A 52-year-old woman with metastatic breast cancer on active chemotherapy presents to the hospital with fever (39.2°C), productive cough, and dyspnea for 3 days. She is immunocompromised with an absolute neutrophil count of 480/μL. Vital signs: HR 112 bpm, RR 22/min, BP 128/76 mmHg, SpO2 94% on room air. Chest X-ray shows bilateral interstitial infiltrates. She has acute kidney injury with serum creatinine 1.8 mg/dL (baseline 0.9 mg/dL) and BUN 32 mg/dL. Empiric therapy with piperacillin-tazobactam and tobramycin was initiated 24 hours ago. A tobramycin trough level drawn just before the third dose is 8 mcg/mL (therapeutic target <1 mcg/mL). Sputum culture and blood cultures are pending. Which of the following is the most appropriate next step in management?

1. A)Decrease tobramycin dose and extend the dosing interval based on the patient's estimated glomerular filtration rateGABARITO
2. B)Increase the tobramycin dose to 7 mg/kg to achieve therapeutic peak levels of 15-30 mcg/mL
3. C)Continue the current tobramycin regimen; elevated trough levels will normalize once acute kidney injury resolves
4. D)Discontinue tobramycin and add ciprofloxacin for similar gram-negative coverage with renal dosing
5. E)Maintain piperacillin-tazobactam monotherapy and discontinue all aminoglycosides due to nephrotoxicity risk