Hydroxyzine Initiation Following Drug Safety Advisories on Cardiac Arrhythmias in the UK and Canada: A Longitudinal Cohort Study

Richard L Morrow, Barbara Mintzes, Patrick C Souverein, Christine E Hallgreen, Bilal Ahmed, Elizabeth E Roughead, Marie L De Bruin, Sarah Brøgger Kristiansen, Joel Lexchin, Anna Kemp-Casey, Ingrid Sketris, Dee Mangin, Sallie-Anne Pearson, Lorri Puil, Ruth Lopert, Lisa Bero, Danijela Gnjidic, Ameet Sarpatwari, Colin R Dormuth

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

INTRODUCTION: Regulatory advisories on hydroxyzine and risk of QT prolongation and Torsade de pointes (TdP) were issued in the UK in April 2015 and Canada in June 2016. We hypothesized patients with risk factors for QT prolongation and TdP, compared with those without risk factors, would be less likely to initiate hydroxyzine in the UK and in British Columbia (BC), Canada, following advisories.

METHODS: We conducted a longitudinal study with repeated measures, and evaluated hydroxyzine initiation in a UK cohort and a concurrent BC control cohort (April 2013-March 2016) as well as in a BC advisory cohort (June 2014-May 2017).

RESULTS: This study included 247,665 patients in the UK cohort, 297,147 patients in the BC control cohort, and 303,653 patients in the BC advisory cohort. Over a 12-month post-advisory period, hydroxyzine initiation decreased by 21% in the UK (rate ratio 0.79, 95% confidence interval 0.66-0.96) relative to the expected level of initiation based on the pre-advisory trend. Hydroxyzine initiation did not change in the BC control cohort or following the Canadian advisory in the BC advisory cohort. The decrease in hydroxyzine initiation in the UK in the 12 months after the advisories was not significantly different for patients with risk factors compared with those without risk factors.

CONCLUSION: Hydroxyzine initiation decreased in the UK, but not in BC, in the 12 months following safety advisories. The decrease in hydroxyzine initiation in the UK was not significantly different for patients with versus without risk factors for QT prolongation and TdP.

Original languageEnglish
Pages (from-to)623-638
JournalDrug Safety
Volume45
Issue number6
Early online date19 Apr 2022
DOIs
Publication statusPublished - Jun 2022

Bibliographical note

Funding Information:
This work was funded by grants from the Canadian Institutes of Health Research (CIHR; PJT–153275) and the Australian Government National Health and Medical Research Council (NHMRC; 1122332). Ameet Sarpatwari’s work is also funded by Arnold Ventures.

Publisher Copyright:
© 2022, The Author(s).

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