Purpose: This study was to evaluate the efficacy and safety of topiramate (TPM) in patients with severe myoclonic epilepsy in infancy (SMEI) and refractory seizures.
Methods: We performed a prospective multicentric open label add-on study in 18 patients (age 2-21 years, mean 9 years) with SMEI and refractory seizures of different types. TPM was added to one or two other baseline drugs and the efficacy was rated according to seizure type and frequency.
Results: TPM was initiated at a daily dose of 0.5-1 mg/kg, followed by a 2-week titration at increments of 1-3 mg/kg/24 h up to a maximum daily dose of 12 mg/kg. After a mean period of 11.9 months (range 2-24 months), three patients (16.7%) had 100% fewer seizures and ten patients (55.5%) had a more than 50% seizure decrease. In no patient there was a seizure worsening. Mild to moderate adverse events were present in four patients (22.2%), represented by weight loss, hypermenorrhoea, renal microlithiasis, nervousness and dysarthric speech.
Conclusion: TPM may be a useful drug in patients with SMEI, being particularly effective against generalized tonic-clonic seizures. Further studies are needed to evaluate the early use of this drug in such a severe syndrome.