Efficacy and tolerability of add-on Lacosamide treatment in adults with Lennox-Gastaut syndrome: An observational study.

Purpose: To evaluate the efficacy, safety, and tolerability of lacosamide in adults with LGS in the clinical setting.

Method: The present report is a retrospective, open-label treatment study carried out from June 2013 to December 2014 at the National Institute of Colombia. Lacosamide was introduced as add-on therapy. All caregivers were instructed to initiate lacosamide at low doses (25-50 mg) and gradually increasing it every 2 weeks. The efficacy was evaluated based on the reduction in the rate of each countable type of seizure. We also evaluated the retention rate for lacosamide as the number of days with lacosamide during follow-up. The tolerability was evaluated base on account the adverse events.

Results: We found that lacosamide only improves the seizure rate in three out of 19 patients with LGS, in two of them by more than 50%. The highest seizure reduction rate was observed in the focal and tonic-clonic seizures. The most commonly reported adverse events were worsening of seizures, aggressiveness and irritability. Nine patients (47.4%) showed worsening of their behavior during the treatment with lacosamide.

Conclusion: Lacosamide can exacerbate both, the tonic and astatic seizures, and the encephalopathy associated with this epileptic syndrome. However, it is interesting to consider the likelihood of suppression of generalized tonic-clonic and focal seizures. That is why; lacosamide could be an option after carefully balancing risks and benefits in each individual case.