Impact of regulatory restrictions on the use of valproic acid in women of childbearing age: An Italian study

Objective: Due to significant risks to the offspring after intrauterine exposure, the European Medicines Agency issued recommendations in 2014 and 2018 restricting the use of valproate (VPA) in women of childbearing age (WOCA). We aimed to evaluate their impact in the Emilia-Romagna region (ERR) of Northern Italy. Methods: Using administrative databases, we identified all the ERR residents who received antiseizure medication (ASM) prescriptions from 2010 to 2020. Time series of incidence rates by sex and age group were evaluated for all ASMs. Focusing on VPA, an interrupted time series analysis was applied to assess the impact of the restrictions in WOCA with epilepsy (WOCA-E) and WOCA with psychiatric disorders (WOCA-P). We then evaluated the chronological order of ASM prescriptions with regard to the position of VPA. Results: Incidence rates of VPA prescriptions overall decreased over time. A significant decrease was observed only for females. The effect was stronger for WOCA, after both the first (incidence rate ratio [IRR] =.85, 95% confidence interval [CI] =.75–.96) and the second restriction (IRR =.67, 95% CI =.55–.82). The decrease was significant after the second restriction both for WOCA-E (IRR =.43, 95% CI =.27–.68) and for WOCA-P (IRR =.49, 95% CI =.35–.70), as well as VPA as a first prescription in both populations. VPA prescriptions as further choice did not show the same trend. Significance: After the regulatory restrictions, an overall significant decline in the use of VPA in WOCA was observed in ERR. The second restriction has been effective in consolidating the prescription trend. However, VPA appears still to be a commonly used drug in WOCA when other ASMs have failed.