Tolerability of lacosamide or zonisamide in elderly patients with seizures

The prevalence of seizures in the elderly will increase as populations age. Data is currently limited regarding treatment and especially tolerability of newer antiseizure medications (ASMs). In the current study we aimed to investigate the tolerability of lacosamide (LCS) and zonisamide (ZNS).

We performed a retrospective chart review of patients with seizures older than 60 treated with LCS or ZNS in the outpatient setting. We examined seizure variables, medical comorbidities, and concomitant medications. Primary outcomes were the retention rates at last follow up, and the discontinuation rate due to side effects.

Seventy-one (71) LCS and 39 ZNS patients were identified. Average age at LCS initiation was 71.0±7.0 years and 49% were medically refractory. Average duration of follow up was 23.1±21.2 months. At last follow up, the retention rate was 60% and seizure freedom rate 52%. Of the 19 discontinuations due to side effects, 7 (37%) were due to dizziness/gait instability. No predictors of discontinuation were identified. Average age at ZNS initiation was 69.7±6.9 years and 51% were medically refractory. Average duration of follow up was 46.3±38.3 months. At last follow up, the retention rate was 64% and seizure freedom rate was 67%. Of the 12 discontinuations due to side effects, 4 (33%) were due to cognitive or behavioral side effects. Predictors of discontinuation included a lower starting dose.

Lacosamide and zonisamide are viable options for the treatment of epilepsy in the elderly and have similar retention rates.