Vancomycin pharmacokinetics in critically ill patients.

Area of Science:

• Pharmacology
• Nephrology
• Critical Care Medicine

Background:

• Vancomycin is a critical antibiotic for treating severe infections.
• Accurate dosing is essential, especially in critically ill patients with altered pharmacokinetics.
• Renal function significantly impacts drug elimination and requires careful monitoring.

Purpose of the Study:

• To evaluate vancomycin serum levels and pharmacokinetics in severely ill patients.
• To assess the influence of renal function on vancomycin elimination.
• To identify factors contributing to inter-patient variability in vancomycin clearance.

Main Methods:

• Measured peak and trough vancomycin serum levels in 37 severely ill patients.
• Utilized the Moellering nomogram for dosing adjustments.
• Studied vancomycin pharmacokinetics, including plasma elimination half-life, in 10 additional patients.
• Correlated vancomycin clearance with creatinine clearance.

Main Results:

• Observed higher-than-expected peak (61.2 +/- 23 mg/l) and trough (22.6 +/- 16.5 mg/l) vancomycin serum concentrations.
• Calculated a mean elimination half-life of 7.8 +/- 2.8 h in patients with creatinine clearance > 1 ml/min/kg.
• Found a prolonged mean elimination half-life of 18.3 +/- 10.2 h in patients with creatinine clearance <= 1 ml/min/kg.
• Demonstrated a correlation between vancomycin clearance and creatinine clearance.
• Noted significant inter-patient variability in vancomycin clearance.

Conclusions:

• Vancomycin dosing requires careful consideration in critically ill patients due to high serum levels.
• Reduced renal function markedly increases vancomycin elimination half-life.
• Potential tubular damage in severe sepsis may contribute to decreased vancomycin elimination.