Dosage calculations

Question

The patient has an order for gentamicin (Garamycin) 4 mg/kg/day divided into 3 doses. The patient weighs 188 lb. The medication available is gentamicin 4 mg/mL. How many mg should be administered for each dose? ___ mg (If needed, round to the nearest whole number.)

Answer 1

To calculate the gentamicin dose per dose:

Convert the patient's weight from pounds (lb) to kilograms (kg):

188 lb ÷ 2.2 lb/kg = 85.45 kg (rounded to two decimal places)

Calculate the total daily dose of gentamicin:

4 mg/kg/day x 85.45 kg = 341.8 mg/day (rounded to one decimal place)

Divide the total daily dose by the number of doses per day:

341.8 mg/day ÷ 3 doses/day = 113.93 mg/dose

Round the dose to the nearest whole number:

The calculated dose of gentamicin per dose is 114 mg (rounded to the nearest whole number).

Therefore, the patient should receive 114 mg of gentamicin for each of the three doses per day.

Answer 2

first you need to convert the patients weight from pounds to kg:

188 lbs X 1 kg/2.205 lbs = 85.2754 kg

next, in one day we know that the patient needs 4mg per kg of body weight:

4mg/kg X 85.2754 kg= 341.1016mg/day

now we divide this into 3 doses

341.1016 mg/day X (1 day/3 doses) =113.7 mg/dose