Central nervous system toxicity of intraventricularly administered gentamicin in adult rabbits

To determine whether daily intraventricular injection of gentamicin sulfate would cause neurologic or morphologic abnormalities of the central nervous system, adult male rabbits were given gentamicin sulfate, 2 mg/kg, intramuscularly twice a day plus saline, 0.2 ml (group 1), or gentamicin, 0.05 mg/kg (group 2), 0.25 mg/kg (group 3), or 0.5 mg/kg (group 4), given as the sulfate intraventricularly once a day. The majority of the animals in group 4 developed neurologic abnormalities which progressed to death in animals that were not euthanized; neuropathologic studies revealed chemical ventriculitis and meningitis that were associated with high levels of gentamicin in the cerebrospinal fluid and tissue of the central nervous system. Similar neurologic and morphologic changes were seen in most animals of group 3 but not in rabbits of groups 1 and 2. The ototoxicity and nephrotoxicity of gentamicin are well known; these data indicate that it may be toxic to the central nervous system as well.