This study aimed to evaluate the long-term efficacy and safety of
topiramate in treating children with
drug-resistant epilepsy. A multicentric, retrospective, open-label, add-on study was undertaken of 277 children (mean age 8.4 years; range 12 months to 16 years) affected by
drug-resistant epilepsy. The efficacy was rated according to the seizure types and
epilepsy syndrome. After a mean period of 27.5 months of treatment (range 24-61 months), 11 patients (4%) were seizure free and 56 (20%) had more than 50% reduction in seizure frequency. The efficacy of
topiramate treatment was noted in
localization-related epilepsy and in
generalized epilepsy. In addition, in a group of 114 patients, we compared the initial efficacy (evaluated after a mean of 9 months of follow-up) and the retention at a mean of 30 months of
topiramate with regard to loss of efficacy (defined as the return to the baseline seizure frequency). Fifty-five (48%) of 114 patients were initial responders. The retention at a mean of 30 months was 23 of 114 patients (20%), 4 of whom (3.5%) were still seizure free. A loss of efficacy occurred in 32 of the 55 initial responders (58%). It was prominent in patients with
generalized epilepsy, such as
symptomatic infantile spasms and
Lennox-Gastaut syndrome, as well as in those with
Dravet syndrome. By contrast, a well-sustained
topiramate efficacy was noted among patients with
localization-related epilepsy. Globally, adverse events were observed in 161 patients (58%) and were mainly represented by
weight loss,
hyperthermia, sedation, and nervousness, which, in most cases, disappeared after slowing titration or reducing the dosage of the drug. In conclusion, the present long-term study confirms that
topiramate represents a useful drug effective in a wide range of
seizures and
epilepsy syndromes. Moreover, preliminary data seem to suggest that the efficacy of
topiramate, when evaluated in the long-term perspective, is more sustained in
localization-related epilepsy than in
generalized epilepsy.