INTRODUCTION: Acute kidney injury is an expected adverse drug reaction listed in the European Union (EU) Summary of Product Characteristics (SmPC) for levetiracetam, one of the most widely used modern antiseizure medications (ASMs). Objective: We conducted a voluntary post-authorization safety study to characterize the rate of acute renal failure (ARF) in patients exposed to levetiracetam versus other ASMs.
METHODS: New users of ASMs without prior renal dysfunction were identified and followed for 30 days in the IBM® MarketScan® database (USA, January 2008-December 2017). ARF was defined as a diagnosis on inpatient or emergency department claims. We estimated adjusted incidence rates, incidence rate ratios (IRRs), and incidence rate differences (IRDs) of ARF in patients initiating levetiracetam versus other ASMs.
RESULTS: Overall, 110,336 patients were eligible for the monotherapy cohort and 96,215 were eligible for the polytherapy cohort. The overall crude rate of ARF following a new ASM was 6.0 and 6.5 per 10,000 patients for the 'monotherapy' and 'polytherapy' cohorts, respectively, in the first 30 days after the index date. In the monotherapy cohort, the IRR for ARF was 1.37 (95% confidence interval [CI] 0.80-2.34) and the corresponding IRD was 2.0 (95% CI - 1.12 to 5.12) additional ARFs per 10,000 patient-months. In the polytherapy cohort, the adjusted IRR for ARF was 0.94 (95% CI 0.51-1.74) and the corresponding IRD was - 0.42 cases per 10,000 patient-months (95% CI - 4.01 to 3.17).
CONCLUSIONS: The rate of ARFs in ASM new users was very low. In patients without prior ASMs, the estimated difference in risk of ARF associated with initiation of levetiracetam versus initiation of other ASMs was small, with 95% CIs compatible with small protective or harmful effects. In patients receiving polytherapy, the difference was compatible with the null and the 95% CI with small protective or harmful effects.
