Speaking the same language? International variations in the safety information accompanying top-selling prescription drugs

Warning Labels as a Public Health Intervention: Effects and Challenges for Tobacco, Cannabis, and Opioid Medications

Warning labels help consumers understand product risks, enabling informed decisions. Since the 1966 introduction of cigarette warning labels in the United States, research has determined the most effective message content (health effects information) and format (brand-free packaging with pictures). However, new challenges have emerged. This article reviews the current state of tobacco warning labels in the United States, where legal battles have stalled pictorial cigarette warnings and new products such as electronic cigarettes and synthetic nicotine products pose unknown health risks. This article describes the emerging research on cannabis warnings; as more places legalize recreational cannabis, they are adopting lessons from tobacco warnings. However, its uncertain legal status and widespread underestimation of harms impede strict warning standards. The article also reviews opioid medication warning labels, suggesting that lessons from tobacco could help in the development of effective and culturally appropriate FDA-compliant opioid warning labels that promote safe medication use and increased co-dispensing of naloxone.

Improving drug safety with adverse event detection using natural language processing

INTRODUCTION

Pharmacovigilance (PV) involves monitoring and aggregating adverse event information from a variety of data sources, including health records, biomedical literature, spontaneous adverse event reports, product labels, and patient-generated content like social media posts, but the most pertinent details in these sources are typically available in narrative free-text formats. Natural language processing (NLP) techniques can be used to extract clinically relevant information from PV texts to inform decision-making.

AREAS COVERED

We conducted a non-systematic literature review by querying the PubMed database to examine the uses of NLP in drug safety and distilled the findings to present our expert opinion on the topic.

EXPERT OPINION

New NLP techniques and approaches continue to be applied for drug safety use cases; however, systems that are fully deployed and in use in a clinical environment remain vanishingly rare. To see high-performing NLP techniques implemented in the real setting will require long-term engagement with end users and other stakeholders and revised workflows in fully formulated business plans for the targeted use cases. Additionally, we found little to no evidence of extracted information placed into standardized data models, which should be a way to make implementations more portable and adaptable.

Safety-Related Drug Label Changes Following Large Post-Marketing Cardiometabolic Trials: A Review of European Public Assessment Reports

Selective safety data collection may simplify late-stage clinical trials and improve their feasibility. However, the impact on increasing overall drug safety knowledge is unknown. The aim of this study is to evaluate how much safety information is added to the drug label based on large trials after initial authorization. Changes made to the "undesirable effects" section of the drug label of cardiometabolic agents approved between 2000 and 2020 based on the results of large (> 1,000 patient) clinical trials submitted to the European Medicines Agency (EMA) were evaluated. The study focused on glucose lowering, antithrombotic, and lipid-modifying agents. The primary outcome was the number of changes in adverse drug reactions in the drug label. The EMA reviewed 55 large trials concerning 25 cardiometabolic agents after the initial marketing authorization, which included 402,444 patients. Ultimately, 38 trials (69%) resulted in a safety section update, whereas 17 trials (31%) did not. Changes in listed adverse drug reactions were made following 19 trials (35%) for 12 agents: 77 adverse drug reactions were added, 11 were deleted, and the frequencies of 43 were changed. Most changes in adverse drug reactions arose from trials with antithrombotic agents (88%) and trials performed in a new population (92%). Large trials for cardiometabolic agents reported after authorization add limited new safety information on adverse drug reactions, especially when performed in the population studied prior to approval. This suggests that selective safety data collection does not reduce learnings from late stage cardiometabolic trials in populations comprehensively studied before.

Regulatory authority and clinical acceptability: Physicians' responses to regulatory drug safety warnings

AIM

Medicines regulators issue post-market safety warnings to advise of newly uncovered risks, but with mixed impacts. We aimed to identify factors influencing the use of regulatory warnings by primary care and specialist physicians in the US and Australia.

METHODS

Semi-structured qualitative interviews with 40 primary care physicians, endocrinologists, and other generalist specialists in Boston USA and Australia. Coding and analysis were carried out inductively and iteratively to identify and examine key factors. Analysis centred around four areas; physicians' awareness of drug safety information, preferred information sources, opinion-forming, and sharing of information with patients.

RESULTS

Uncertainty, trust, and clinical authority emerged as factors influencing use of advisories. Although regulators were trusted as authoritative institutions, they appeared to lack clinical authority, and physicians validated regulatory information against other trusted sources including evidence, expert opinion, and experience. Specialists became aware of drug safety issues through specialised literature, using evidence and clinical consensus to form opinions. Primary care physicians, fielding high volumes of information, relied on convenient, accessible information sources including the media and the 'clinical grapevine' for awareness, and on clinical colleagues, specialists, and experience for interpretation. Communicating risk to patients was complicated by uncertainty; physicians tailored information to patients' health literacy and information needs. US physicians were more aware of their national regulator's post-market safety role than Australian physicians of theirs.

CONCLUSION

Drug safety warnings may not be optimally received or used. Regulators should consider strategies that increase trust, clinical relevance, and accessibility, and address physicians' needs in communicating risk to patients.

Regulatory Safety Learning Driven by the Mechanism of Action: The Case of TNF-α Inhibitors

The summary of product characteristics (SmPCs) is an important information source that includes the adverse drug reactions (ADRs) associated with the drug. Drugs with the same mechanism of action are expected to have a similar ADR profile and thus a substantial overlap of the described ADRs in the SmPC. The objective of this study is to assess this overlap. We extracted all ADRs (excluding hypersensitivity and administration site reactions) that were described in the first and all subsequent versions of the SmPCs of all approved TNF-α inhibitors in the European Union. The Medical Dictionary for Regulatory Activities was used to characterize the ADRs. At the end of follow-up, 293 unique ADRs (at high level term level) were described in the SmPCs of the 5 TNF-α inhibitors. There was substantial variation in the number of ADRs described in the SmPC among the TNF-α inhibitors. Of the 293 ADRs, 133 (45%) were described in the SmPC of one TNF-α inhibitor and 39 (13%) in the SmPCs of all 5 TNF-α inhibitors. Serious ADRs and ADRs classified as important risks were described approximately four times more often in a second SmPC than ADRs not classified as such. In conclusion, the ADRs described in the SmPCs of the TNF-α inhibitors differ considerably in number and type. In order to adequately inform prescribers and patients, acquired knowledge of the safety profile of drugs with the same mechanism of action should increasingly be taken into account in the assessment of all drugs within the class.

International Coherence of Pediatric Drug Labeling for Drug Safety: Comparison of Approved Labels in Korea and the United States

The objective of this study was to analyze information on pediatric use in Korean drug product labels and compare it with that in US Food and Drug Administration (FDA) labeling information. Prescription information on pediatric use contained in the commonly used drugs’ product labels approved by Korean government was compared with that approved by the FDA. Among the top 50 commonly prescribed drugs, 20 drugs were deemed to have insufficient prescribing information in Korean drug labels. Pediatric prescribing information regarding indication, approved age, formulations, and safety was insufficient in Korean drug labels compared with those in the FDA. Most important, the adverse events frequently reported in Korean children were not sufficiently presented in drug labels. In conclusion, this study highlights the urgent need for the Korean regulatory agency to encourage and accelerate research and development to increase the extent of pediatric prescribing information to be added to drug labels to promote appropriate drug prescribing for children.

Jurisdictional Guidance on DOAC Use-Will It Affect Practice? A Comparison of European, American, and Canadian Product Monographs

Objective: To identify clinically relevant areas of concordance and discordance between product monographs for 4 direct oral anticoagulants (DOACs) approved by regulatory authorities in Europe, the United States, and Canada. Data Sources: For each DOAC (apixaban, dabigatran, edoxaban, rivaroxaban), manufacturer product monographs were retrieved from the European Medicines Database, US Food and Drug Administration, and Health Canada Drug Product Database. Data Extraction: Monographs for each DOAC were independently reviewed by 2 investigators to identify areas of concordance and discordance. Discordance existed if it was deemed that a potentially clinically relevant difference existed. A heat map summarizing the data was created to identify areas of complete concordance, partial concordance (concordance between 2 of 3 monographs), and complete discordance. Data Synthesis: The areas of concordance were indications for use, use in extremes of weight, and switching to/from the DOAC. Areas of discordance included the following: differing recommendations for use/dosing with renal dysfunction; contraindication or use with caution with drug interactions, pregnancy, and hepatic/renal dysfunction; and timing of DOAC with spinal/epidural anesthesia after a procedure or traumatic puncture. Relevance to Patient Care and Clinical Practice: Concordance was most evident for uncomplicated patients with atrial fibrillation or venous thromboembolism, whereas discordance emerged for those having characteristics/factors wherein clinicians may seek clarification within product monographs (eg, impaired renal/hepatic function, drug interactions). As such, clinicians must be familiar with product information within their country of practice. Conclusion: Variability between jurisdictions was evident, and variability of DOAC use is likely to increase with expanding worldwide uptake.

Development and evaluation of user-tested Thai patient information leaflets for non-steroidal anti-inflammatory drugs: Effect on patients' knowledge

INTRODUCTION

Thai patients do not routinely receive patient information leaflets (PILs) with medicines, so awareness of safety issues is low. This study aimed: i) to develop Thai PILs for NSAIDs and subject these to user-testing, and ii) to assess the potential value of PILs from the patient perspective and effect on patient knowledge.

METHODS

Four PILs for NSAIDs were developed and subjected to multiple rounds of user-testing by the general public. Self-administered questionnaires were distributed to orthopaedic out-patients prescribed one of these NSAIDs, assessing knowledge before and after providing a PIL. The follow-up questionnaire also sought use of and views on the PILs using a visual analogue scale (VAS).

RESULTS

1,240 baseline questionnaires were completed; only 13.5% of patients had good knowledge. 688 patients returned follow-up questionnaires (55.5%), of whom75% had good knowledge. In patients completing both questionnaires, mean knowledge score increased from 6.22±1.40 to 8.42±1.41 (p<0.001). Patients with high educational levels had high baseline scores (OR = 2.728) and showed greatest improvement in knowledge (OR = 5.628). 90% (625) of follow-up respondents indicated they read all information in the PILs. All also agreed that these PILs should distributed to all patients taking NSAIDs. The median VAS score for usefulness was 9.3 (IQR 8.6-10.0).

CONCLUSIONS

User-testing of PILs was feasible in a Thai population and enabled the development of acceptable and desirable PILs. PILs could improve patients' knowledge about their medicine, particularly among those with higher educational level. User-tested PILS could meet the need for more written medicine information.

Consistency of listed indications and contraindications between the U.S., the U.K., Japan, and Korea on prescription drug labels

Inclusion of indications and contraindications in drug labeling is essential for drug approval. Little is known regarding how well new drug information labels agree across countries. To compare the number of indications and contraindications on the labels of drugs in the U.S., U.K., Japan, and Korea, we selected 81 new drugs approved in these countries between 2008 and 2016 and assessed the number of indications and contraindications on each label. Average and median numbers with standard deviations were presented for the 81-drug set, and for subsets grouped according to drug class. Correlation analyses were conducted to estimate Pearson and concordance correlation coefficients. No significant difference was observed across countries in the number of indications, the average being 1.69, 1.67, 1.54, and 1.51 in the U.S., the U.K., Korea, and Japan (p = 0.31), respectively. By contrast, substantial variation was observed in the number of contraindications, the average being 1.54, 2.42, 3.53, and 3.00 in the U.S., the U.K., Korea, and Japan (p < 0.001), respectively. Pearson correlation coefficients comparing contraindications were 0.40, 0.48, and 0.47 for U.S.-U.K., U.S.-Korea, and U.S.-Japan, but 0.83, 0.73, and 0.71 for U.K.-Korea, U.K.-Japan, and Korea-Japan, respectively (p < 0.01). There is consistency in the number of indications, but a substantial discrepancy in contraindications listed in drug labeling across countries. Further study is warranted to improve global harmonization of contraindication listings.

Assessment of Consistency of Drug Interaction Information in Drug Labels Among the United States, the United Kingdom, China, Japan, and Korea

Information gap in drug labeling among countries create challenges in therapeutic use of drugs. We aimed to evaluate the consistency of drug interaction information in drug labels among five countries. The study drugs were chosen from the commonly approved drug list in the US, UK, China, Japan, and Korea. The degree of agreement of drug interaction data was evaluated by kappa coefficient. Thirty-eight drugs were evaluated, and moderate degree of agreement was observed among all countries' labeling (κ = 0.43, 95% confidence interval (CI) = 0.41-0.46). The degree of agreement was the highest for the UK and Korea (κ = 0.71, 95% CI = 0.67-0.75) and the lowest for the UK and Japan (κ = 0.02, 95% CI = 0.00-0.04). Information regarding drug interactions listed in the studied drug labels was not in high agreement. International standardization of drug labeling is required to ensure safe drug therapy.

Transnational pharmacogovernance: emergent patterns in the jazz of pharmaceutical policy convergence

BACKGROUND

As a transnational policy network, the International Council for Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) aligns international regulatory standards to address the pressures of globalization on the pharmaceutical industry and increase access to new medicines. Founding ICH members include regulators and pharmaceutical industry trade associations in the European Union, the United States and Japan. In this paper we explore the manner in which state interdependence fosters the conditions for regulatory harmonization by tracing the underlying parallels between ICH and member state pharmacogovernance to clarify emergent patterns in regulatory policy convergence.

RESULTS

A shift to the life cycle approach to pharmaceutical regulation corresponded with international convergence in pre-market standards as emphasis shifted to post-market standards where convergence remains unresolved. Transnational pharmacogovernance was found to concentrate regulatory authority within a co-regulatory model of bilateral negotiation with pharmaceutical trade associations in defining safety and efficacy standards. Given a context of state interdependence, parallels were found between transnational and ICH member pharmacogovernance modes that guide policy development. Divergent modes of state regulatory governance that re-calibrate perceptions of risk and risk mitigation were found to coincide with post-market policy dissonance.

CONCLUSION

Although interdependence fostered harmonization in pre-market standards and aligned with increased focus on post-market approaches, the confluence of divergent state governance modes and perceptions of risk may inspire improvisation in post-market standards. As the ICH expands to an ensemble with a greater global reach, further research is needed to clarify the manner in which interdependence shapes transnational pharmacogovernance and the conditions that foster policy convergence in the public interest.

Searching online to buy commonly prescribed psychiatric drugs

The use of online pharmacies to purchase prescription drugs is increasing. The patient experience when searching to buy commonly prescribed psychiatric drugs was investigated. Using the search term "buy [drug name] online" in Google, 38 frequently prescribed drugs, including 13 with a high potential for abuse, were searched by brand and generic names. The first page of results were analyzed, including with pharmacy certification checkers and ICANN WHOIS. Search results for all drugs yielded 167 pharmacies, of which 147 (88%) did not require a prescription. Considering all searches, the average number of pharmacies requiring a prescription was 2.7 for a brand name drug and 2.4 for a generic name. A phrase like "buy without a prescription" usually appeared on the search results page. All results for drugs with a high potential for abuse were for illegal pharmacies. Information from certification agencies was often conflicting. Most pharmacies were registered internationally. Patients searching online to purchase prescription psychiatric drugs are presented predominantly with illegal pharmacies, and find conflicting certification data. Patient education should address typical search results. Societal pressures may increase the use of online pharmacies including prescription drug costs, stigma, loss of trust in expert opinion, and the changing patient role.

ADHD medications and cardiovascular adverse events in children and adolescents: cross-national comparison of risk communication in drug labeling

PURPOSE

Regulators approve written medical information for healthcare professionals and consumers, but the consistency of these sources has not been studied. We investigated the consistency of information regarding four cardiovascular risks of attention-deficit/hyperactivity disorder (ADHD) medications approved in four countries.

METHODS

Professional and consumer product labeling for five ADHD medications approved in Australia, Canada, the UK, and the USA were obtained in March/April 2016. Language describing the relationship between medication and elevated blood pressure and/or heart rate, myocardial infarction, stroke, and sudden death was extracted verbatim and classified into one of four categories based on the described relationship between medication and adverse event: "confirmed," "unconfirmed," "mixed," and "not mentioned." We judged the consistency of messages delivered to healthcare professionals and consumers as either "consistent" or "inconsistent."

RESULTS

We obtained 20 healthcare professional labels and 20 corresponding consumer labels for the five ADHD medications registered in all four countries. Not all professional and consumer labeling contained language regarding all four adverse events. Of the 80 theoretically evaluable drug-risk pairs, 38 (48%) were not evaluable because of absence of mention of the adverse event in the consumer label. For the remaining 42, the potential causal relationship was expressed consistently in professional and consumer labeling in 25 (60%) cases. The cardiovascular risk profile was not described consistently across all four countries for any of the five drugs.

CONCLUSIONS

Product labeling provides healthcare professionals and consumers with inconsistent messages regarding the potential causal relationship between stimulant use and specific cardiovascular risks in children and adolescents. Copyright © 2017 John Wiley & Sons, Ltd.

Differences between the United States and Japan in labels of oncological drugs

PURPOSE

Our study addresses how the information in the labels differed between United States (US) and Japan, what factors were associated with the decision to place the boxed warning on the label, and the relation of both countries in terms of drug label policy.

METHODS

We investigated adverse drug reactions (ADRs) in boxed warnings for 44 oncological drug labels approved from 2004 to 2014 in both Japan and the US. We applied conditional logistic regression to examine how likely it was for each ADR to be included in a boxed warning.

RESULTS

There were substantial differences in all sections of the labels. The concordance rate between US and Japanese labels was 44.1% for serious adverse reactions and 30.5% for boxed warnings. Our regression analysis indicated that deaths and/or terminations related to specific ADRs reported in clinical trials were significantly associated with inclusion of the ADR in boxed warnings in Japan, but not in the US. The boxed warnings of similar drugs seemed to affect those of follow-on drugs in both countries. US drug labels were likely to influence Japanese labels, but not vice versa.

CONCLUSION

This study suggests that the observed differences are not solely due to differences in clinical outcomes between the two countries, but rather due to differences in regulatory considerations and historical factors in both local and global contexts. Further research is needed to examine the impact of these differences on public health and to determine how and to what extent we should intervene with this status quo. Copyright © 2016 John Wiley & Sons, Ltd.

Variation in adverse drug reactions listed in product information for antidepressants and anticonvulsants, between the USA and Europe: a comparison review of paired regulatory documents

OBJECTIVE

To compare consistency of adverse drug reaction (ADR) data in publicly available product information documents for brand drugs, between the USA and Europe. To assess the usefulness of information for prescribers and patients.

DESIGN

A comparison review of product information documents for antidepressants and anticonvulsants concurrently marketed by the same pharmaceutical company in the USA and Europe.

SETTING

For each drug, data were extracted from the US Product Inserts and the European Summary of Product Characteristics documents between 09/2013 and 01/2015.

PARTICIPANTS

Individuals contributing ADR information to product information documents.

MAIN OUTCOMES MEASURES

All ADRs reported in product information sections 5 and 6 (USA), and 4·4 and 4·8 (Europe).

RESULTS

Twelve brand drugs--24 paired documents--were included. On average, there were 77 more ADRs reported in the USA compared with in the European product information document, with a median number of 201 ADRs (range: 65-425) and 114 (range: 56-265), respectively. More product information documents in the USA reported information on the source of evidence (10 vs 5) and risk (9 vs 5) for greater than 80% of ADRs included in the document. There was negligible information included regarding duration, severity, reversibility or recurrence of ADRs. On average, only 29% of ADR terms were reported in both paired documents.

CONCLUSIONS

Product information documents contained a large number of ADRs, but lacked contextual data and information important to patients and prescribers, such as duration, severity and reversibility. The ADR profile was found to be inconsistently reported between the USA and Europe, for the same drug. Identifying, selecting, summarising and presenting multidimensional harm data should be underpinned by practical evidence-based guidelines. In order for prescribers to provide considered risk-benefit advice across competing drug therapies to patients, they need access to comprehensible and reliable ADR information.

Medicine information leaflets for non-steroidal anti-inflammatory drugs in Thailand

BACKGROUND

The importance of promoting the use of patient-oriented medicines leaflets is recognized in many countries. Leaflets should include basic information plus specific warnings, and be provided with all medicines, but there is little attempt at enforcement of these requirements in Thailand.

OBJECTIVE

To determine content and availability of Thai information leaflets for nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

Leaflets for all NSAIDs available for purchase from 34 pharmacies in a large city were evaluated against a checklist and number of leaflets assessed against number of medicine packs available in each pharmacy.

RESULTS

Of the 76 leaflets for ten different NSAIDs, 67 (88 %) were for locally manufactured products. Only 22 % of 76 leaflets were sufficient in number for distribution with medicines, while only 4 % had patient-oriented leaflets. No leaflet covered all topics in the checklist. Less than half included safety information, such as contraindications (46 %), precautions (47 %), and adverse drug reactions (34 %). Locally-produced leaflets provided less information than those for originator products and no leaflet included all the warnings required by Thai regulations.

CONCLUSION

This study illustrates the variable availability and quality of NSAID information leaflets. The lack of accessible essential information about medicines in Thailand requires urgent attention to enable patients to minimise adverse reactions.

Comparison of pregnancy and lactation labeling for attention-deficit hyperactivity disorder drugs marketed in Australia, the USA, Denmark, and the UK

BACKGROUND

Pregnancy and lactation labeling is presented in the officially recognized product information (PI) accompanying prescription drugs to ensure appropriate prescribing in pregnant and breastfeeding women.

OBJECTIVE

The aim of this study was to analyze pregnancy and lactation labeling in PI for attention-deficit hyperactivity disorder drugs marketed across countries and to compare this information with respect to consistency and discrepancy.

METHODS

We manually surveyed PI for atomoxetine, methylphenidate, and modafinil marketed by the same pharmaceutical companies in Australia, the USA, Denmark, and the UK. We extracted information regarding data sources (animal and human data), risk to the fetus or breastfed child, excretion in breast milk, and recommendations for use. The extracted information was then analyzed and compared with respect to consistency and discrepancy.

RESULTS

Inter-country discrepancies were identified with respect to both animal and human data sources presented, types of risks listed in association with exposure during pregnancy and lactation, information regarding excretion of the drug in breast milk, and recommendations for use. Consistency was identified between PI for drugs marketed in the EU.

CONCLUSION

The study suggests that pregnancy and lactation labeling in PI for drugs marketed by the same pharmaceutical companies depend on the country of marketing; this raises concern about the reliability of PI documents as a useful source of information for appropriate prescribing during pregnancy and lactation. Discrepancies in this information can potentially lead to inappropriate prescribing in pregnant and breastfeeding women, who may expose their fetuses and breastfed children to unnecessary risks. At the same time, unjustified warnings against breastfeeding may result in children being unnecessarily weaned from being breastfed.

Computational investigations of hERG channel blockers: New insights and current predictive models

Identification of potential human Ether-a-go-go Related-Gene (hERG) potassium channel blockers is an essential part of the drug development and drug safety process in pharmaceutical industries or academic drug discovery centers, as they may lead to drug-induced QT prolongation, arrhythmia and Torsade de Pointes. Recent reports also suggest starting to address such issues at the hit selection stage. In order to prioritize molecules during the early drug discovery phase and to reduce the risk of drug attrition due to cardiotoxicity during pre-clinical and clinical stages, computational approaches have been developed to predict the potential hERG blockage of new drug candidates. In this review, we will describe the current in silico methods developed and applied to predict and to understand the mechanism of actions of hERG blockers, including ligand-based and structure-based approaches. We then discuss ongoing research on other ion channels and hERG polymorphism susceptible to be involved in LQTS and how systemic approaches can help in the drug safety decision.

Inconsistencies and misleading information in officially approved prescribing information from three major drug markets

The summary of product characteristics (SPC) should provide information for the safe prescription and use of a drug. We evaluated the consistency of critical interaction warnings, the quality of presentation of undesirable effects as well as concordance of critical information of representative drugs marketed in the United States, the UK, and Germany. Reciprocal warnings regarding drug-drug interactions that constitute contraindications were frequently missing in the SPCs of the drugs concerned (all countries >40%). Most SPCs did not explicitly exclude adverse reactions considered not reasonably attributable to the use of the drug. Comparing SPCs of different generic brands of the same drug, only 60, 10, and 20% of the US, UK, and German SPCs, respectively, provided identical contraindications. Current SPCs contain inconsistencies and misleading data that are not compatible with the purpose of SPCs, which is to provide a basis for the safe prescription and use of drugs.

Discrepancies in listed adverse drug reactions in pharmaceutical product information supplied by the regulatory authorities in Denmark and the USA

Pharmaceutical product information (PI) supplied by the regulatory authorities serves as a source of information on safe and effective use of drugs. The objectives of this study were to qualitatively and quantitatively compare PIs for selected drugs marketed in both Denmark and the USA with respect to consistency and discrepancy of listed adverse drug reaction (ADR) information. We compared individual ADRs listed in PIs from Denmark and the USA with respect to type and frequency. Consistency was defined as match of ADRs and of ADR frequency or match could not be ruled out. Discrepancies were defined as ADRs listed only in one country or listed with different frequencies. We analyzed PIs for 40 separate drugs from ten therapeutic groups and assigned the 4003 identified ADRs to System Organ Classes (Medical Dictionary for Regulatory Activities [MedDRA] terminology). Less than half of listed ADRs (n = 1874; 47%) showed consistency. Discrepancies (n = 2129; 53%) were split into ADRs listed only in the USA (n = 1558; 39%), ADRs listed only in Denmark (n = 325; 8%) and ADRs listed with different frequencies (n = 246; 6%). The majority of listed ADRs were of the type “gastrointestinal disorders” and “nervous system disorders”. Our results show great differences in PIs for drugs approved in both Denmark and the USA illuminating concerns about the credibility of the publicly available PIs. The results also represent an argument for further harmonization across borders to improve consistency between authority-supplied information.