Effect of Time of Mannitol Administration on the Antibiotic Concentrations in Cerebrospinal Fluid

Objective The effect of time of mannitol administration on the antibiotic concentrations in Cerebrospinal fluid (CSF) was examined to provide data for rational use of the two drugs. Methods Twelve neurosurgical postoperative patients were studied on self-control basis. From the first day after operation, the mannitol was administered 1 h or 30 min after antibiotic(ceftriaxone) adminitration, or 30 min, 1 h before the antibiotic adminitration, or two drugs were used at the same time. The concentrations of the antibiotic in CSF was measured 1 h after administration of antibiotic by reversed-phase high performance liquid chromatography. Results The ceftriaxone concentration was highest when given 30 min after the administration of antibiotic as compared with the concentrations of the antibiotic given at the other time points (P0.01 for all). Conclusion The blood-brain barrier (BBB) is open at the highest level 30 min after the infusion of antibiotic, and the ceftriaxone can pass through the BBB most easily, which is helpful for the prevention of CNS infection.