[Successful induction of tolerance in an epilepsy patient with phenobarbital allergy]

We report on a 32-year-old female patient who had had a history of complex partial seizures since the age of 14. Phenobarbital was the most effective anticonvulsant drug in this patient. However, the drug treatment was complicated by a phenobarbital-induced exanthematous eruption. Reintroduction of the phenobarbital some years later resulted in a skin rash again; therefore, treatment with this substance had to be discontinued a second time. Because of the satisfactory antiepileptic efficacy, phenobarbital was introduced a third time using a desensitization procedure with increased oral doses, starting with a dose of 1 mg. After a daily dose of 90 mg phenobarbital, on day 6 an exanthematous eruption appeared. The exanthem disappeared parallel to a dose reduction of phenobarbital and with a gradually increasing dosage up to a maintenance dose of 200 mg. Tolerance to the allergic effect of phenobarbital was preserved and the seizure frequency was significantly reduced by phenobarbital monotherapy with a daily dose of 200-175 mg.