[Efficacy and failure of phenobarbital in the prevention of febrile convulsions. Importance of familial antecedents].

The authors analyze the value of phenobarbital for prophylaxis of new convulsions in a group of 370 patients who had previously had febrile seizures. Percentage of recurrences in phenobarbital treated cases (4 +/- 0,6 mg/Kg/d) was 18,67%, versus 55,89% in untreated children (p less than 0.001). The presence of family history of epileptic or febrile seizures is a risk factor (p less than 0.01) that facilitates failure of phenobarbital prophilaxis in future febrile seizures.