Efficacy and Safety of a Vancomycin (VAN) Dosing Protocol Developed for Morbidly Obese (MO) Patients

BACKGROUND: An optional VAN loading dose (LD) of 25–30 mg/kg (total body weight), followed by maintenance dose (MD) of 15–20 mg/kg intravenously (IV) Q8–12H is recommended for patients with normal renal function. Studies suggest MO patients may require lower mg/kg doses to achieve therapeutic trough concentrations (TTCs). Our institutional VAN dosing protocol for MO patients (BMI ≥ 40 kg/m(2)) was revised in 2015 to recommend: LD 25–30 mg/kg (max 3000 mg), MD 12.5–15 mg/kg (max 2000 mg) IV Q8–12H. We evaluated initial TTC attainment, clinical and safety endpoints post protocol revision. METHODS: MO adult patients who received IV VAN between June 1, 2012–May 31, 2013 (pre-protocol revision) and August 1, 2015–July 31, 2016 (post-protocol revision) were included. Perioperative VAN, one-time doses, pregnancy, cystic fibrosis, hemodialysis and patients receiving VAN prior to admission were excluded. RESULTS: A total of 615 patients were screened, with 200 included for analysis (100 per group). Baseline demographics and VAN dosing are shown in Table 1. Initial TCs were drawn for 86 patients in the pre-revision group, and for 69 patients in the post-revision group. Initial VAN TCs are displayed in Table 2. Duration of VAN therapy was significantly shorter post-revision (5 days vs. 2 days, p ≤ 0.01). Mortality (14% vs. 10%, P = 0.38) and hospital length of stay (8.5 days vs. 7 days, p=0.09) were comparable between groups. There was no difference in the incidence of VAN-associated nephrotoxicity (16% vs. 10%, P = 0.20). CONCLUSION: The revised VAN dosing protocol for MO patients improved initial TTC attainment and decreased incidence of subtherapeutic TCs compared with current standard of care recommendations with no difference in clinical or safety outcomes. DISCLOSURES: All authors: No reported disclosures.