Abstracts

Rationale: Allergic reaction to specific antiepileptic drugs (AEDs) can occur in some patients and require a change of therapy. An alternative strategy is to desensitize the patients to the offending drug. This study aimed to investigate the usefulness and safety of desensitization to oxcarbazepine (OXC) and ethosuximide (ETX) in patients who have had genetic screening for the human leukocyte antigen (HLA) alleles. Methods: We enrolled total 19 patients who previously showed positive response, but hypersensitivity reactions to OXC or ETX. They had to be discontinued the medications. Although alternative antiepileptic drugs were tried on our patients, their seizures were refractory to other drugs. Therefore, desensitization to OXC was tried in 17 children with partial seizures and one child with paroxysmal kinesigenic dyskinesia (PKD), and to ETX was attempted in one child with atypical absence seizures. High-resolution human leukocyte antigen (HLA)-A, and -B genotyping was performed to investigate the association between specific HLA allele and OXC-induced cutaneous adverse drug reactions. Results: The mean age of desensitization was 10.5 ± 3.6 years (range 5.1-16.2 years) and the mean duration of follow-up after desensitization was 14.4 ± 8.7 months (range 3-34 months). Eighteen patients completed the desensitization protocol to a target dosage over 2-5 months. Five children developed mild itching and erythema during desensitization, but the symptoms disappeared after the next dose increasing was withheld for a short period. We did not find specific HLA genotypes associated with OXC-induced cutaneous adverse drug reactions. The frequency of seizure and attack in PKD was reduced to less than baseline in 17 patients except for one child. At last follow-up, eight patients were seizure-free, six patients showed > 90% reduction and the other three patients had > 50% reduction. Conclusions: The desensitization protocol was well tolerated and safe without serious allergic reactions. When allergic reactions occur with OXC or ETX and there are no effective alternatives, desensitization can be a useful treatment modality.