Initial dose of vancomycin in adult patients at a major tertiary care hospital in Saudi Arabia: A retrospective observational study

Background: Therapeutic drug monitoring is commonly performed to confirm the safe and effective use of the vancomycin; however, the facility for it is not available in many hospitals. Many clinicians use conventional fixed dose of 1000 mg every 12 h irrespective of the body weight. Aim: The aim of the study was to assess the appropriateness of vancomycin initial dose in adult patients with normal renal function. Setting and Design: This was a retrospective observational study involving medical records of patients treated with intravenous vancomycin during January 1, 2016–December 30, 2016, at a major tertiary care hospital in southern region of Saudi Arabia. Materials and Methods: The study was conducted based on electronic medical records of the patients who received intravenous vancomycin, aged ≥ 18 years, weighing more than 50 kg, and with normal renal functions during the period of the study. Chi-square tests were used for categorical variables. Multivariable logistic regressions were computed to examine the relationships between the explanatory variables and the appropriateness of vancomycin dose. Results: The study evaluated records of 456 adult patients, of which 63.8% were male. As per vancomycin dose received, 229 patients received suboptimal dosing of vancomycin when the dose was recalculated using actual body weight. The majority of the prescriptions of junior residents (68.5%) were using an optimal initial dose of vancomycin as compared to 43.6% of the senior residents or 48% of the consultants. Conclusions: A significant number of patients were receiving suboptimal initial dose of vancomycin. Junior residents were more meticulous with the initial vancomycin dosing.