Incidence of Antiseizure Medication–Induced Severe Cutaneous Adverse Reactions in Malaysia

Antiseizure medication can potentially cause severe cutaneous adverse reactions, and certain antiseizure medication-induced severe cutaneous adverse reactions are associated with specific human leukocyte antigen alleles. This caused a change in antiseizure medication prescribing patterns, which may influence the incidence of antiseizure medication-induced severe cutaneous adverse reactions. Thus, we aimed to determine the incidence of antiseizure medication-induced severe cutaneous adverse reactions and its change over 15 years (2006-2019) in Malaysia. This retrospective analysis combined antiseizure medication-induced SCAR cases from the national adverse drug reaction database in the National Pharmaceutical Regulatory Agency, antiseizure medication usage data from the Malaysian Statistics of Medicine, and prescribing data from University Malaya Medical Centre, a national-level tertiary hospital to calculate antiseizure medication-induced SCAR incidence in Malaysia. We observed an upward trend in reported antiseizure medication-induced SCAR cases from 28 cases in 2006 to 92 in 2016. The incidence of carbamazepine (CBZ)-induced severe cutaneous adverse reactions increased from 7.5 per 1000 person-years (2006) to 17.8 per 1000 person-years (2016) but dropped to 7.2 per 1000 person-years subsequently (2019). Concurrently, there was an increase in the incidence of severe cutaneous adverse reactions secondary to phenytoin and lamotrigine. The prevalent users of CBZ had reduced from 22.8% (2006) to 14.1% (2016), whereas the levetiracetam and sodium valproate users increased by 5.5% and 4.8%, respectively. The incidence of CBZ-induced severe cutaneous adverse reactions had reduced since 2016, probably related to the implementation of human leukocyte antigen-B*1502 screening in Malaysia or substitution of CBZ with other antiseizure medications. However, this was accompanied by an increase in SCAR incidence related to phenytoin and lamotrigine.