Impact of <scp>EMA</scp> regulatory label changes on hydroxyzine initiation, discontinuation and switching to other medicines in Denmark, Scotland, England and the Netherlands: An interrupted time series regression analysis

Abstract Background Hydroxyzine is indicated for the management of anxiety, skin and sleep disorders. In 2015, European Medicines Agency (EMA) concluded that hydroxyzine was pro‐arrhythmogenic changes to product information were implemented in Europe. This study aimed evaluate their impact Denmark, Scotland, England Netherlands. Method Quarterly time series analyses measuring initiation, discontinuation, switching other antihistamines, benzodiazepines antidepressants England, Scotland Netherlands from 2009 2018. Data analysed using interrupted regression. Results initiation quarter one 2010 per 100 000 was: 23.5, 91.5, 35.9 34.4 respectively. Regulatory action associated with a significant: immediate fall (−12.05, 95%CI −18.47 −5.63) (−19.01, −26.99 −11.02); change negative trend 000/quarter (−1.72, −2.69 −0.75) (−2.38, −3.32 −1.44). rise discontinuation (3850, 440‐7240). No consistent observed or Denmark. no following any country. Conclusion The 2015 EMA regulatory heterogeneous reductions varying by There limited on strong evidence suggesting unintended consequences major antidepressants.