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

Comprehensibility of Contraindications in German, UK and US Summaries of Product Characteristics/Prescribing Information—A Comparative Qualitative and Quantitative Analysis

Contraindications (CIs) in Summaries of Product Characteristics (SmPCs)/Prescribing Information (PI) that lack clarity may pose a risk to medication safety and increase the risk for adverse drug reactions. We assessed and compared SmPCs/PI from three major drug markets regarding comprehensibility from the prescriber perspective, as well as usability in clinical decision support systems. 158 drugs met the following inclusion criteria: marketed in Germany (DE), United Kingdom (UK) and United States (US) and belonged to the 100 most recently FDA approved and/or 100 most frequently prescribed drugs in either country. In the 474 (3 × 158) SmPCs/PI all expressions for absolute CIs were identified, divided into 3999 stand-alone terms and evaluated according to ‘clarity’ and ‘codability’. The average number of absolute CIs per drug differed drastically between the three markets (DE: 11.7, UK: 9.0, US: 4.6). Expressions were frequently unclear (DE: 27.2% (95% CI 25.2–29.2%), UK: 28.5% (26.2–30.9%), US: 22.6% (19.7–25.8%)). Moreover, 60.9% (58.6–63.1%), 63.6% (61.0–66.0%), and 64.7% (61.2–68.1%) of the expressions were not codable in DE, UK, and US, respectively. Taken together, in three major drug markets, statements regarding CIs in SmPCs/PI substantially differ in frequency and frequently lack clarity and codability which poses an unnecessary obstacle to medication safety.

Evolving patterns of antiretroviral drug interactions in people living with HIV in British Columbia, Canada

OBJECTIVES

To characterize the annual prevalence of antiretroviral/non-antiretroviral drug interactions (DIs) in relation to antiretroviral therapy (ART) prescribing patterns, and to describe DI-related ART changes.

DESIGN/METHODS

This cohort study included ART-treated adults in British Columbia, Canada between 01-Jan-2010 and 31-Dec-2016. Medication dispensing records were abstracted from a population-based, linked administrative-health dataset and used to identify antiretroviral-comedication DIs ("caution"/"avoid" DIs in HIV-focused DI-checkers). We identified temporal trends in annual DI prevalence and quantified the association between taking higher DI-risk ART and receiving non-recommended antiretroviral-comedication combinations using Poisson regression models, modified for binary outcomes and correlated data. Clinician-reported, DI-related ART changes and associated adverse events were abstracted from an HIV drug treatment registry and summarized descriptively.

RESULTS

Among 8571 ART-treated adults who received non-antiretroviral comedications, prevalence of having any DI or receiving non-recommended drug combination(s) significantly declined from 85% to 71% and 5.6% to 3.2%, respectively, between 2010 and 2016 (p < 0.001). This paralleled a shift from higher DI-risk ART (e.g. ritonavir/cobicistat-boosted protease inhibitors) to lower DI-risk ART (e.g. unboosted integrase inhibitors). Risk of receiving a non-recommended antiretroviral-comedication combination was greater for persons taking higher versus lower DI-risk ART (aRR 3.12, 95%CI 2.24-4.35). Boosted antiretroviral-inhaled corticosteroid DIs accounted for the most commonly dispensed, non-recommended drug combinations, and the most commonly reported DI-related adverse events (adrenal insufficiency).

CONCLUSION

The prevalence of antiretroviral-comedication DIs is declining as ART shifts towards antiretrovirals with lower DI potential, but non-recommended drug combinations remain a concern. Healthcare providers should screen for DIs whenever drugs are prescribed or dispensed.

The challenge of HIV treatment in an era of polypharmacy

INTRODUCTION

The availability of potent antiretroviral therapy has transformed HIV infection into a chronic disease such that people living with HIV (PLWH) have a near normal life expectancy. However, there are continuing challenges in managing HIV infection, particularly in older patients, who often experience age-related comorbidities resulting in complex polypharmacy and an increased risk for drug-drug interactions. Furthermore, age-related physiological changes may affect the pharmacokinetics and pharmacodynamics of both antiretrovirals and comedications thereby predisposing elderly to adverse drug reactions. This review provides an overview of the therapeutic challenges when treating elderly PLWH (i.e. >65 years). Particular emphasis is placed on drug-drug interactions and other common prescribing issues (i.e. inappropriate drug use, prescribing cascade, drug-disease interaction) encountered in elderly PLWH.

DISCUSSION

Prescribing issues are common in elderly PLWH due to the presence of age-related comorbidities, organ dysfunction and physiological changes leading to a higher risk for drug-drug interactions, drugs dosage errors and inappropriate drug use.

CONCLUSIONS

The high prevalence of prescribing issues in elderly PLWH highlights the need for ongoing education on prescribing principles and the optimal management of individual patients. The knowledge of adverse health outcomes associated with polypharmacy and inappropriate prescribing should ensure that there are interventions to prevent harm including medication reconciliation, medication review and medication prioritization according to the risks/benefits for each patient.

Development of a new Japanese guideline on drug interaction for drug development and appropriate provision of information

Drug interactions, in particular with concomitant drugs having a narrow therapeutic range, sometimes cause serious adverse drug reactions or attenuation of the therapeutic effect. Therefore, evaluation of the characteristics and severities of possible drug interactions in drug development is essential to understand such interactions to help prevent any potential risk for patients. In Japan, a regulatory document which was notified in 2001 to outline the basic principles of drug interaction studies during drug development was revised as a new guideline after 17 years to present general procedures that are currently considered scientifically valid. This article aims to present an overview of development process of the new Japanese guideline for investigating drug interactions and show the impact of implementating this guideline on drug interaction evaluations, thereby providing future perspectives of regulatory activities on drug interactions.

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.

Signal detection of human papillomavirus vaccines using the Korea Adverse Events Reporting System database, between 2005 and 2016

Background Adverse events (AEs) not listed on drug labels have recently been reported in young girls vaccinated against HPV, but signal detection related to the human papillomavirus (HPV) vaccine has never been conducted in South Korea using the Korea Adverse Event Reporting System database of Korea Institute of Drug Safety & Risk Management at Ministry of Food and Drug Safety. Objective To analyze signals associated with HPV vaccines using the Korean spontaneous AEs reporting system and data-mining methods and compare the results to current vaccine label information in South Korea and the United States of America, United Kingdom, European Union, and Japan to detect signals not currently listed on the labels. Setting We evaluated the Korea Institute of Drug Safety & Risk Management database from January 2005 to December 2016. After pre-screening the data, the adjusted total numbers of HPV-related AE reports and AEs were 2566 and 4748 and those of all other vaccine-related AE reports and AEs were 21,878 and 120,688, respectively. Methods Three data mining algorithms (proportional reporting ratio, reporting odds ratio and information component) were used to assess AEs. A signal was defined when the criteria for all three indicators were satisfied. The detected signals were compared to the label information of HPV vaccines from South Korea, the United States of America, United Kingdom, European Union, and Japan. Main outcome measure Signals of AE after HPV vaccination, which met all three data mining indices. Results In this study, we found a total 97 signals of AE after HPV vaccination. Of these, 78 AEs were already present on the HPV vaccine labels of South Korea and the following 19 AEs were not listed: neuralgia, tremor, neuritis, depersonalization, axillary pain, personality disorder, increased salivation, peptic ulcer, circulatory failure, hypotension, peripheral ischemia, cerebral hemorrhage, micturition disorder, facial edema, ovarian cyst, weight increase, pain anxiety, oral edema, and back pain. Moreover, AE information on the current HPV vaccine labels of South Korea, the United States of America, United Kingdom, European Union, and Japan was inconsistent. When comparing the 19 AE signals that were not listed on the drug label in South Korea with the labels from the other countries, neuritis, axillary pain, cerebral hemorrhage, facial edema, pain anxiety, and back pain appreared on the U.S. Food and Drug Administration HPV vaccine labels but not on the United Kingdom labels, and hypotension was listed only on labels in the European Union and Japan. Conclusions South Korea should develop a system for proactively updating HPV labels. These results also suggest potential research directions such as vaccination label expansion, pharmacovigilance studies, and identification of causality in AEs associated with HPV vaccination.