Concentrations of cefotaxime and the desacetyl metabolite in serum and CSF of patients with meningitis.

Thirty-two cases of meningitis (20 caused by Gram-positive or -negative cocci, 7 by Gram-negative bacilli or listeria, and 5 with aseptic meningitis) received cefotaxime, 2 g 8-hourly, in addition to routine therapy. The concentrations of cefotaxime and its desacetyl metabolite in serum and CSF were determined by a high pressure liquid chromotography. Mean concentration of cefotaxime in CSF ranged from 0.8 mg/l (aseptic meningitis), to 6.4 mg/l (Gram-negative and listeria meningitis), and from 0.5 to 5.4 mg/l for the metabolite. The concentrations of both cefotaxime and the derivative demonstrated a correlation with the degree of inflammation (i.e., cell count and protein concentration) and were higher at 3 h after an infusion of antibiotic than at one and two hours. The concentration showed no marked decline on day 10 when signs of inflammation had largely resolved. The concentrations of both the parent compound and the metabolite 3 h after the infusion suggest that, considering the activity and half life of both the dosing might be spaced at 6-8 h intervals.