Antimicrobial And Opioid Stewardship Practice Test

A 76-year-old male (68 kg) with chronic kidney disease is admitted for pyelonephritis and is receiving gentamicin 5 mg/kg IV every 24 hours plus ceftriaxone 1 g IV every 24 hours. Home meds: furosemide 40 mg PO daily and amlodipine 5 mg PO daily. Labs: SCr 2.2 mg/dL (baseline 1.8 mg/dL), estimated creatinine clearance 25 mL/min; AST/ALT 20/18 units/L; WBC 14.5 $x10^3$/mcL. Allergy: anaphylaxis to penicillin. Recent hospitalization 1 month ago for UTI. Which monitoring parameter is most critical for this patient?

A 29-year-old female (55 kg) is seen in urgent care for dysuria and urinary frequency for 2 days. She was started yesterday on levofloxacin 750 mg PO daily for 5 days. Current meds: ethinyl estradiol/levonorgestrel 1 tablet PO daily. Labs: SCr 0.7 mg/dL; WBC 8.0 $x10^3$/mcL; temperature 37.2°C. Urine culture now shows Escherichia coli susceptible to nitrofurantoin and trimethoprim/sulfamethoxazole; resistant to fluoroquinolones. Allergy: none. No recent hospitalizations. Which intervention is most appropriate for this patient's antimicrobial therapy?