Epileptogenic action of cephalosporins II. Epileptogenic action of certain cephalosporins administered intravenously into rats, and antiepileptic effect of certain anticonvulsants in cefazolin-induced seizure

Epileptogenic activities of certain cephalosporins administered intravenously into rats with stainless steel electrodes implanted into the frontal cortex, occipital cortex, hippocampus and amygdala were investigated. At doses of less than 200mg/kg, the cephalosporins did not induce any EEG or behavioral signs. At doses greater than 500 mg/kg, seizure effects were noticed in both EGGs and behavior in the decreasing order of ceftezole, cefotiam, cefazolin and cephaloridine. Especially at a dose of 1,000 mg/kg, seizure signs were noticed. Effects of diazepam, phenobarbital and phenytoin in preventing generalized seizures induced by intraventricular injection of 100 μg cefazolin were investigated. Intravenous administrations of diazepam and phenobarbital inhibited cefazolin-induced seizures markedly. The ID50(s) of inhibition of seizure patterns in EEG were 3.4 mg/kg and 30.5 mg/kg, respectively, and the ID50(s) of seizure behavior suppression were 4.7 mg/kg and 49 mg/kg respectively. However, phenytoin did not repress cefazolin-induced seizures even at 100 mg/kg (i.v.).