Fosphenytoin is an effective neuroprotectant against ischemia-induced damage. In fosphenytoin (30 mg/kg, i.m.)-treated rat 5 min after ischemia episode, hippocampal CA1 pyramidal neurons remain at near control level (13.90 +/- 0.92), however, GFAP staining iss not significantly changed. In fosphenytoin (84 mg/kg)-treated rat, the relative bioavailability of fosphenytoin is 83%. In fully kindled female Wistar rats, fosphenytoin dose-dependently increases the focal seizure (afterdischarge) threshold. Seizure severity and duration at threshold are reduced only after the highest does of fosphenytoin tested (84 mg/kg).