Gentamicin and tobramycin penetration into synovial fluid

Area of Science:

• Pharmacology
• Orthopedics
• Infectious Diseases

Background:

• Infectious arthritis requires effective antibiotic penetration to joint fluid.
• Aminoglycoside antibiotics like gentamicin and tobramycin are used to treat bacterial infections.

Purpose of the Study:

• To determine the penetration of gentamicin and tobramycin into synovial fluid.
• To assess the necessity of intra-articular aminoglycoside administration for infectious arthritis.

Main Methods:

• Studied 12 patients with nontraumatic joint effusions.
• Collected simultaneous serum and synovial fluid specimens.
• Assayed antibiotic levels after intramuscular or intravenous administration.

Main Results:

• Synovial fluid antibiotic levels were consistently over 50% of serum levels.
• In five patients, synovial fluid levels equaled or exceeded serum levels.
• Demonstrated significant aminoglycoside penetration into joint fluid.

Conclusions:

• Systemic administration of gentamicin and tobramycin achieves therapeutic concentrations in synovial fluid.
• Intra-articular injection of these antibiotics is not required for treating infectious arthritis.
• Supports the use of systemic aminoglycosides for joint infections.