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Article History

Accepted: 20 December 2021

First Online: 22 January 2022

Declarations

:

: This research was supported by the Primary Care Research Trust of Birmingham and Midlands Research Practices Consortium, who provided the funding to purchase the sales data from IQVIA.

: GCR was financially supported by the National Institute for Health Research (NIHR) School for Primary Care Research (SPCR), the Naji Foundation, and the Rotary Foundation to study for a Doctor of Philosophy (2017-2020) but no longer has any financial conflicts of interest. GCR is an associate editor of <i>BMJ Evidence Based Medicine</i>. JKA has published articles and edited textbooks on adverse drug reactions and interactions and has often given medicolegal advice, including appearances as an expert witness in coroners' courts, often dealing with the adverse effects of opioids. BM works for NHS England as a pharmacist adviser. BG has received research funding from the Laura and John Arnold Foundation, the NIHR, the NIHR SPCR, the NIHR Oxford Biomedical Research Centre, the Mohn–Westlake Foundation, NIHR Applied Research Collaboration Oxford and Thames Valley, the Wellcome Trust, the Good Thinking Foundation, Health Data Research UK, the Health Foundation, and the WHO; he also receives personal income from speaking and writing for lay audiences on the misuse of science. FDRH acknowledges part support from the NIHR SPCR, the NIHR Applied Research Collaboration Oxford Thames Valley, and the NIHR Oxford Oxford University Hospitals Biomedical Research Centre (OUH BRC). CH is an NIHR senior investigator and has received expenses and fees for his media work, expenses from the WHOand the US FDA, and holds grant funding from the NIHR SPCR and the NIHR SPCR Evidence Synthesis Working Group (project 380), the NIHR BRC Oxford and the WHO. On occasion, CH receives expenses for teaching evidence-based medicine and is also paid for his general practitioner work in the NHS out of hours (contract with Oxford Health NHS Foundation Trust). CH is the Director of the Centre for Evidence-Based Medicine. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care.

: Study materials are available on an open repository [CitationRef removed] (ExternalRef removed). We cannot openly share the data because of contractual agreements with IQVIA, but the data can be accessed directly from IQVIA, which will require a fee.

: Our statistical code is openly available at GitHub [CitationRef removed] (ExternalRef removed).

: GCR devised the research question; designed the methods; wrote the protocol; conducted a literature search; sourced, cleaned, managed, and analysed the data; created the figures; and wrote the first draft of the manuscript. JKA and CH reviewed the protocol and preliminary findings and provided supervisory support. FDRH reviewed the protocol and facilitated the grant application. BM reviewed preliminary findings and contributed to the interpretation of data. BG provided supervisory support. All authors read and approved the final version.

: Not applicable.

: Not applicable.

: All authors read and approved the final manuscript and consent to submit the manuscript for publication.