This study is looking at three seizure medicines. Patients with seizures are usually treated with phenytoin (Dilantin) or Fosphenytoin. These medicines can be given intravenously (IV)or by mouth. Another seizure medicine, levetiracetam (Keppra) can now be given this way also. This study will compare IV phenytoin (Dilantin) and IV fosphenytoin to levetiracetam (Keppra) in patients who have had a recent seizure. Only patients with a history of seizures can be involved. The patient must present to the emergency department within 4 hours of a seizure. The purpose of this study is to compare these three drugs, phenytoin (Dilantin), fosphenytoin, and levetiracetam (Keppra). The investigators are looking to see if these drugs can prevent another seizure in the next 24 hours. We are also looking for any possible side effects.