Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders>>>>>Drug Dosing in Renal Failure
Question 5#

A 42-year-old male with history of positive human immunodeficiency virus status with poor compliance to antiretroviral therapy presents to the ICU with altered mental status and severe hypotension, requiring aggressive intravenous fluid resuscitation, vasopressor therapy, and endotracheal intubation with sedation. He has recently been in a skilled nursing facility and was lost to follow-up on discharge. Cultures are drawn, and he is placed on broad-spectrum antimicrobial therapy as further workup is being performed. His basic labs show that he has acute kidney injury with creatinine 2.3 mg/dL with estimated glomerular filtration rate (eGFR) 38 mL/min/1.73 m² .

Which of the following is FALSE regarding antibiotic treatment in this patient?

A. Checking a trough level for vancomycin is a useful tool to help determine an appropriate dose for the individual patient
B. As many antimicrobial medications are renally excreted, a dose reduction should be considered based on the eGFR to avoid overdose
C. When patients are placed on continuous renal replacement therapy (CRRP), antimicrobials tend to reach supratherapeutic levels because of further decrease in the clearance of these medications
D. There are two main ways to adjust the total dosage of antimicrobials given to the patient—changing the dosing interval and the dose of medication given each time

Correct Answer is C

Comment:

Correct Answer: C

Renal dysfunction is a commonly associated with sepsis, especially in the setting of septic shock with hemodynamic instability. As many antimicrobial medications are renally excreted, dose reductions may be warranted. Vancomycin is one of the few drugs for which trough level is available to help guide dose adjustments. Appropriate antimicrobial dosing is critical to treat the underlying infection in sepsis while avoiding the negative side effects from supratherapeutic levels. For example, an excessive dose of imipenem/cilastatin may cause seizures.

When patients are placed on CRRT, drugs are also removed as well. As a result, patients placed on CRRT may have subtherapeutic levels of their antimicrobial therapy. Therefore, it would be important to consider increasing the dosing of antimicrobials that are more readily cleared by CRRT.

References:

1. http://med.stanford.edu/bugsanddrugs/guidebook/_jcr_content/main/panel05-25.pdf.
2. https://www.nebraskamed.com/sites/default/files/documents/forproviders/asp/Renal-Dose-Adjustment-Guidelines-forAntimicrobial.pdf.
3. Heintz BH, Matzke GR, Dager WE. Antimicrobial dosing concepts and recommendations for critically ill adult patients receiving continuous renal replacement therapy or intermittent hemodialysis. Pharmacotherapy. 2009;29(5):562-577.