ABSTRACT
OBJECTIVES: Vancomycin weight-based dosing regimens often fail to achieve therapeutic trough serum concentration in children ≤12 years of age and rigorous studies evaluating efficacy and safety of body surface area (BSA)-based dosing regimens have not been performed. We compared vancomycin trough serum concentrations in pediatric patients receiving a weight- or BSA-based dosing regimen. METHODS: This was a single-center, retrospective study evaluating pediatric patients, ages 1 to 12 years, who received vancomycin from September 2012 to October 2015. Patients received a minimum of 3 consecutive doses at the same scheduled interval within a dosing regimen prior to a measured vancomycin serum trough concentration. The primary outcome was percentage of initial vancomycin trough concentrations ≥10 mg/L. The secondary outcomes were percentage of supratherapeutic, therapeutic, and subtherapeutic vancomycin serum concentration for all patients, including a subset of overweight and obese patients, and number of nephrotoxic occurrences. RESULTS: BSA-based dosing regimens resulted in 50% of the initial vancomycin trough concentrations ≥ 10 mg/L compared with 17% for the weight-based dosing regimens (p < 0.0001). No statistically significant differences were noted between the 2 dosing regimens for supratherapeutic, therapeutic, or subtherapeutic trough concentrations for all patients, and for the subset of overweight and obese patients. Nephrotoxic occurrences were noted in 7% of the weight-based dosing regimens compared with none in the BSA-based dosing regimens. CONCLUSIONS: A BSA-based vancomycin dosing regimen resulted in significantly more initial vancomycin trough concentrations ≥10 mg/L and trended towards higher initial vancomycin trough concentrations without observable nephrotoxicity.
ABSTRACT
OBJECTIVES: Determine the effect of exogenous antithrombin III administration on low molecular weight heparin anti-Xa levels in the context of enoxaparin dosing in infants. METHODS: A retrospective chart review of infants receiving concomitant antithrombin III and enoxaparin. The primary objective of this study was to determine the median change in anti-Xa level with antithrombin III supplementation. Secondary objectives were to analyze the median change in antithrombin III levels after administration of exogenous antithrombin III, the dosing of antithrombin III, and the dose of enoxaparin throughout therapy. For a safety analysis, any bleeding events were recorded. RESULTS: The study included 17 patients who received a total of 33 doses of antithrombin III. The median change in anti-Xa levels in infants receiving exogenous antithrombin III was 0.2 units/mL (p < 0.001). The median dose of antithrombin III was 50 units/kg and was administered when patients were receiving a median enoxaparin dose of 1.71 mg/kg. The median increase in antithrombin III levels was 16.5% (p < 0.001). CONCLUSIONS: These results demonstrated that administration of exogenous antithrombin III to infants who were being treated with enoxaparin results in a significant increase in anti-Xa levels. At this time, there is insufficient evidence to recommend routine administration of antithrombin III to infants on enoxaparin. However, antithrombin III supplementation could be considered a potential option for patients who are unable to adequately achieve therapeutic anti-Xa levels with enoxaparin alone.
