Continuous sodium valproate or phenobarbitone in the prevention of 'simple' febrile convulsions. Comparison by a double-blind trial.

Of the 265 children aged between 6 and 18 months admitted to hospital in a 26-month period each with his first febrile convulsion, there were 64 who satisfied our criteria for a simple febrile convulsion. Of these, 43 (random) were entered into a double-blind trial of continuous sodium valproate versus phenobarbitone, and 21 were untreated. The dosage was phenobarbitone 3-6 mg/kg per day; sodium valproate 30-60 mg/kg per day. 39 completed treatment (21 phenobarbitone, 18 sodium valproate), 2 in each group being withdrawn because of unacceptable side effects. Close supervision and random serum drug estimations showed compliance to be good. After a mean treatment period of 12 months (mean age 25 months) there had been one recurrence in the sodium valproate group compared with 7 in the untreated group (P less than 0.05), and 4 recurrences in the phenobarbitone group. The difference between treatment and no treatment was significant (P less than 0.05). These results suggest that in simple febrile convulsions occurring between 6 and 18 months of age sodium valproate is as effective as phenobarbitone in preventing recurrence and that either treatment is better than none.