Neurotoxicity and CSF level of three penicillins

The electrocortical activity and the antibiotic concentration in serum and CSF were investigated in rabbits after i.v. administration of benzylpenicillin, ampicillin and oxacillin. In contrast to ampicillin and oxacillin, benzylpenicillin induced a pronounced epileptogenic activity. The different epileptogenic activity of the three penicillins cannot be explained by the difference in the CSF level of these agents only. The intensity of the epileptogenic activity and the CSF level after benzylpenicillin administration were markedly influenced by the experimental procedure in that curarized animals exhibited both higher CSF levels and more intense seizure activities than non-curarized animals. Factors are discussed which may be responsible for the different neurotoxic potency of the three penicillins and for the dependence of the benzylpenicillin-induced seizure intensity on the experimental procedure.