Vancomycin levels after intravitreal injection: Effects of inflammation and surgery

H. E. Aguilar, T. A. Meredith, A. El-Massry, A. Shaarawy, M. Kincaid, J. Dick, D. J. Ritchie, R. M. Reichley, M. K. Neisman

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: Vancomycin hydrochloride for intraocular injection is the drug of choice for the treatment of suspected gram-positive endophthalmitis. To study its intraocular pharmacokinetics, we injected vancomycin into the vitreous cavity of phakic, aphakic, and aphakic-vitrectomized rabbit eyes and determined its rate of clearance. Inflamed eyes were compared to control eyes in each group. Methods: Three groups of eyes were prepared. The eyes in Group 1 were phakic, the eyes in Group 2 had the lens removed, and the eyes in Group 3 had both the lens and central vitreous removed. Each group was subdivided into a control group and a group made inflamed by injection of heat-killed Staphylococcus epidermidis. Vancomycin hydrochloride 1 mg in 0.1 cc of diluent was injected into the midvitreous cavity and samples obtained at 2 or 3, 8, 24, and 48 hours after injection. Vancomycin concentrations were measured and clearance rates were calculated for each of the groups. Results: Vancomycin was cleared substantially faster from aphakic- vitrectomized eyes (half-life 9.0 hours) and aphakic eyes (half-life 8.9 hours) than phakic eyes (half-life 25.1 hours). Inflammation increased the rate of elimination of vancomycin only in the aphakic group. Conclusions: Clearance of vancomycin from the phakic eye is prolonged compared to that of beta-lactam antibiotics, an important pharmacokinetic advantage in treating endophthalmitis. Its clearance from aphakic-vitrectomized eyes is dramatically faster than from phakic eyes and is similar to that of other antimicrobial agents.

Original languageEnglish (US)
Pages (from-to)428-432
Number of pages5
JournalRetina
Volume15
Issue number5
DOIs
StatePublished - Jan 1 1995

Keywords

  • endophthalmitis
  • pharmacokinetics
  • vancomycin
  • vitreous surgery

ASJC Scopus subject areas

  • Ophthalmology

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