Abstracts

Rationale: The ketogenic diet (KD) is a high fat, adequate protein and low carbohydrate diet typically used for intractable epilepsy. The vast majority of patients also receive concomitant anticonvulsant medications. Little is known, however, about which medications work well in conjunction with the KD. The aim of this study was to determine if synergy exists between the KD and commonly used anticonvulsant medications. Methods: A retrospective study was performed of 217 patients started on the ketogenic diet from 2000-2007 at our institution. Patients who discontinued the diet prior to three months (n=20), or for whom no follow up data were available (n=9) were excluded from analysis. Efficacy data at 3 and 6 months for patients on the KD and the identified 6 most commonly used concomitant anticonvulsants (levetiracetam, lamotrigine, phenobarbital, topiramate, valproate, and zonisamide) were analyzed and compared. Results: A total of 188 patients (99 male) were included in the analysis. In the subgroup of patients in whom no medication changes were made over the first 3 months of the KD (n=124), those taking zonisamide were more likely have a >50% seizure reduction (90% vs 70%, p=0.040) and those receiving phenobarbital were less likely (47% vs. 77%, p= 0.014). In those with Lennox Gastaut syndrome or mixed seizure types specifically (n=58), those receiving either zonisamide (100% vs. 57%, p=0.005) or valproate (78% vs. 53%, p=0.050) were more likely to have a >50% response whereas patients receiving phenobarbital were again less likely (29% vs 71%, p=0.036). Conclusions: In this cohort, children receiving zonisamide overall and valproate (for Lennox Gastaut or multiple seizure types specifically) were more likely to respond to the ketogenic diet. Those receiving the ketogenic diet and phenobarbital together did less well.