Desensitization to oxcarbazepine: Long-term efficacy and tolerability

Background and Purpose Antiepileptic drug (AED)-associated cutaneous adverse drug reactions can lead to the discontinuation of medications. The aim of this study was to determine the long-term efficacy and safety of performing desensitization to oxcarbazepine. Methods This study involved 20 patients who exhibited cutaneous adverse drug reactions associated with oxcarbazepine use between July 2009 and March 2016 at Samsung Medical Center. All of the participants had to discontinue oxcarbazepine despite presenting initially positive responses. Human leukocyte antigen genotyping was performed to detect the genetic predisposition to Stevens-Johnson syndrome. The desensitization to oxcarbazepine was performed with a starting dosage of 0.1 mg/day. Efficacy was evaluated by comparing the frequency of seizures before and at 1 and 3 years after desensitization. Adverse events occurring during desensitization and the retention rate after desensitization were also investigated. Results Nineteen patients (95%) safely completed the desensitization protocol. One withdrew owing to emotional problems that appeared to be associated with oxcarbazepine. The follow-up period was 4.6±1.2 years (mean±SD), and oxcarbazepine was maintained for more than 3 years after desensitization in 15 patients (83.3%). The response rates were 84.2% and 77.8% at 1 and 3 years after desensitization, respectively. Eight patients remained seizure-free for 3 years, and two discontinued all AEDs. Transient adverse reactions such as mild rash and itching were reported by five patients during desensitization. Conclusions This study has demonstrated the long-term efficacy and safety of desensitization to oxcarbazepine in patients exhibiting cutaneous adverse drug reactions. This favorable outcome should encourage the implementation of desensitization in patients presenting with hypersensitivity to oxcarbazepine as an alternative strategy in clinical practice.