M O Yoshizumi1, A R Bhavsar, A Dessouki, A Kashani. 1. Department of Ophthalmology, The Jules Stein Eye Institute, Doris Stein Eye Research Center, UCLA School of Medicine, Los Angeles, California 90095-7000, USA.
Abstract
PURPOSE: To determine the retinotoxicity of repeated intravitreous injections of vancomycin, ceftazidime, and dexamethasone in rabbit eyes. METHODS: Twenty pigmented New Zealand rabbits were divided into two groups. In Group 1, the right eyes received repeated intravitreous injections with vancomycin 0.3 mg, ceftazidime 0.7 mg, and dexamethasone sodium phosphate 0.13 mg at three consecutive 48-hour intervals. Group 2 right eyes received three times higher dose of the same intravitreous drugs as used in Group 1, repeated at the same frequency. All left eyes served as control eyes. Retinotoxicity was monitored by slit-lamp biomicroscopy, indirect ophthalmoscopy, electroretinography, and light and electron microscopy. RESULTS: No evidence of retinotoxicity was found in Group 1 eyes. Photopic A-waves were significantly elevated, and 30- and 50-Hz flicker fusion amplitudes were significantly depressed in Group 2 eyes. No changes were found by clinical or histopathologic examination in the retinas of either group. CONCLUSIONS: Three repeated intravitreous injections at 48-hour intervals of a combination of vancomycin, ceftazidime, and dexamethasone in rabbit eyes at dosages that approximate drug concentrations recommended for human endophthalmitis were nontoxic. Similar injections at three times higher doses resulted in mild electroretinogram changes.
PURPOSE: To determine the retinotoxicity of repeated intravitreous injections of vancomycin, ceftazidime, and dexamethasone in rabbit eyes. METHODS: Twenty pigmented New Zealand rabbits were divided into two groups. In Group 1, the right eyes received repeated intravitreous injections with vancomycin 0.3 mg, ceftazidime 0.7 mg, and dexamethasone sodium phosphate 0.13 mg at three consecutive 48-hour intervals. Group 2 right eyes received three times higher dose of the same intravitreous drugs as used in Group 1, repeated at the same frequency. All left eyes served as control eyes. Retinotoxicity was monitored by slit-lamp biomicroscopy, indirect ophthalmoscopy, electroretinography, and light and electron microscopy. RESULTS: No evidence of retinotoxicity was found in Group 1 eyes. Photopic A-waves were significantly elevated, and 30- and 50-Hz flicker fusion amplitudes were significantly depressed in Group 2 eyes. No changes were found by clinical or histopathologic examination in the retinas of either group. CONCLUSIONS: Three repeated intravitreous injections at 48-hour intervals of a combination of vancomycin, ceftazidime, and dexamethasone in rabbit eyes at dosages that approximate drug concentrations recommended for humanendophthalmitis were nontoxic. Similar injections at three times higher doses resulted in mild electroretinogram changes.