The purpose is to study the population pharmacokinetics, effectiveness and safety of antiepileptic drug (phenytoin, carbamazepine, lamotrigine, levetiracetam, parempanel, etc) in elderly patients and recommend optimized dosage regimens.

Inclusion Criteria:

1. Age ≥65 years old;
2. Diagnosed with epilepsy;
3. Using antiepileptic drugs for treatment;

Exclusion Criteria:

1. Patients who are expected to die within 48 hours;
2. Patients with allergy to antiepileptic drugs;
3. Patients receiving other investigational drugs;
4. Other factors that the researcher considers unsuitable for inclusion.

Elderly patients with epilepsy (≥65years).