Abstracts

Lamotrigine (LTG) has been shown to be effective in treating the depressive phase of bipolar disorder in randomized clinical trials. Additional studies have shown positive mood effects of LTG in patients with epilepsy. It is not known if baseline levels of mood disturbance will result in different degrees of seizure control with adjunctive and monotherapy LTG. This analysis evaluated the efficacy of LTG in patients with varying degrees of baseline mood disturbance.
Data for this analysis were collected as part of a large outpatient study. Patients with partial epilepsy age 16 years and older entered the study either because of poor seizure control or unacceptable side effects on their current antiepileptic drug (AED) therapy. Open-label LTG (LAMICTAL [reg]) was titrated according to labeling to a target dose of 300-500mg/day (100-400mg/day for patients on an AED regimen containing valproate), based on individualized adjustment and maintained for sixteen weeks. Patients on a single enyzme-inducing AED were eligible to convert to LTG monotherapy for an additional twelve weeks. Mood was assessed with the profile of mood states (POMS) at baseline. POMS total mood disturbance scores range from [minus]32 to 200 with higher scores indicating greater mood disturbance. Patients were divided into sub-groups by level of baseline mood disturbance (i.e., [le] 31, LO; 32-64, MED; [ge]65, HI). Seizure control was assessed with patient-completed diaries during the last eight weeks of each phase.
196 patients enrolled (mean age 43 years, 58% female, median baseline seizure frequency 2/month). At baseline, the majority of patients were taking older AEDs, primarily carbamazepine, phenytoin, and valproate. Of the 196 patients, 152 (78%) completed the adjunctive phase. Sixty-eight patients attempted conversion to monotherapy and 56 (82%) completed the monotherapy phase. Demographics were similar among the three sub-groups, however women were over-represented in the HI group. [table1]Despite low compliance rates with seizure diaries (~50%), similar improvements in seizure control were seen across the three sub-groups. One limitation of this analysis is the small number of patients that completed the entire study.
In a sample of patients from an outpatient study, similar levels of seizure control were obtained in patients treated with adjunctive and monotherapy lamotrigine regardless of baseline level of mood disturbance. Larger studies are needed to confirm this preliminary finding.
[Supported by: GlaxoSmithKline Research and Development]