/8 = 3. It is mentioned that there should be 3 equal doses. Therefore, the dosage should be:

Dosage = 568.25/3 = 189.42 mg every 8 hours