This report describes the long-term follow-up of 56 patients with refractor
y partial epilepsy who, within 3 months of vigabatrin add-on therapy (3 g/d
ay), showed a reduction in monthly seizure frequency of more than 50%. The
short-term (6 months) and long-term (5 years) effects of vigabatrin on seiz
ure frequency in this patient cohort have been published separately. The re
duction in seizure frequency appeared to be long-lasting in the patients fo
llowed-up (n = 36) and, importantly, a significant number of the patients (
n = 7) became seizure-free, especially during long-term treatment. Thus, th
e efficacy of vigabatrin appears to be progressive, at least in patients wh
o show an early response to treatment. These results are consistent with ex
perimental findings that suggest that vigabatrin may have anti-epileptogeni
c and neuroprotective effects.