Topiramate: new indication. Single-agent therapy in refractory epilepsy: for a few patients only
Prescrire International 13(73): 165-167
2004
ISSN/ISBN: 1167-7422 PMID: 15499695 Document Number: 572135
(1) Topiramate is helpful for some adults and children (aged over 4 years) with partial or generalised epilepsy, when combined with an inadequate ongoing treatment. (2) The indications for topiramate have now been extended in France to cover single-agent therapy of refractory epilepsy, from the age of 2 years. (3) A dose-finding study of 48 patients with refractory partial epilepsy suggests that the efficacy of topiramate monotherapy is dose-dependent. In a non comparative trial in 170 patients with refractory partial or generalised epilepsy, 12 patients were able to switch to topiramate alone after a phase of combining topiramate with their ongoing treatment. (4) The licence extension to children over 2 years of age is based solely on the results of previous trials. (5) Two dose-finding studies, and a trial versus a standard antiepileptic in which topiramate was used alone, confirmed that the safety profile of topiramate is similar to that of other antiepileptics, neuropsychological disturbance predominating. (6) Other adverse effects more specific to topiramate include cognitive and language problems, weight loss and reduced appetite, acute myopias sometimes associated with intraocular hypertension, an increased risk of renal lithiasis, reduced sweating with a risk of hyperthermia, and metabolic acidosis. (7) In practice, some patients whose epilepsy is refractory to an optimally administered treatment may improve when topiramate is added; and a small minority of them can gradually discontinue their previous treatment.