Antimicrobials USMLE Step 1 Practice Question

A 34-year-old woman with HIV infection (CD4 count 45 cells/μL) on antiretroviral therapy presents with a 3-day history of fever (39.2°C), severe headache, and neck stiffness. Cerebrospinal fluid analysis reveals elevated protein (145 mg/dL), low glucose (28 mg/dL, serum glucose 110 mg/dL), and positive cryptococcal antigen. Amphotericin B deoxycholate is initiated at standard dosing with aggressive intravenous hydration (normal saline 1 L every 8 hours). After 7 days of therapy, the patient develops flank pain, oliguria, and worsening renal function (serum creatinine increased from 0.9 to 3.8 mg/dL, BUN 92 mg/dL). Urinalysis shows muddy brown casts but no proteinuria or hematuria. Which of the following interventions would most effectively reduce the risk of further amphotericin B-associated nephrotoxicity?