Conflict of Interest Disclosures: Ms Ferris reported receiving grants from the Bureau of Justice Assistance Harold Rogers Prescription Drug Monitoring Program Category 2 during the conduct of the study and being employed by Audacious Inquiry and contracted full time with the Chesapeake Regional Information System for our Patients, the Maryland state-designated health information exchange. Ms Lyons reported receiving grants from the Bureau of Justice Assistance, US Department of Justice, during the conduct of the study. Dr Weiner reported receiving grants from the US Department of Justice to the Maryland Department of Health during the conduct of the study. No other disclosures were reported.

Purpose To determine the frequency and characteristics of safety advisories issued by medicines regulatory agencies in Australia, Canada, United Kingdom (UK) and the United States (US). Methods This retrospective analysis examines medicines safety warnings issued by the US Food and Drug Administration (FDA), Health Canada (HC), the Australian Therapeutic Goods Administration (TGA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA) from January 1, 2007 until December 31, 2016. A database of warnings obtained from regulators' websites was developed and warnings were classified by communication type, drug, or therapeutic class focus, and the risk discussed. Advisories identifying the same drug or therapeutic class and risk were combined into groups termed “drug‐risk issues” for comparisons between regulators. Results Over this 10‐year period, 1441 advisories were identified, with the MHRA issuing the most advisories (MHRA = 469, FDA = 382, HC = 370 TGA = 220). Seventy two percent focussed on single drugs (1034/1441) and 58.7% were alerts (846/1441) posted on the regulators' websites. Diabetes drugs, smoking cessation drugs and immunomodulatory agents were the individual drug types most often subject to safety advisories, while antidepressants, antipsychotics, and proton‐pump inhibitors were the top three therapeutic classes. Of 680 identified drug‐risk issues, 3.8% (26/680) described a risk of death. By body system, cardiac effects were the most frequent: 10.4% (71/680). Conclusion We found considerable differences in the use of advisories including frequency, communication type, and focus. Disparities in communication about emergent evidence on risks may mean that clinicians and patients in some countries are less well informed about medicine safety concerns than others.

Purpose There has been less attention to the transparency of postmarket evidence of harmful effects of medicines than of premarket clinical trial data. This is a case study of requests for Australian “direct health professional communications” (DHPCs). These letters are used by regulators and manufacturers to inform clinicians of emergent evidence of harm. DHPCs are not made public by Australia's Therapeutic Goods Administration (TGA). Methods We requested all DHPCs sent out in Australia from 2007 to 2016 inclusive for 207 drugs that were subject to safety advisories over this decade in Canada, the United Kingdom, and/or the United States. We contacted 39 manufacturers (February to May 2018), with repeat requests to nonrespondents, and a follow‐up freedom‐of‐information (FOI) request to the TGA. Results Fifteen companies provided information, either sending DHPCs (n = 4, on five drugs) or affirming none were sent out (n = 11). The remaining 24 of 39 (62%) companies did not provide DHPCs: nine (23%) refused the request, often citing commercial confidentiality; the rest provided no answer despite repeat requests. In total, we had no information for 170 of 207 (82%) of the drugs. Our FOI request to the TGA was unsuccessful. Conclusions Our experience highlights unacceptable secrecy concerning safety warnings previously sent to thousands of Australian clinicians. In the absence of explicit regulatory policy supporting disclosure, companies differed in their response. These letters warn of serious and often life‐threatening harm and guide safer care; full ongoing public access is needed, ideally in searchable online databases.

ObjectiveTo evaluate the association between regulatory drug safety advisories and changes in drug utilisation.DesignWe conducted controlled, interrupted times series analyses with administrative prescription claims data to estimate changes in drug utilisation following advisories. We used random-effects meta-analysis with inverse-variance weighting to estimate the average postadvisory change in drug utilisation across advisories.Study populationWe included advisories issued in Canada, Denmark, the UK and the USA during 2009–2015, mainly concerning drugs in common use in primary care. We excluded advisories related to over-the-counter drugs, drug-drug interactions, vaccines, drugs used primarily in hospital and advisories with co-interventions within ±6 months.Main outcome measuresChange in drug utilisation, defined as actual versus predicted percentage change in the number of prescriptions (for advisories without dose-related advice), or in the number of defined daily doses (for dose-related advisories), per 100 000 population.ResultsAmong advisories without dose-related advice (n=20), the average change in drug utilisation was −5.83% (95% CI −10.93 to –0.73; p=0.03). Advisories with dose-related advice (n=4) were not associated with a statistically significant change in drug utilisation (−1.93%; 95% CI −17.10 to 13.23; p=0.80). In a post hoc subgroup analysis of advisories without dose-related advice, we observed no statistically significant difference between the change in drug utilisation following advisories with explicit prescribing advice, such as a recommendation to consider the risk of a drug when prescribing, and the change in drug utilisation following advisories without such advice.ConclusionsAmong safety advisories issued on a wide range of drugs during 2009–2015 in 4 countries (Canada, Denmark, the UK and the USA), the association of advisories with changes in drug utilisation was variable, and the average association was modest.

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