Penetration of parenterally administered gentamicin into the cerebrospinal fluid in experimental meningitis.

The penetration of parenterally administered gentamicin into the CSF was examined in dogs. The experiments were carried out in three stages: (1) in healthy dogs, (2) in dogs with meningitis, and (3) during recovery from the acute inflammation. Gentamicin was found to penetrate poorly into the CSF, reaching mean peak levels of 0.7 mug/ml in healthy dogs. During the height of the meningeal inflammation the mean peak gentamicin level in the CSF was 0.9 mug/ml. The ratio of mean maximum CSF to mean maximum serum levels of gentamicin was 5.8% in healthy dogs, and 11.3% in dogs with meningitis. Thus, inflammation increases the penetration of parenterally administered gentamicin into the CSF, but therapeutically adequate levels for gram-negative bacillary meningitis are not achieved.