Antimicrobials USMLE Step 1 Practice Question
A 62-year-old woman with a history of type 2 diabetes mellitus and a methicillin-resistant Staphylococcus aureus skin and soft tissue infection of the right lower extremity is prescribed vancomycin 1 g IV every 12 hours. Her baseline serum creatinine is 0.8 mg/dL, and her weight is 68 kg. On admission, her temperature is 38.2°C, blood pressure is 128/76 mmHg, heart rate is 92/min, and urinalysis is unremarkable. At day 5 of therapy, she reports decreased urine output, her serum creatinine has risen to 1.6 mg/dL, blood urea nitrogen is 28 mg/dL, and her vancomycin trough level is 24 μg/mL. Which of the following is the most appropriate next step?
Answer choices
- AAdd hydration and diuretics to promote vancomycin clearance
- BContinue current dosing; vancomycin-induced renal injury is always reversible
- CIncrease vancomycin dose to achieve trough levels >25 μg/mL
- DSwitch to gentamicin, which has less nephrotoxicity
- EReduce vancomycin dose and frequency due to declining renal functionCorrect answer
- FSwitch to linezolid for equivalent MRSA coverage without nephrotoxic potential
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.