Subjective preference for lamotrigine or topiramate in healthy volunteers: relationship to cognitive and behavioral...

Outcomes research emphasizes patient self-assessment and preferences in optimizing treatment. We previously showed that lamotrigine produces significantly less cognitive and behavioral impairment compared with topiramate. In the current study we extend these observations to subject self-report of preference for lamotrigine or topiramate independent of potentially confounding effects of seizures or seizure control. Additionally, drug preference was related to effects of lamotrigine and topiramate on objective neuropsychological tests as well as self-perception on behavioral instruments.

Thirty-seven healthy volunteers completed a double-blind, randomized crossover design incorporating two 12-week treatment periods of lamotrigine and topiramate each titrated to a dose of 300 mg/day. Evaluation of 23 objective neuropsychological and 15 subjective behavioral measures occurred at four times: pretreatment baseline, first treatment, second treatment, and posttreatment baseline. Preference for lamotrigine or topiramate was assessed, while blinding was maintained, at the final study visit when each subject was asked which drug he or she would prefer to take.

A large majority (70%) preferred lamotrigine, 16% stated preference for topiramate, and 14% had no preference (drugs equivalent). Consistent with preference, those preferring lamotrigine performed better on 19 of 23 objective and 13 of 15 subjective behavioral measurements while on lamotrigine. Inconsistent with preference, subjects preferring topiramate performed better on 19 of 23 objective and 9 of 15 subjective behavioral measures while on lamotrigine. Topiramate preference also did not correlate with IQ, serum concentration, body mass index, age, or gender. Topiramate preference did relate to responses on the Profile of Mood States.

Lamotrigine was preferred by the majority of subjects, congruent with objective neuropsychological and subjective behavioral measures. In contrast, for those stating a preference for topiramate the results on objective neuropsychological measures were impaired while fewer complaints were noted on the Profile of Mood States. This suggests that preference for topiramate may be determined by an effect on mood.