Sibling response to initial antiepileptic medication predicts treatment success.

OBJECTIVE: A recent study focusing on a response to antiepileptic drugs (AED) among siblings for epilepsy showed a similar response among epileptic siblings to specific AEDs or AED combinations. Currently, however, family history of treatment response to AEDs is not readily employed in deciding which initial medication to use when treating patients with epilepsy. We tested the hypothesis that sibling response to initial AED predicts treatment success.

METHODS: Presumed siblings were identified from a single-center database of patients diagnosed with epilepsy by matching last name, address, and name of parent(s). We identified 28 sibling pairs and two sibling trios with epilepsy. Seventeen of these sibling pairs were started on the same initial AED, with 15 sibling pairs having the same type of epilepsy. The remaining 11 pairs were started on a different initial AED, with 8 of these sibling pairs having the same type of epilepsy. Subjects with seizure freedom for a period of ≥1year were classified as a "responder".

RESULTS: When at least one of the sibling pair responded to an initial AED, the proportion of the other siblings also responding to the initial AED was significantly higher if the siblings were treated with the same AED (8/11) compared to siblings who were treated with different AED (1/10) (Fisher's exact test, p-value=0.0075).

SIGNIFICANCE: These findings suggest that sibling response to initial AED is predictive of the success of AED therapy. This study is limited by a small cohort and retrospective design. Future, larger prospective studies are needed to reproduce and further validate these findings.