BACKGROUND

Evidence for the risk and incidence of anticonvulsant-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in Japan is scarce.

METHODS

We conducted a matched case-control study using a large-scale Japanese claims database. SJS/TEN cases were identified using a claims-based algorithm developed in a previous study (sensitivity 76.9%, specificity 99.0%). Conditional logistic regression with Firth's bias correction to address an issue of rare events was used to estimate odds ratios (ORs) for SJS/TEN for each anticonvulsant use (90 days before the index date) versus non-use. 90-day cumulative incidence of SJS/TEN per 100,000 new users was calculated for 33 anticonvulsants. Causality between anticonvulsant use and SJS/TEN in each exposed case was assessed using the algorithm of drug causality for epidermal necrolysis (ALDEN) score.

RESULTS

From 5,114,492 subjects, we selected 71 SJS/TEN cases and 284 controls. We observed significantly increased ORs for SJS/TEN among new users of carbamazepine (OR 68.00) and lamotrigine (OR 36.00) with ALDEN scores of "probable" or higher. Cumulative incidence of SJS/TEN was 93.83 for carbamazepine and 84.33 for lamotrigine. One case newly exposed to phenytoin which developed SJS/TEN was rated "unlikely" in ALDEN causality, resulting in cumulative incidence of 66.27. Cumulative incidence of SJS/TEN was 25.23 for levetiracetam, 7.52 for clonazepam, and 1.23 for diazepam, but their ALDEN scores were "very unlikely".

CONCLUSIONS

This study is the first to document the differential risk of SJS/TEN for anticonvulsants in a real-world setting in Japan. Exposure to carbamazepine and lamotrigine was associated with an increased risk of SJS/TEN.