Therapeutic drug monitoring of vancomycin

Area of Science:

• Pharmacology
• Infectious Diseases
• Clinical Pharmacy

Background:

• Vancomycin, a critical antibiotic for Gram-positive infections like MRSA, has known risks of nephrotoxicity and ototoxicity.
• Monitoring vancomycin serum concentrations is crucial for safe and effective treatment.
• In Mexico, routine vancomycin level monitoring occurs, but its use in dose adjustment is often empirical.

Purpose of the Study:

• To evaluate the appropriateness of vancomycin dosing in sepsis patients based on established therapeutic intervals.
• To identify the proportion of patients receiving sub-therapeutic or toxic vancomycin doses.
• To propose alternative dosing strategies if current regimens are inadequate.

Main Methods:

• Retrospective analysis of 295 vancomycin peak and trough levels in adult sepsis patients (18-65 years).
• Established the relationship between administered vancomycin dose and measured serum concentrations.
• Utilized a single compartment model incorporating creatinine clearance to characterize the study population's pharmacokinetics.

Main Results:

• Only 44% of trough concentrations (C(trough)) and 47% of peak concentrations (C(peak)) fell within the therapeutic range.
• A significant proportion of patients received vancomycin doses resulting in ineffective or toxic drug levels.
• A pharmacokinetic model was developed to describe vancomycin behavior in relation to creatinine clearance.

Conclusions:

• Current vancomycin dosing practices for sepsis patients in this cohort are frequently inadequate, leading to suboptimal therapeutic outcomes.
• There is a need for more precise vancomycin dosing strategies to optimize efficacy and minimize toxicity.
• Pharmacokinetic modeling can aid in understanding and improving vancomycin dose adjustments.