Optimizing Vancomycin Therapy in Obese Critically Ill Patients: The Role of Therapeutic Drug Monitoring

In critical care, clinicians face challenges optimizing vancomycin dosing for obese patients. Addressing these challenges requires aligning dosing pharmacokinetics with therapeutic drug monitoring.

Obesity frequently increases vancomycin's apparent volume of distribution; effects on clearance are variable and largely mediated by renal function and augmented renal clearance in some patients. These pharmacokinetic differences introduce variability that warrants therapeutic drug monitoring—specifically AUC-guided approaches endorsed by the 2020 ASHP/IDSA/PIDS consensus—while obesity-focused nuances are explored in a recent review.

Because obesity can alter clearance, AUC-guided therapeutic drug monitoring (TDM)—commonly targeting an AUC24/MIC of 400–600—helps maintain therapeutic levels and avoid treatment failure or toxicity.

Observational data associate higher vancomycin exposures (e.g., higher troughs or AUCs) with increased acute kidney injury risk, reinforcing the need for therapeutic precision in obese patients. These insights are increasingly informing dosing strategies, emphasizing precision while the risk of nephrotoxicity is carefully managed.

These pharmacokinetic changes can influence clinical outcomes, including recovery time.

The study results point toward a new tier of monitoring—expanded use of Bayesian AUC estimation within EHR workflows—that refines dosing accuracy in obese patients and builds on AUC-guided TDM discussed earlier.

Bridging evidence to bedside requires embedding AUC-guided TDM into workflows (for example, pharmacy-led protocols). Despite technological advances, optimizing doses in obese patients still requires individualized, AUC-guided approaches rather than fixed BMI-based schemes.

Yet, trough-only strategies often miss AUC targets in obesity, underscoring the need to refine therapeutic drug monitoring for better outcomes. Emerging tools—such as Bayesian dosing software and EHR-integrated AUC calculators—can enhance patient safety through more precise monitoring.

For these individuals, achieving therapeutic levels can be complicated by augmented renal clearance or increased volume of distribution. With these insights, a next step could be integrating real-time AUC estimation modules into routine practice, extending the new tier of monitoring described above and further optimizing dosing strategies.

Key Takeaways:

• AUC-guided therapeutic drug monitoring is central to dosing adjustments in obese patients.
• Obesity increases vancomycin's volume of distribution and can alter clearance, affecting efficacy and safety.
• Individualized, AUC-guided dosing helps minimize nephrotoxicity risk while maintaining efficacy.