Antimicrobial agents and the central nervous system.

There is an ever-expanding number of antimicrobial agents available for the clinician to use to combat infections. We review the majority of such agents that are currently available relative to their theoretical or proven efficacy in the treatment of CNS infections. Due to the unique ability of the CNS to exclude many agents delivered via the blood stream, easily administered and efficacious therapy remains a problem. Based on the pharmacokinetics of anti-infective drugs and their antimicrobial spectrum, at present a penicillin derivative or chloramphenicol should be used whenever possible because parenteral therapy will usually achieve the desired results. In many neurosurgery-associated infections, intrathecal or intraventricular antibiotics may be required to supplement parenteral treatment and/or surgical intervention. Some of the more promising agents (such as rifampin, trimethoprim-sulfamethoxazole, and metronidazole) await further clinical trials to establish their place in the therapeutic armamentarium. Careful, randomized, prospective studies of prophylactic antibiotics must be performed in the neurosurgical setting. A group of tables are included that summarize the expected spinal fluid levels, the sensitivities of organisms commonly causing neurosurgical infections, doses of drugs given intrathecally or intraventricularly, and recommended regimens for certain infections.