Penetration of ciprofloxacin into the cerebrospinal fluid of patients with uninflamed meninges.

Nine patients with external ventriculostomy and suffering from hydrocephalus, due to non-inflammatory central nervous system diseases, were given ciprofloxacin (200 mg twice daily iv). Ciprofloxacin concentrations in serum and CSF were measured by HPLC. Single-dose pharmacokinetics were determined in three patients, and 60 and 600 min post-dose levels after repeated administration in six patients. CSF concentrations were maximal 60-120 min after the end of the infusion. The CSF elimination half-life was 260-430 min compared with 145-170 in serum. Post-dose levels at 60 min ranged from 0.042 to 0.223 mg/l (median = 0.110). Repeated administration did not lead to substantial increases in serum and CSF concentrations. With respect to MIC90 values reported for bacteria involved in CNS infections, the CSF concentrations of ciprofloxacin obtained under our experimental conditions would be considered subtherapeutic. Thus ciprofloxacin therapy of CNS infections may be inadequate when only minor impairment of the blood-CSF barrier exists.