OBJECTIVE: To describe the long term efficacy and tolerance of stiripentol 
associated with valproate and clobazam in an exhaustive cohort of patients with 
severe myoclonic epilepsy of infancy (Dravet's syndrome), in which short term 
efficacy of such a treatment has recently been demonstrated in a 
placebo-controlled trial.
RESULTS: In 46 patients the frequency and the duration of seizures was 
significantly reduced (p < 0.001) as well as the number of convulsive status at 
a median of three-year follow-up. Ten patients were dramatically improved 
(seizures significantly decreased in number [p = 0.002] and duration [p = 0.002] 
and status epilepticus disappeared), 20 were moderately improved (seizures 
significantly decreased in duration [p = 0.001] and status were less numerous), 
four had no response and efficacy was non evaluable in 12 mainly because of 
adverse events. Efficacy was better in the youngest patients. The most frequent 
adverse events were loss of appetite and loss of weight. They could be so severe 
in patients over 12 years of age that the stiripentol dosage could not be 
increased to 50 mg kg-1 j-1.
CONCLUSION: This follow-up study shows that stiripentol added to valproate and 
clobazam maintains its efficacy at long term in children with severe myoclonic 
epilepsy of infancy and suggests that the tritherapy should be introduced as 
early as possible in these patients in order to suppress the convulsive status 
epilepticus.