Seizure exacerbation and developmental regression with carbamazepine.

Background: Unexpected exacerbation of seizures may occur following initiation of treatment with carbamazepine (CBZ). We reviewed the occurrence of such reactions in our patient population at a tertiary care children's hospital.

Methods: A retrospective analysis of our clinic database identified 129/691 (18.6%) patients with epilepsy treated with CBZ, as monotherapy. 38/129 children were later switched to another drug. In 11/38 (28.5%) clinical and/or EEG deterioration was observed. Two patients identified at another institution with similar exacerbation were also included in our analysis. We report on the findings in these 13 cases.

Results: Two groups were identified: Group I--6 patients with normal neurological exam, normal EEG background, and a diagnosis of idiopathic generalized epilepsy. Group II--7 patients with an abnormal neurological exam and/or abnormal EEG background. Following introduction of CBZ therapy, worsening of preexisting seizures, appearance of new seizure types, behavioral regression, and accompanying EEG deterioration were reported in both groups. Dramatic improvement in seizure control occurred, following withdrawal of CBZ and substitution of another anticonvulsant.

Conclusion: Physicians treating epilepsy must be aware that CBZ can exacerbate seizures, and cause developmental regression in children. Careful patient selection, when choosing CBZ as treatment, and prompt recognition of clinical deterioration and intervention, may help avoid or reverse these paradoxical reactions.