Antimicrobial dosing in obese patients

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Obesity Medicine

Background:

• Weight-based dosing is common for some drugs but not most antimicrobials.
• Obesity presents unique pharmacokinetic challenges, yet its impact on antimicrobial efficacy is largely unknown.
• Current empirical methods for antimicrobial dosing in obesity lack robust validation.

Purpose of the Study:

• To review the English-language literature on antimicrobial pharmacokinetics and dosing in obesity.
• To evaluate the impact of obesity on antimicrobial drug disposition and clinical outcomes.
• To identify evidence-based approaches for adjusting antimicrobial dosages in obese individuals.

Main Methods:

• Systematic literature review of English-language studies on antimicrobial pharmacokinetics and obesity.
• Analysis of pharmacokinetic consequences of obesity relevant to drug dosing.
• Evaluation of existing empirical formulas and clinical data for weight-based antimicrobial dosing.

Main Results:

• The precise effect of obesity on the pharmacokinetics and efficacy of most antimicrobials remains undetermined.
• An empirical approach uses the Devine formula with a dosing weight correction factor (DWCF) for hydrophilic antibiotics, but lacks confirmation for beta-lactams.
• Clinical data suggest DWCFs of approximately 0.40 for aminoglycosides and 0.45 for quinolones.

Conclusions:

• Weight-related antimicrobial dosage adjustments in obesity require further research and validation.
• Specific weight correction factors may be applicable to certain antimicrobial classes like aminoglycosides and quinolones.
• Therapeutic drug monitoring, including serum concentrations, is crucial for antimicrobials with a narrow therapeutic index in obese patients.