Pharmacokinetics>Tdm Interpretation Practice Test

A 64-year-old man (85 kg) is being treated for MRSA pneumonia with vancomycin 1,000 mg IV every 12 hours. A trough level obtained 30 minutes before the 4th dose is 7 mg/L. He is afebrile with improving respiratory status. Serum creatinine is 0.9 mg/dL (baseline 0.9), BUN 14 mg/dL, and estimated creatinine clearance is approximately 90 mL/min. No concomitant nephrotoxins are documented. The target for severe MRSA pneumonia is a vancomycin exposure consistent with an AUC/MIC of 400–600; if using trough-based monitoring, goal trough is typically 15–20 mg/L. The team asks for dosing guidance based on this level.

A 54-year-old man (85 kg) is being treated for MRSA pneumonia with vancomycin 1 g IV every 12 hours. He is on day 3 of therapy; the vancomycin trough, drawn 30 minutes before the 4th dose, is 9 mcg/mL. He remains febrile with a persistent productive cough, WBC 15,000. Renal labs today: SCr 0.9 mg/dL (baseline 0.9), BUN 14 mg/dL; estimated creatinine clearance is 95 mL/min. Concomitant medications include ceftriaxone and enoxaparin; no nephrotoxins or ototoxins are reported. Blood cultures are growing MRSA with an MIC to vancomycin of 1 mg/L. The infusion duration is 1 hour and doses have been administered on time. The pharmacist is asked to recommend dosing adjustments and monitoring.