LAUSR

OBJECTIVE The aim of this study was to explore the prescription pattern of antiepileptics and the relationship between antiepileptics and adverse drug reactions (ADRs) in a Japanese population. METHODS A retrospective observational cohort study was conducted by reviewing the medical records of patients who visited or were admitted to a single tertiary care center between January 2011 and June 2019, were treated with antiepileptics, and developed allergic ADRs associated with these drugs. RESULTS In total, 14,230 unique patients received antiepileptics during the study period. Diazepam was the most frequently used antiepileptic drug (74.8 %), followed by phenobarbital (14.3 %), valproic acid (11.4 %), fosphenytoin (10.0 %), and carbamazepine (7.3 %). Although a trend of increasing prevalence of newer generation antiepileptics was noted, most patients are still treated with older generation antiepileptics. Thirty-two (0.22 %) unique patients experienced ADRs associated with antiepileptics, and the antiepileptic drug most frequently associated with ADRs was carbamazepine, at a rate of 1.4 %. Three patients developed Stevens-Johnson syndrome/toxic epidermal necrolysis, in two of which carbamazepine was implicated. Most patients experienced ADRs associated with aromatic antiepileptics (84.4 %) or older generation antiepileptics (81.3 %). SIGNIFICANCE This is the first study to assess the relationship between ADRs and antiepileptics at a tertiary care center in Japan. Based on our results, most patients were prescribed older generation antiepileptics, and most ADR events were linked to the administration of drugs in this category; thus, identification of patients at risk of developing ADRs is critical in order to prevent such events.