Abstract
The number of patients with epilepsy receiving chronic hemodialysis is expected to increase, as the population continues to age in Japan. We report a patient with frontal lobe epilepsy receiving chronic hemodialysis and formerly treated with valproate and phenytoin, in whom post-dialysis seizures were controlled by additional zonisamide. The patient was a 50-year-old woman. Intermittent hemodialysis was initiated when she was 43 years of age due to aggravation of interstitial nephritis. At 49 years of age, she began to experience convulsive seizures. Symptomatic localization-related epilepsy caused by old cerebral infarction in right frontal lobe was diagnosed, and treatment with valproate 1,400mg/day and phenytoin 175mg/day was started. However, seizures continued to occur during post-dialysis period. She was referred to our hospital. Slight increases of the valproate and phenytoin dosages achieved seizure control. She was seizure-free for 3 years, until 53 years of age, when post-dialysis seizure reappeared. Addition of zonisamide 500mg/day was effective in stopping her seizures. Mean elimination rates of the antiepileptic drugs by hemodialysis were 46% for valproate, 33% for phenytoin, and 18% for zonisamide. During treatment of patients with epilepsy receiving chronic hemodialysis, monitoring pre- and post-dialysis blood concentrations and adjusting the doses of antiepileptic drugs are essential to achieve optimal pharmacotherapy.
