Abstracts

The precise mechanism of action of levetiracetam (LEV) is unknown; however the mechanism of action distinguishes LEV from most other antiepileptic drugs (AEDs). Anecdotal information suggests that LEV may be an especially useful adjunctive therapy in patients with Vagus Nerve Stimulation (VNS). This study examines the synergistic effects between LEV and VNS, by comparing seizure outcomes in patients with VNS on LEV against groups of patients with VNS on other medications., This was a retrospective review of outcome after VNS implantation using Engel[apos]s classification of seizure outcome following surgery. 132 patients were followed for at least one year following VNS implantation and data pertaining to age, gender, seizure type, AED use and seizure outcome were maintained in a database. Patients had VNS implanted for at least one year. Outcomes of 127 patients, both pediatric and adult patients with partial or generalized seizures were included. The following groups were assessed: patients on LEV and other drugs with VNS; patients on lamotrigine (LTG) and other drugs with VNS; patients on LEV and LTG with VNS; all other patients on other combinations of AEDs with VNS., Out of 127 patients, 17 patients were on LEV and other drugs, 42 patients on LTG and other drugs, 11 patients on a combination of LEV and LTG, and 57 patients were on other combinations of AEDs. Outcomes in terms of Engel[apos]s classification were assessed. No group had a statistically significant better outcome (patients in Engel Class I, II, and III, vs. class IV) as compared to the other groups (p=0.86). When patients on LEV were compared to all other groups (Engel Class I, II and III vs. class IV) there was no significant difference (p=0.30). When LEV was added on after VNS implantation, it was no more beneficial than the addition of other drugs (p= 0.10)., No statistically significant differences in seizure control were found when we compared LEV with other drugs in combination with VNS. Outcomes were about the same for all drug and VNS combinations. Further analysis using other outcome measures will be necessary to demonstrate difference between drugs. The possibility of a Type II error secondary to small numbers of patients in each group is recognized.,