Antiepileptic drug hypersensitivity syndrome: in vitro and clinical observations.

Four patients who manifested symptoms of the antiepileptic drug (AED) hypersensitivity syndrome during therapy with carbamazepine are reported. In 3 patients, the syndrome was exacerbated after conversion of therapy to another antiepileptic drug with an aromatic ring chemical structure. In vitro lymphocyte transformation studies confirmed cross-reactivity to one or more aromatic AEDs in 3 patients. In all patients, discontinuation of aromatic AEDs resulted in resolution of symptoms and in 3 patients who required continued AED therapy, valproic acid was well tolerated.