Topical and intravenous gentamicin in traumatically lacerated eyes

Intravenous or topical gentamicin may be the initial mode of treatment for lacerated or ruptured eyes by emergency room physicians while awaiting ophthalmic consultation and surgical repair. The purpose of this study was to determine the possibility of having retinotoxic intravitreal gentamicin concentrations in experimentally lacerated rabbit eyes treated with either intravenous or topical gentamicin separately or in combination with each other. Nontoxic concentrations of gentamicin were found in the vitreous bodies by all routes of drug administration. After 3 h intravitreal concentrations of gentamicin were: 0.20-0.30 microgram/ml when treated intravenously, 0-2.9 micrograms/ml when treated topically, and 0.20-0.51 microgram/ml when treated both intravenously and topically. While the upper range of topically applied gentamicin concentrations (2.9 micrograms/ml) is therapeutic for some pathogens, the wide range of intravitreal concentrations (0-2.9 micrograms/ml) achieved does not indicate that topically applied gentamicin with or without intravenously administered gentamicin can reliably achieve therapeutic concentrations.