Moxifloxacin dosing in post-bariatric surgery patients

Area of Science:

• Pharmacokinetics and Pharmacodynamics
• Antibiotic Dosing Strategies
• Obesity and Bariatric Surgery

Background:

• Increasing prevalence of obesity and bariatric surgeries necessitates updated drug dosing guidelines.
• Existing moxifloxacin dosing recommendations may not be adequate for post-bypass surgery patients.
• Population pharmacokinetic (PK) and pharmacodynamic (PD) analysis is required to assess drug efficacy in this population.

Purpose of the Study:

• To investigate whether adequate moxifloxacin concentrations are achieved in patients post-bariatric surgery.
• To evaluate the impact of lean body mass (LBM) on moxifloxacin pharmacokinetics.
• To assess the probability of target attainment for bacterial eradication and resistance suppression.

Main Methods:

• Utilized data from a moxifloxacin PK trial involving volunteers who underwent bariatric surgery.
• Employed a three-compartmental population PK model, with LBM as a predictor for moxifloxacin clearance.
• Conducted PK-PD simulations to evaluate target attainment probabilities for different scenarios.

Main Results:

• Moxifloxacin PK is best described by a three-compartmental model incorporating LBM.
• Probability of target attainment for bacterial eradication against Streptococcus pneumoniae is compromised in patients with higher LBM, especially at MICs ≥ 0.5 mg/L.
• Standard moxifloxacin dosing fails to achieve adequate levels for bacterial resistance suppression, even at MICs as low as 0.25 mg/L, particularly in patients with LBM ≥ 78 kg.

Conclusions:

• Standard moxifloxacin dosing is insufficient for optimal bacterial resistance suppression in post-bariatric surgery patients.
• A need for LBM-based, individualized moxifloxacin dosing in this population is emphasized.
• This study highlights the importance of adjusting antibiotic therapy based on patient-specific factors like LBM.