After iv administration of 1000 mg of penicillin G to a patient with normal kidney function (CLT = 30 L/hr), the resulting AUC was 33.3 mg-hr/L. What is the expected penicillin G AUC if the same dose (1000 mg) is given to a patient with reduced kidney function (CLT = 10 L/hr) ? and what will be the dose that should be given to the patient with reduced kidney function (CLT =10 L/hr) to produce AUC of 33.3 mg-hr/L ?
Because penicillin G is excreted primarily through the kidney, reduced kidney function will result in reduction in the total body clearance of penicillin G.
The AUCs after administration of similar doses are inversely proportional to the total body clearance
The relationship between AUC, dose, and CLT is expressed as:
AUC =
1000mg
10 L/hr
= 100 mg-hr/L
Dose =
33.3 mg-hr/L x 10 L/hr
= 333 mg
