Lacosamide-induced personality changes: An unexpected adverse effect

To describe an 'unexpected' case of abrupt personality following the introduction of lacosamide.

A description of an 82-year-old male receiving neurological follow-up since 2010 due to epilepsy secondary to haemorrhagic stroke. We report a case of abrupt personality change in an 82-year-old male following the introduction of lacosamide with a return to the previous state after its discontinuation. We explored possible mechanisms and pharmacokinetic concerns explaining this personality change.

In fact, a few days after introducing lacosamide, the patient was described as 'gentle', 'calm' and apologetic for his past aggressions against his family and caregivers which was in complete contrast to his usual personality. There was also marked insistence and the use of sexualised language towards women in his close circle, especially his home nurses. In view of his insistent behaviour towards his nurses and unusual sexualised language, lacosamide was withdrawn. A few days later, the patient displayed his usual, vindictive, aggressive and forceful character. He no longer made any sexualised remarks to his home nurses.

To our knowledge, this is the first case of a sudden behavioural and personality change reported by family, friends and carers following the introduction of lacosamide.