Population Pharmacokinetics and Dosing Simulations of Ampicillin and Sulbactam in Hospitalised Adult Patients

BACKGROUND

The pharmacokinetic variability of ampicillin-sulbactam in adults has not been extensively described, particularly in patients with a reduced renal function (i.e., < 60 mL/min).

OBJECTIVE

This study investigated the population pharmacokinetics of ampicillin and sulbactam in patients with a wide range of renal functions and sought to define dosing approaches that have a high likelihood for optimising drug exposure.

METHODS

Serial blood samples were collected from 16 adult patients receiving intravenous ampicillin-sulbactam in general wards. Total ampicillin and sulbactam concentrations were measured by chromatographic assay and pharmacokinetic parameters were estimated using Pmetrics^®. Monte Carlo simulations were used to evaluate the probability of target attainment (PTA) of free ampicillin and sulbactam concentrations exceeding the minimum inhibitory concentration (MIC) for 60% and 100% of the dosing interval. Fractional target attainment (FTA) was calculated against MIC distributions of common hospital pathogens. A threshold of ≥ 90% and ≥ 95% was used to define both optimal PTA and FTA, respectively.

RESULTS

The median (range) age, weight, and serum creatinine of the study population was 68 (40-82) years, 62 (40-82) kg, and 1.4 (0.6-6.4) mg/dL, respectively. The pharmacokinetics of ampicillin and sulbactam were best described by a two-compartment model with serum creatinine most closely associated with clearance for both drugs. The estimated ampicillin and sulbactam clearances were 5.58 L/h and 4.79 L/h, respectively, while the volumes of distribution were 12.6 L and 15.36 L, respectively. Approved dosing regimens of ampicillin-sulbactam were sufficient against MICs ≤ 8 and ≤ 4 mg/L, respectively. A 4-h infusion enabled optimal PTA at higher MICs. For both dosing targets, optimal FTAs were obtained against Streptococcus pneumoniae.

CONCLUSION

Optimal FTAs were obtained against the susceptible MIC distributions of Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii. Applying a 4-h infusion will enhance PTA and FTA, particularly at higher MICs.

Indonesian healthcare providers' perceptions and attitude on antimicrobial resistance, prescription and stewardship programs

Background: A successful antimicrobial stewardship program (ASP) is sustained through improving antimicrobial prescribing by changing prescribing behavior. This requires a better understanding of hospital stakeholders' views regarding antimicrobial resistance (AMR), antimicrobial use and participation in ASP activities. Objectives: Identify perceptions and attitudes among physicians and pharmacists in a public hospital toward AMR, prescription and ASP. Methods: A questionnaire consisting of 45 items was distributed to physicians and pharmacists in a 320-bed public hospital. All responses were formatted into the Likert scale. Results: A total of 78 respondents (73% response rate) completed the questionnaire. The majority of the respondents perceived AMR within hospital as less of a severe problem, and factors outside hospital were considered to be greater contributors to AMR. In addition, interprofessional conflict was identified as a serious concern in relation to implementing ASP. Conclusion: This finding indicates the need to address existing perceptions and attitudes toward ASP activities that may hamper its successful implementation in Indonesia.