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The penetration of gentamicin into the vitreous humor in man
Abstract:
Twenty-two patients received gentamicin intramuscularly or subconjunctivally 35-220 min prior to undergoing ocular surgery. There were no detectable gentamicin levels in the vitreous humor of patients who received the drug systemically. Of the patients who received gentamicin subconjunctivally, three quarters had no detectable gentamicin levels, only three of these patients had therapeutic concentrations in their vitreous humor. These results confirm kinetic drug studies performed in animals in which low or absent vitreal gentamicin levels were observed following systemic and subconjunctival administrations. It is suggested that intravitreal injection of aminoglycosides is required in the treatment of bacterial endophthalmitis.
Insights
Systemic or subconjunctival gentamicin administration rarely achieved therapeutic levels in the vitreous humor for ocular surgery patients. Intravitreal injection is likely necessary for treating bacterial endophthalmitis effectively.
Area of Science:
- Ophthalmology
- Pharmacokinetics
- Infectious Diseases
Background:
- Bacterial endophthalmitis is a serious ocular infection requiring effective antibiotic treatment.
- Gentamicin, an aminoglycoside antibiotic, is commonly used but its penetration into the eye is critical.
Purpose of the Study:
- To evaluate gentamicin concentrations in the vitreous humor following systemic and subconjunctival administration prior to ocular surgery.
- To determine the efficacy of current administration routes for achieving therapeutic intraocular levels of gentamicin.
Main Methods:
- Twenty-two patients undergoing ocular surgery received gentamicin intramuscularly or subconjunctivally.
- Vitreous humor samples were analyzed for gentamicin levels at the time of surgery.
- Drug concentrations were correlated with administration route and timing.
Main Results:
- No detectable gentamicin levels were found in the vitreous humor after systemic administration.
- Only 25% of patients receiving subconjunctival gentamicin achieved therapeutic vitreous concentrations.
- Results align with prior animal kinetic studies showing poor intraocular penetration.
Conclusions:
- Systemic and subconjunctival gentamicin administration are inadequate for achieving therapeutic vitreous concentrations.
- Intravitreal injection of aminoglycosides is recommended for effective treatment of bacterial endophthalmitis.