Cerebrospinal fluid penetration of mezlocillin.

The passage of 6-[(R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenyl-acetamido)-penicillanic acid sodium salt (mezlocillin, Baypen), into the CSF was studied in 9 patients with symptoms of acute meningitis, presumed to be of viral origin. The antibiotic was given as a single 5 g dose i.v. over 30 min. The CSF/serum concentration ratio of mezlocillin showed a variation from 0 to 10.7%. The antibiotic could be effective in the treatment of bacterial meningitis caused by ampicillin-resistant strains of Haemophilus influenzae and by most Enterobacteriaceae, provided these results will be confirmed by a study now in progress. In one patient suffering from meningococcal meningitis this concentration ratio varied between 72% (day 3) and 54% (day 12).