Gentamicin pharmacokinetics in adults with bacterial endocarditis

Area of Science:

• Pharmacokinetics
• Internal Medicine
• Infectious Diseases

Background:

• Gentamicin is a crucial antibiotic for treating bacterial endocarditis.
• Understanding gentamicin's pharmacokinetic variability is essential for optimizing patient outcomes.
• Previous studies have not fully elucidated gentamicin's behavior in endocarditis patients.

Purpose of the Study:

• To investigate the pharmacokinetics of gentamicin in adult patients diagnosed with bacterial endocarditis.
• To identify factors influencing gentamicin's distribution volume (V), clearance (CL), elimination rate constant (k), and half-life (t1/2).

Main Methods:

• Retrospective analysis of 64 adult endocarditis patients treated between May 1990 and May 1993.
• Serum gentamicin concentrations and serum creatinine (SCr) levels were analyzed.
• Pharmacokinetic parameters (V, CL, k, t1/2) were calculated using a dedicated program.

Main Results:

• Mean gentamicin half-life (t1/2) was 4.7 hours and mean distribution volume (V) was 0.29 L/kg.
• Serum creatinine (SCr) and V explained 66% of the variation in gentamicin's half-life (t1/2).
• No significant difference in V was found between patients with normal and abnormal SCr levels. Men exhibited lower elimination rate constants (k) than women. Younger patients (<60 years) had lower V and CL compared to older patients.

Conclusions:

• Adult patients with endocarditis may exhibit an expanded gentamicin distribution volume (V).
• Distribution volume (V) and clearance (CL) are primary determinants of gentamicin's half-life (t1/2) variability in this population.
• These findings highlight the need for individualized gentamicin dosing strategies in endocarditis patients.