Question

A 208 lb hospitalized patient received intermittent intravenous infusions of an antibiotic for a serious and life threatening infection from a burn wound. The patient received 3.3 mg/kg infused over 20 minutes administered every 6 hours. A blood samples was collected 45 minutes before the third infusion was started and the drug concentration was found to be 16.6 mcg/mL. Another blood sample was collected 45 minutes after the third infusion was completed and the drug concentration was found to be 54.2 mcg/mL. Assume steady state was achieved before these samples were collected. What dose should the patient receive in order to produce steady state minimum drug concentrations of S mcg/mL? Note: Please provide your answer in units of mg. Do not include the units in the answer you enter.)

Answer 1

208 lb approximately 94kg

blood volume = weight * average blood volume

here it will be 7076 ml

patient recieved 3.3 mg /kg infusion = 310.2 mg

before the third infusion he recieved 310.2mg +310.2 mg = 620.4 mg

blood concentration 16.6 mcg/ml

calculated value 620.4/7076 = .08767 mg/ml 87.67 mcg/ml

medicine expelled from blood 87.67 - 16.6 = 71.07 over 11 hours and 15 minutes

lossed per hour is 6.317 mcg

so for steady concentration of 5mcg/ml the drug should be given 11.317mcg/ml every one hour

for 6 hour infusion will be 67.902mcg /ml

dosage will be 480474 mcg

that equal to 480.47 mg

5.5mg per kg