Vancomycin is a glycopeptide antibiotic that is the first line antibiotics for the treatment of serious gram-positive infections involving methicillin-resistant Staphylococcus aureus (MRSA). Its therapeutic window is narrow, so there is a need to monitor serum vancomycin concentration in clinical practice, especially in the critically ill patients. So far, few studies have investigated the clinical outcomes of the dosage strategy that vancomycin dosage is administered and adjusted individually using PPK and Bayesian methods based on observed concentrations. The objective of this study is to investigate the effectiveness, safety and economics of the vancomycin individualized dosing service provided by pharmacists.

Vancomycin is a glycopeptide antibiotic that is the first line antibiotics for the treatment of serious gram-positive infections involving methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin use is associated with several adverse events, including nephrotoxicity and ototoxicity. Its therapeutic window is narrow, so there is a need to monitor serum vancomycin concentration in clinical practice, especially in the critically ill patients. Moreover, the Chinese vancomycin TDM guideline recommended that vancomycin dosage should be administered and adjusted individually based on population pharmacokinetic(PPK) and Bayesian methods. However, there is a gap between clinical practice and the guideline. So far, few studies have investigated the clinical outcomes of the dosage strategy that vancomycin dosage is administered and adjusted individually using PPK and Bayesian methods. Pharmacists could provide the vancomycin individualized dosing service by joining the ICU multidisciplinary team. The objective of this study is to investigate the effectiveness, safety and economics of the vancomycin individualized dosing service provided by pharmacists.

This is a single-center, ambispective cohort study. Patients from the retrospective and prospective cohort will be divided into 2 groups by exposure. The exposure is whether patients received pharmacists' consultation. Patients who meet the inclusion and exclusion criteria will be included in our registry. As a non-intervention study, these information as below will be collected: basic demographics, diagnosis, the initial dosage regimen and adjusted strategy of vancomycin, combined special treatment and outcomes.

Inclusion Criteria:

• Admitted to intensive care unit(ICU), Peking University Third Hospital since JAN 2010.
• Receiving vancomycin therapy for 72 hours or more.
• Aged ≥ 18 years.

Exclusion Criteria:

• Administration of vancomycin in non-intravenous access.
• Life expectancy of less than 24 hours.
• Pregnancy women.
• Presence of immunodeficiency.
• Presence of hematological disorder.
• Written informed consent not obtained in the prospective cohort.

The prospective cohort: all patients in this cohort will receive pharmacist consultation when prescribed vancomycin.

The retrospective cohort: patients in this cohort received usual care from JAN 2010 to MAR 2015; patients in this cohort received pharmacist consultation from APR 2016 to JUL 2016.