Efficacy of zonisamide—our experience commentary on Yamauchi

Dr. Yamauchi has pointed out that those patients receiving polytherapy did not do as well as those receiving zonisamide monotherapy. He backed up his observations with blood levels of zonisamide for all the groups. I believe that his observations suggest that the zonisamide dose should be higher, unless the side effects become limiting. As this was a retrospective study, detailed analyses were not carried out on each patient. For those patients who did not develop side effects, the zon-isamide dose should have been increased. There were some patients whose dose was increased, but not sufficiently. In hindsight, we could have increased the dose even more. Patients with Lennox-Gastaut syndrome have several different seizure types. How were the different types evaluated? We did not go into that much detail in classifying the improvement rate according to seizure type within a syndrome. Audience member We are all intrigued with your experience in treating patients with idiopathic spike-and-wave disease. We have found valproate to be useful in some cases, but it has some unacceptable side effects. Do any of your patients who have failed therapy with valproate respond to zonisamide? In our experience zonisamide is not often effective for atypical absence seizures. Audience member Have you had good results with zonisamide compared to valproate in patients with tonic-clonic seizures and spike-and-wave disease? It is difficult to answer that question, because generally if the patient responds to the first drug we will not try to switch them to another. We have yet to carry out a comparison trial. In my experience, until a drug has been used for more than 10 years it is regarded as a new drug, and it generally is not the first choice for monotherapy. Now zonisamide has been used in Japan for more than 10 years and we are beginning to act as if it is no longer new.