Effect of methylprednisolone on entry of ampicillin and gentamicin into cerebrospinal fluid in experimental pneumococcal and Escherichia coli meningitis.

The influence of methylprednisolone on the passage of ampicillin and gentamicin into and activity within cerebrospinal fluid was examined in two models of experimental meningitis. Steroid pretreatment reduced the concentrations of these drugs in purulent cerebrospinal fluid of rabbits with experimental pneumococcal and Escherichia coli meningitis (P less than 0.05). However, the resultant mean concentrations of these antibiotics in cerebrospinal fluid still exceeded the minimal bactericidal concentrations of the infecting organisms. The rate of bactericidal effect in vivo was unaffected by steroid therapy in each model. Methylprednisolone did not have deleterious effects on the course of treated experimental meningitis under these short-term (24-h) experiments.