Impact of EMA 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

Unintended impact of pharmacovigilance regulatory interventions: A systematic review

AIMS

Studies assessing the impact of pharmacovigilance regulatory interventions often focus on the expected (or intended) outcomes, while any possible unintended impact may be overlooked. The update of the Good Pharmacovigilance Practice guideline in 2017 elaborated on impact assessment, emphasizing the need also to assess possible unintended impact. This systematic literature review investigated how often the unintended impact of regulatory interventions was considered in publications of studies investigating pharmacovigilance regulatory interventions in Europe.

METHODS

We conducted a systematic review of the literature on MEDLINE and EMBASE from 1 January 2012 to 28 February 2022 to identify publications that investigated the impact of regulatory interventions in Europe. The primary outcome of the study was the number of publications reporting assessments of unintended impact. In addition, we studied the characteristics of these publications, including the type of outcomes assessed, the analytical methods applied and the type of data used.

RESULTS

In total, 96 publications were included in the analysis. The unintended impact of pharmacovigilance regulatory interventions was investigated in 23 of 96 publications (24%). The drug classes most frequently studied in the publications assessing unintended impact of regulatory interventions were oral glucose-lowering drugs (n = 6, 26%), opioids (n = 4, 17%), antidepressants (n = 4, 17%) and antipsychotics (n = 3, 13%). The reported methods to assess the unintended impact were interrupted time series (n = 10, 43%) and descriptive statistics with or without significance testing (n = 2 [9%] and n = 9 [39%], respectively). The outcomes selected for unintended impact assessments included the use of other drugs (n = 16, 70%), health outcomes (n = 8, 35%) and behavioural changes (n = 4, 17%). Most of the publications reported on the use of electronic health record databases (n = 13, 57%) or claims databases (n = 13, 57%), while registries were used in 4 publications (17%).

CONCLUSION

The unintended impact of pharmacovigilance regulatory interventions was reported in only a quarter of identified publications. There was no apparent increase in attention to unintended impact assessments after the update of the Good Pharmacovigilance Practice guidelines.

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

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-022-01175-2.

Efficacy and Safety of Non-brain Penetrating H1-Antihistamines for the Treatment of Allergic Diseases

H₁ receptor antagonists, known as H₁-antihistamines (AHs), inactivate the histamine H₁-receptor thereby preventing histamine causing the primary symptoms of allergic diseases, such as atopic dermatitis, pollinosis, food allergies, and urticaria. AHs, which are classified into first-generation (fgAHs) and second-generation (sgAHs) antihistamines, are the first line of treatment for allergic diseases. Although fgAHs are effective, they cause adverse reactions such as potent sedating effects, including drowsiness, lassitude, and cognitive impairment; anticholinergic effects, including thirst and tachycardia. Consequently, the use of fgAHs is not recommended for allergic diseases. Today, sgAHs, which are minimally sedating and, therefore, may be used at more effective doses, are the first-line treatment for alleviating the symptoms of allergic diseases. Pharmacologically, the use of sedating fgAHs is limited to antiemetics, anti-motion sickness drugs, and antivertigo drugs. The use of histamine H₁-receptor occupancy (H₁RO) based on positron emission tomography (PET) has been developed for the evaluation of brain penetrability. Based on the results of the H₁RO-PET studies, non-brain-penetrating AHs (nbpAHs) have recently been reclassified among sgAHs. The nbpAHs are rapidly acting and exhibit minimal adverse reactions and, thus, are considered first-line drugs for allergic diseases. In this review, we will introduce recent topics on the pharmacodynamics and pharmacokinetics of AHs and make recommendations for the use of nbpAHs as first-line treatment options for allergic diseases.