Late cognitive effects of early treatment with phenobarbital

We previously reported that IQ was significantly lowered in a group of todd ler-aged children randomly assigned to receive phenobarbital or placebo for febrile seizures and there was no difference in the febrile seizure recurr ence rate. We retested these children 3-5 years later, after they had enter ed school, to determine whether those effects persisted over the longer ter m and whether later school performance might be affected. On follow-up test ing of 139 (of the original n=217) Western Washington children who had expe rienced febrile seizures, we found that the phenobarbital group scored sign ificantly lower than the placebo group on the Wide Range Achievement Test ( WRAT-R) reading achievement standard score (87.6 vs 95.6; p=0.007). There w as a nonsignificant mean difference of 3.71 IQ points on the Stanford-Binet , with the phenobarbital-treated group scoring lower (102.2 vs 105.7; p=0.0 9). There were five children in our sample with afebrile seizures during th e 5-year period after the end of the medication trial. Two had been assigne d to phenobarbital, and three had been in the placebo group, We conclude th ere may be a long-term adverse cognitive effect of phenobarbital on the dev elopmental skills (language/verbal) being acquired during the period of tre atment and no beneficial effect on the rate of febrile seizure recurrences or later nonfebrile seizures.