The safety of intraocular linezolid in rabbits.

PURPOSE Intraocular injection of linezolid, a synthetic oxazolidinone antibiotic, was performed in rabbits to assess its safety as a possible treatment for endophthalmitis. METHODS Linezolid, 300 microg/0.1 mL, 200 microg/0.1 mL, or 100 microg/0.1 mL, was injected into the vitreous of the right eye of 12 rabbits. Balanced saline solution was injection into the left eye of each rabbit as a control. A standard electroretinogram (ERG) was obtained before injection and repeated 2 days and 1 and 4 weeks after injection. Intraocular pressure (IOP) was also measured after injection. After the experiment, the rabbits were euthanatized and the retinas were examined by light and electron microscopy. Differences between the two eyes in the ERGs, IOP, and histopathology were recorded. RESULTS There were no statistically significant differences in the electroretinograms obtained between the linezolid-injected eyes and the control eyes. Histopathology showed no changes in the study eyes compared with the control eyes. CONCLUSIONS Preservative-free linezolid is nontoxic to the retinas of rabbits when injected intravitreally, and this route can therefore be considered for the administration of linezolid in the treatment of endophthalmitis.