title: Elevated Vancomycin Trough Concentration: Increased Efficacy and/or Toxicity?
abstract: Vancomycin susceptibility of methicillin-resistant Staphylococcus aureus has been changed over time and its average minimum inhibitory concentration increased from 1.5 to 1.75 mg/L.A recently published guideline by the American Society of Health Pharmacist recommended a daily dose of 15-20 mg/Kg every 8 to 12 hours of vancomycin to achieve a trough concentration between 15-20 mg/L for treatment of severe infections. Medical records of 69 patients from infectious ward of Imam Khomeini hospital, with suspected or confirmed gram-positive infection who had at least one trough level of vancomycin, were evaluated regarding vancomycin therapeutic goal; efficacy and renal safety. Most of patients (60.6%) with severe infections did not achieve the recommended vancomycin trough level during treatment course. Time to normalization of the signs and symptoms of infection did not correlate with the patients' serum vancomycin trough levels. At the end of treatment course, there was no significant correlation between patients' creatinine clearance and vancomycin trough levels (P=0.32). However, patients'cratinine clearance showed a negatively significant correlation with trough level of vancomycin (P=0.01). Vancomycin induced nephrotoxicity was detected in 4.3% of the patients. These data showed that vancomycin trough level may not necessarily assure treatment success, and also it would not essentially predict the risk of vancomycin induced nephrotoxicity. However, more well designed studies with larger sample size needed for better clinical and practical judgment.
authors.affiliation: Department of Clinical Pharmacy, Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Elyasi
authors.affiliation: Department of Clinical Pharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Khalili
authors.affiliation: Department of Clinical Pharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Simin
authors.initials: S
authors.lastname: Dashti-Khavidaki
authors.affiliation: Department of Infectious Diseases, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Emadi-Koochak
authors.affiliation: Department of Clinical Pharmacy, Faculty of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Amirhooshang
authors.initials: A
authors.lastname: Mohammadpour
authors.affiliation: Department of Pathology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Abdollahi
keywords: Efficacy; Toxicity; Trough level; Vancomycin