Lack of efficacy and potential aggravation of myoclonus with lamotrigine in Unverricht-Lundborg disease.

PURPOSE

Unverricht-Lundborg disease (ULD) is a progressive myoclonus epilepsy with tonic-clonic seizures, action myoclonus, mild ataxia, without dementia. Persistence of invalidating action myoclonus is a major problem. Drugs like phenytoin can aggravate ULD. In this study, we retrospectively analyzed the effect of add-on lamotrigine (LTG) in the five patients under our care who received LTG.

METHOD

Three men and two women, aged 20-50 years who had ULD confirmed by molecular biology, followed in two epilepsy centers, received add-on LTG at 50-300 mg/d. All of them had valproate. The other drugs used in cotherapy were high-dose piracetam, benzodiazepines phenobarbital, topiramate, and primidone. The assessment of LTG was based on detailed interview and clinical examination. Aggravation was diagnosed when myoclonic jerks (MJ) increased without irregular intake of medication, inappropriate lifestyle, encephalopathic or metabolic complications, or overdosage.

RESULTS

In two patients, LTG exacerbated MJ in a dose-dependent manner. In one patient, a delayed, severe exacerbation of myoclonus occurred that only ceased after LTG withdrawal and introduction of levetiracetam. These three patients had minor forms of ULD. In two patients with moderate to severe forms of ULD, LTG had no effect.

CONCLUSION

Although symptoms may fluctuate in ULD, it was possible to pinpoint lack of improvement (2/5), dose-related exacerbation of myoclonus (2/5), and putative late-onset aggravation (1/5) in five patients treated with adjunctive LTG. LTG does not appear to be a sensible treatment option in ULD.