Older individuals may be more susceptible to cognitive side effects of antiepileptic drugs than are younger adults. This randomized, double-blind study compared the cognitive effects of lamotrigine (median maintenance dosage, 500.0 mg/d) and topiramate (median maintenance dosage, 300.0 mg/d) as adjunctive therapy for 16 weeks in patients ≥50 years of age. Fifty-one patients (lamotrigine, n=25; topiramate, n=26) were enrolled, and 28 patients (lamotrigine, n=15; topiramate, n=13) completed the study. In a combined analysis of all cognitive tests performed, no significant differences between treatment groups were noted. However, analyses of individual cognitive test results revealed that lamotrigine-treated patients had significantly better results on the Controlled Oral Word Association Test and the Symbol-Digit Modalities Test, whereas topiramate-treated patients had significantly more favorable results on the Digit Cancellation Test and the Rey Auditory-Verbal Learning Test. Larger studies are needed to further clarify the differences in the cognitive effects of lamotrigine and topiramate in older patients.
Epilepsy; Lamotrigine; Topiramate; Cognition