Question

SG is a 84 y/o male who has a SCr of 1.2mg/dL. He is 74" and weighs 210lbs. SG has been admitted for a CAP that has not resolved. The attending has prescribed cefepime 2g IV q 8H and clarithromycin 250mg PO q 12 H. Calculate CrCl for this patient and give dosing recommendations based on estimated renal function.

Answer 1

The Cockcroft-Gault equation can be used to calculate creatinine clearance (CrCl) and estimate renal function. For this patient, CrCl was calculated to be 38.81 ml/min. Dosing recommendations based on estimated renal function include adjusting the dosage interval for cefepime but no adjustment for clarithromycin.

Step-by-step explanation:

The Cockcroft-Gault equation is commonly used to calculate creatinine clearance (CrCl). The formula is as follows: CrCl = [(140 - age) x weight (kg)] / (72 x serum creatinine) for men. In this case, the patient is 84 years old and weighs 210 lbs (approx. 95.25 kg).

First, we need to convert the patient's weight from pounds to kilograms:

210 lbs ÷ 2.2046 = 95.25 kg

Next, we can calculate the CrCl using the given serum creatinine level of 1.2 mg/dL:

CrCl = [(140 - 84) x 95.25] / (72 x 1.2)

CrCl = 38.81 ml/min

Based on the estimated renal function, dosing recommendations can be made for cefepime and clarithromycin. Since cefepime is primarily excreted by the kidneys, a dosage adjustment based on CrCl is recommended. The usual dosing frequency for cefepime is every 8 hours, but for patients with a CrCl less than 60 ml/min, the dosing interval should be extended. For clarithromycin, no dosage adjustment is necessary as it is primarily eliminated by liver metabolism.