Erratum to: 39th ESCP European symposium on clinical pharmacy & 13th SFPC congress: clinical pharmacy at the front line of innovations. 21–23 October 2010, Lyon, France

Erratum to: Int J Clin Pharm (2011) 33:285–467 DOI 10.1007/s11096-011-9481-6

Abstracts

ERRATUM—This abstract should have been included in the abstract set.

CPK-5 Vancomycin dose adjustment in obese patients

A. Estefanell ^1,*, G. Riu ¹, D. Soy ¹, C. Codina ¹, J. Ribas ¹

¹Hospital Pharmacy, HOSPITAL CLÍNIC, BARCELONA, Spain

Introduction Multiple pharmacokinetic (PK) studies have demonstrated that total body weight is the best method to dose vancomycin. However, clinicians usually prescribe the standard dose of antibiotic (1 g/12 h), independently of weight.

The aim of this study is to obtain the percentage of obese patients treated with vancomycin at the standard doses of 1 g/12 h with suboptimal serum concentrations.

Materials & Methods Study conducted at 800-bed University General Hospital.

Observational study from July 2009 to May 2010 in (1) obese patients (BMI ≥ 30 kg/m²), (2) with creatinine clearance (Clcr) >50 ml/min and (3) monitored for vancomycin concentrations after the third dose of antibiotic (dosage: 1 g/12 h).

Individual PK parameters were estimated by assuming a bicompartmental PK model and Bayesian forecasting (PKS^® Abbot Software). Afterwards, daily dose was adjusted to achieve a minimum vancomycin concentration at steady state (C ^SS_min ) of 7–15 mg/l and a maximum vancomycin concentration at steady state (C ^SS_max ) of 20–40 mg/l, in case of bacteraemia, or C ^SS_min of 15–20 mg/l and C ^SS_max of 30–40 mg/l, in case of meningitis, pneumonia, osteomyelitis, wound infection or abscesses.

Data reviewed were: (1) demographics; (2) vancomycin serum concentrations withdraw 30 min before dose (C ^SS_min ) and 2 h after ending antibiotic infusion (C ^SS_max ) and (3) individual PK parameters.

Results Ninety-one patients were recruited. Only 37 out of 91 patients fulfilled the inclusion criteria. Demographic data: 54% men (20 patients), age (mean ± SD) 62.8 ± 12.0 years, weight 95.9 ± 17.2 kg, BMI 35.2 ± 5.2 kg/m², Clcr 70.1 ± 17.1 ml/min. Observed vancomycin serum concentrations after 3 doses of 1 g/12 h: mean C ^SS_min 7.0 ± 3.3 mg/l, mean C ^SS_max 16.4 ± 5.7 mg/l. Individual drug PK parameters (mean ± SD): steady-state volume of distribution 59.6 ± 13.4 l, total clearance 6.1 ± 2.0 l/h.

Dose increase was needed in 27 patients (73.0%): 1,000 mg/6 h was set in 1 patient, 1,250 mg/8 h in 2 patients, 1,000 mg/8 h in 15 patients and 1,250 mg/12 h in 9 patients. Dose decrease to 750 mg/12 h was needed in 3 patients (8.1%). Six patients (16.2%) remained with the initial regimen, and in 1 case (2.7%), vancomycin was switched to linezolid because of Staphylococcus aureus methicillin-resistant pneumonia.

Discussion, Conclusion Results indicate that a high percentage of the patients included were underdosed (75.7%). Monitoring serum concentrations of antibiotic is necessary to adjust vancomycin dose to achieve therapeutic concentrations at the target infection site.

Bibliographic references

• 1. Alvarez F, Olaechea P, Grau S, Marín M, Domínguez A, Martínez-Lanao J, Soy D et al. Recomendaciones para la monitorización de antibióticos en pacientes críticos ingresados en UCI. Farm Hosp. 2008;32(2):113–23.

• 2. Hall R, Payne K, Bain A, Rahman A, Nguyen S, Eaton S, et al. Multicenter Evaluation of Vancomycin Dosing: Emphasis on Obesity. The American Journal of Medicine (2008) 121: 515–18.

Keywords Dose adjustment, Obese patients, Vancomycin