Vestibular disorders following BNT162b2 mRNA COVID-19 vaccination: A retrospective case series.

BACKGROUND: There are few publications regarding manifestations of vestibular disorders (VDs) following BNT162b2 mRNA COVID-19 vaccination. PURPOSE: We describe cases of VD potentially related to BNT162b2 vaccination and calculate its reporting rate, in order to enlarge knowledge about this adverse effect. METHODS: A retrospective analysis of cases of VD following BNT162b2 vaccination reported to the pharmacovigilance centre of Georges-Pompidou European Hospital (France), in 2021 was performed. In order to identify these cases from the pharmacovigilance database containing all our registered cases, we used the Standardised MedDRA Query (SMQ) 'vestibular disorders'. Then we analysed cases with vestibular symptoms, based on the association of typical manifestations. The reporting rate was calculated based on the number of VD cases and the number of vaccinated patients. RESULTS: Among 6608 cases reported to our centre related to COVID-19 vaccines during 2021, 34 VDs associated with BNT162b2 administration were included. They were mainly reported in females (79%), 62% occurred after the first dose and 32% were serious. Symptoms had completely resolved in 13 cases (38%). Vertigo was the most common symptom followed by balance disorders. Three patients received second dose without reappearance of VD. The final diagnosis was reported in 10 patients (six cases of vestibular neuritis, two cases of central VD, two cases of benign paroxysmal positional vertigo). The regional reporting rate was 26 [95% CI: 17-34] cases of VD per 1 million persons vaccinated. CONCLUSION: Although the relationship between vaccination and VD cannot be established, clinicians should be aware of this rare adverse effect.

Heparin-induced thrombocytopenia in newborns: experience at a pediatric hospital and a literature review.

Background: Heparin-induced thrombocytopenia (HIT) is a rare, difficult-to-diagnose, and potentially serious adverse drug reaction with thrombotic complications. Even though the immune system is still immature during the neonatal period, HIT has been described in newborns with reporting rates ranging from 0% to 2.3%. Therefore, it is important to clarify the risk of HIT in newborns because it can affect the management and monitoring of heparin treatment. Objectives: The objectives of the present study were to review the literature and determine the incidence of HIT after cardiac surgery in newborns in our pediatric hospital. Methods: We searched the literature from 1992 to 2021 for reports of HIT in newborns. Four raters then analyzed all the literature reports on HIT and classified them as "likely," "uncertain," or "unlikely." We also determined the incidence of HIT among newborns having undergone cardiac surgery in our pediatric hospital. Results: Eleven population-based studies and 12 case reports on suspected HIT in 17 newborns were reviewed. One study reported HIT in 14 out of 930 (1.5%) heparin-treated newborns, but the other studies (n = 467 newborns) did not mention HIT at all. None of the cases described in the literature was classified as "likely" by the raters. In our center, none of the 2997 newborns that had undergone cardiac surgery in the previous 16 years was diagnosed with HIT. Conclusion: We conclude that the incidence of HIT in newborns has been overestimated in the literature.

Adverse drugs reactions (ADR) suspected through phone triage and assessed by medically staffed ambulances: A pilot study.

BACKGROUND: Prompt and definitive diagnosis of adverse drug reactions (ADRs) is a challenge for health care providers. There is a global burden of ADRs worldwide associated with a negative impact on the patient's health, in parallel with increasing costs for the community. This study aims to determine the annual incidence of ADRs in the cohort of patients requiring immediate intervention of the French prehospital emergency medical service (PEMS). The definitive diagnosis of ADR was provided by the follow-up of the entire course of hospitalization from PEMS presentation to final discharge in each suspected case. METHODS: A retrospective study examining the incidence of ADR at the Paris PEMS was performed in 2015. RESULTS: From January the 1st to December the 31st, 2015, 485 cases of suspected ADR were selected. Twenty-eight patients could not be identified at the hospital and were considered as lost to follow-up. For the 457 cases with the final diagnosis and outcome available, 359 had a definitive and new diagnosis of ADR, 9 were related to substance of abuse and alcohol, 14 were duplicates and 75 were excluded by drug causality was ruled out. Long-term follow-up was performed for 359 cases. Among them, 22 patients (6.1%) died of an ADR. Twenty-five severe ADRs were notified for children ages 2 to 16 with a cluster of 9 cases (36%) resulting from an accidental outbreak of poisonings with alimemazine in a classroom. No fatality was reported among children suffering from an ADR. CONCLUSION: The collaboration between PEMS and in hospital Pharmacovigilance Centre is feasible from the PEMS report to the long-term follow-up. The definition of a clinical pattern for some drugs is needed to allow the medical team to anticipate the clinical outcome of the involved patient and therefore adapting the patient's support as soon as possible.

Direct Oral Anticoagulants as Successful Treatment of Heparin-Induced Thrombocytopenia: A Parisian Retrospective Case Series.

Background: Heparin-induced thrombocytopenia (HIT) is a prothrombotic life-threatening disorder caused by an adverse reaction to heparin exposure. In this context, it is imperative to stop heparin immediately and to replace it by a non-heparin anticoagulant therapy. Despite their advantages, the use of direct oral anticoagulants (DOACs) is only emerging for HIT treatment, and their use remains rare. Objective: To improve our knowledge on the emerging role of DOACs as treatment of HIT and give an overview of our local practices in this context. Patients/Methods: This is a multi-centric retrospective case series of HIT patients referred to our Parisian pharmacovigilance network and treated with DOACs. Results: We report the cases of seven patients from four healthcare centers, diagnosed with HIT (4T score ≥ 4, positive anti-PF4/heparin immunoassay and positive serotonin-release assay) and treated with DOACs. After a few days on substitutive parenteral treatment (n = 6) or directly at HIT diagnosis (n = 1), these patients were treated with either rivaroxaban (n = 6) or apixaban (n = 1) during acute HIT phase. Mean time to platelet count recovery after heparin discontinuation was 3.3 days (range 3-5). No patient experienced major or clinically relevant non-major bleeding or thrombosis that could be related to DOAC treatment during follow-up. Conclusions: Our cases studies are consistent with recent guidelines credit to the potential and safe use of DOAC during acute HIT in clinically stable patients.

Heparin-induced thrombocytopenia: Construction of a pretest diagnostic score derived from the analysis of a prospective multinational database, with internal validation.

BACKGROUND: Diagnosis of heparin-induced thrombocytopenia (HIT) requires pretest probability assessment and dedicated laboratory assays. OBJECTIVE: To develop a pretest score for HIT. DESIGN: Observational; analysis of prospectively collected data of hospitalized patients suspected with HIT (ClinicalTrials.gov NCT00748839). SETTING: Thirty-one tertiary hospitals in France, Switzerland, and Belgium. PATIENTS: Patients tested for HIT antibodies (2280 evaluable), randomly allocated to derivation and validation cohorts. MEASUREMENTS: Independent adjudicators diagnosed HIT based on the prospectively collected data and serotonin release assay results. RESULTS: Heparin-induced thrombocytopenia was diagnosed in 234 (14.7%) and 99 (14.5%) patients in the two cohorts. Eight features were associated with HIT (in brackets, points assigned for score calculation of the score): unfractionated heparin (1); therapeutic-dose heparin (1); cardiopulmonary bypass (cardiac surgery) (2); major trauma (3); 5- to 21-day interval from anticoagulation initiation to suspicion of HIT (4); ≥40% decrease in platelet count over ≤6 days (3); thrombotic event, arterial (3) or venous (3). The C-statistic was 0.79 (95% CI, 0.76-0.82). In the validation cohort, the area under the receiver operating characteristic curve was 0.77 (95% CI, 0.74-0.80). Three groups of scores were defined; HIT prevalence reached almost 30% in the high-probability group. LIMITATION: The performance of the score may depend on settings and practices. CONCLUSION: The objective, easy-to-collect, clinical features of HIT we evidenced were incorporated into a pretest score, which may guide clinical decisions regarding diagnostic testing and anticoagulation.

Delayed thrombocytopenia following administration of abciximab: Pharmacovigilance survey and literature review.

BACKGROUND: Abciximab (ABX) is used for acute coronary syndrome and unstable angina. Thrombocytopenia is a frequent adverse effect described as occurring in the first 24hours. The aim of this study was to evaluate, in a context of pharmacovigilance survey, the occurrence of delayed thrombocytopenia following ABX infusion in pharmacovigilance database reports and in the literature. METHODS: Individual case safety reports (ICSRs) of delayed thrombocytopenia-between 3 and 30 days - with ABX presented as a single suspect were selected in VigiBase®, the WHO global database of ICSRs. The French cases were then extracted from the French national pharmacovigilance database. In addition, a literature review of published cases was performed using PubMed. RESULTS: Among the 84 ICSRs selected from VigiBase®, 43 were also reported in the FPVD. Mean age was 60.1±12.3 years with a majority of male patients (77.4%). The average time to onset (TTO) was 8.9±5.2 days. Thrombocytopenia regressed in 5.1±2.7 days. Haemorrhagic complications were reported in 15% of ICSRs. In the French cases, the median nadir of platelet count was 28×109/L (range 1-110) with a majority of grade 4 thrombocytopenia (39.5%). The literature review identified 42 cases and provided additional information on administered therapies, which include platelet units, corticosteroids, and IV immunoglobulins. GPIIb/IIIa-ABX complex antibodies were described in 26 published cases. CONCLUSION: Delayed thrombocytopenia, probably due to immune reaction, is a possible life-threatening adverse effect of ABX with a mean TTO of 9 days, supporting the recommendation of a platelet count monitoring during at least two weeks. This recommendation was added to the abcximab SmPC in 2019.

How to interact with medical terminologies? Formative usability evaluations comparing three approaches for supporting the use of MedDRA by pharmacovigilance specialists.

BACKGROUND: Medical terminologies are commonly used in medicine. For instance, to answer a pharmacovigilance question, pharmacovigilance specialists (PVS) search in a pharmacovigilance database for reports in relation to a given drug. To do that, they first need to identify all MedDRA terms that might have been used to code an adverse reaction in the database, but terms may be numerous and difficult to select as they may belong to different parts of the hierarchy. In previous studies, three tools have been developed to help PVS identify and group all relevant MedDRA terms using three different approaches: forms, structured query-builder, and icons. Yet, a poor usability of the tools may increase PVS' workload and reduce their performance. This study aims to evaluate, compare and improve the three tools during two rounds of formative usability evaluation. METHODS: First, a cognitive walkthrough was performed. Based on the design recommendations obtained from this evaluation, designers made modifications to their tools to improve usability. Once this re-engineering phase completed, six PVS took part in a usability test: difficulties, errors and verbalizations during their interaction with the three tools were collected. Their satisfaction was measured through the System Usability Scale. The design recommendations issued from the tests were used to adapt the tools. RESULTS: All tools had usability problems related to the lack of guidance in the graphical user interface (e.g., unintuitive labels). In two tools, the use of the SNOMED CT to find MedDRA terms hampered their use because French PVS were not used to it. For the most obvious and common terms, the icons-based interface would appear to be more useful. For the less frequently used MedDRA terms or those distributed in different parts of the hierarchy, the structured query-builder would be preferable thanks to its great power and flexibility. The form-based tool seems to be a compromise. CONCLUSION: These evaluations made it possible to identify the strengths of each tool but also their weaknesses to address them before further evaluation. Next step is to assess the acceptability of tools and the expressiveness of their results to help identify and group MedDRA terms.

Discrepancy Between Personal Experience and Negative Opinion with Human Papillomavirus Vaccine in Web Forums.

While vaccines are intended to protect people from infectious diseases, public confidence in vaccination has evolved as patients have reservation about vaccination, with a major concern about its safety. Social media may help regulatory authorities to better understand opposition to vaccination and make informed decisions for better promotion of vaccines' benefits towards the public. Our objective was to explore French web forums for potential pharmacovigilance signals associated with human papillomavirus infections (HPV) vaccines. Among 138 posts associated with a signal randomly chosen for manual review, 29% were actually adverse drug reactions to the vaccine described in clinical studies, and only 2 were personal experiences. Only 14% of the reviewed posts described positive opinion about the vaccine whereas 46% were neutral and 40% were negative. While few personal experiences of adverse reactions were actually reported by users, our case study showed a large proportion of negative opinions.

Use of Social Media for Pharmacovigilance Activities: Key Findings and Recommendations from the Vigi4Med Project.

The large-scale use of social media by the population has gained the attention of stakeholders and researchers in various fields. In the domain of pharmacovigilance, this new resource was initially considered as an opportunity to overcome underreporting and monitor the safety of drugs in real time in close connection with patients. Research is still required to overcome technical challenges related to data extraction, annotation, and filtering, and there is not yet a clear consensus concerning the systematic exploration and use of social media in pharmacovigilance. Although the literature has mainly considered signal detection, the potential value of social media to support other pharmacovigilance activities should also be explored. The objective of this paper is to present the main findings and subsequent recommendations from the French research project Vigi4Med, which evaluated the use of social media, mainly web forums, for pharmacovigilance activities. This project included an analysis of the existing literature, which contributed to the recommendations presented herein. The recommendations are categorized into three categories: ethical (related to privacy, confidentiality, and follow-up), qualitative (related to the quality of the information), and quantitative (related to statistical analysis). We argue that the progress in information technology and the societal need to consider patients' experiences should motivate future research on social media surveillance for the reinforcement of classical pharmacovigilance.

5-Fluorouracil-induced hyperammonaemic encephalopathy: A French national survey.

BACKGROUND: 5-Fluorouracil (5-FU)-induced hyperammonaemic encephalopathy is a rare but serious 5-FU adverse drug reaction (ADR). Given the growing number of cancers treated with 5-FU and the paucity of data regarding this ADR, we performed a retrospective national survey to better characterise 5-FU-induced hyperammonaemic encephalopathy. PATIENTS AND METHODS: Since inception of the French pharmacovigilance database, we identified all patients who experienced 5-FU-induced hyperammonaemic encephalopathy. Variables regarding demographics, characteristics, management and outcome of patients were collected. RESULTS: From 1986 to 2018, 30 patients were included. 5-FU-induced hyperammonaemic encephalopathy started 2 [1-4] days after 5-FU infusion onset. Most common neurological disorders were consciousness impairment, seizures and confusion. hyperammonaemia tended to be higher in patients with the lowest Glasgow score and admitted in intensive care unit (ICU) compared to non-ICU patients (250 [133-522] versus 139 [68-220] µmol/L respectively, p = NS). Dihydropyrimidine dehydrogenase deficiency was found in 27% of tested patients (n = 3/11). Encephalopathy-induced mortality was 17%, 57% of patients were admitted in ICU and 70% had a complete neurological recovery within 5 [2-10] days. A 5-FU rechallenge was considered in 14 (67%) patients with neurological recovery and a relapse was observed in 57% of them. No 5-FU-induced hyperammonaemic encephalopathy relapse was observed as long as 5-FU rechallenge was performed with decreased 5-FU dosage. CONCLUSION: We report the largest cohort of 5-FU-induced hyperammonaemic encephalopathy cases so far. This ADR should be suspected and ammonaemia measured in all patients experiencing neurological disorders after 5-FU administration. In patients with complete neurological recovery, a 5-FU rechallenge could be cautiously considered.

Pharmacology and social media: Potentials and biases of web forums for drug mention analysis-case study of France.

The aim of this study is to analyze drug mentions in web forums to evaluate the utility of this data source for drug post-marketing studies. We automatically annotated over 60 million posts extracted from 21 French web forums. Drug mentions detected in this corpus were matched to drug names in a French drug database (Theriaque®). Our analysis showed that a high proportion of the most frequent drug mentions in the selected web forums correspond to drugs that are usually prescribed to young women, such as combined oral contraceptives. The most mentioned drugs in our corpus correlated weakly to the most prescribed drugs in France but seemed to be influenced by events widely reported in traditional media. In this article, we conclude that web forums have high potential for post-marketing drug-related studies, such as pharmacovigilance, and observation of drug utilization. However, the bias related to forum selection and the corresponding population representativeness should always be taken into account.

Secondary Stroke Prevention: A Population-Based Cohort Study on Anticoagulation and Antiplatelet Treatments, and the Risk of Death or Recurrence.

Using claims databases of a public healthcare program (Quebec) for the years 2010-2013, we conducted a cohort study of patients with acute ischemic stroke (AIS) to describe secondary prevention treatments and determine how they stood against practice guidelines. We compared the risk of death or AIS recurrence over 1 year in patients treated with anticoagulants, antiplatelets, and/or other cardiovascular drugs. In the month after discharge, 44.3% of the patients did not receive the recommended treatment and > 20% did not have any treatment. Untreated patients were younger, had less comorbidities, and a more severe AIS. Anticoagulants and antiplatelets were associated with a reduced risk of death or recurrence (hazard ratio (HR) 0.27; 95% confidence interval (CI) 0.20-0.36 and HR 0.25; 95% CI 0.16-0.38, respectively) compared with the untreated group. Effect size was similar for the other treatments. Findings confirm treatment benefits shown in clinical trials and emphasize the importance of AIS secondary prevention.

Acute Digital Ischemia After Arterial Injection of Crushed Zolpidem Tablets: Role of Microcrystalline Cellulose? A Case Report.

Literature is scarce on acute ischemia after intra-arterial injection of crushed tablets and no effective medical treatment against the progression of lesions is reported. The only factor able to modify the outcome is the delay between injection and management by a specialized vascular team. Moreover the risk of necrosis seems higher after benzodiazepine intra-arterial injection than with other drugs. We tried to find out mechanistic explanations. We report on the case of a 31-year-old drug addict woman who self-injected into her left brachial artery crushed tablets of zolpidem. She developed an acute ischemia of the left hand, with necrosis of the intermediate and distal phalanges of fingers II, III, and IV. Angiogram of the left upper arm confirmed the distal arterial occlusions with no run-off after the palmar arch in the necrotic fingers. Once she was admitted into our vascular unit, intravenous vasodilator therapy by iloprost, heparin and local protective care were rapidly introduced. After delineation between living and necrotic tissues, she required distal amputations of the affected fingers. The clinical severity of arterial injections of benzodiazepine tablets is linked to the association of several pathophysiological mechanisms. Rather than related benzodiazepine pharmacologic effects with tissue ischemia, by the inhibition of phosphodiesterase, a vasodilator intermediate, or through the peripheral benzodiazepine-type receptor, the predominant mechanism is more likely in relation with microcrystalline cellulose, one component of zolpidem tablets, known as potential embolic agents. They are insoluble and resistant to degradation in water. These properties are probably prominent in the case we described here. Through this case report we want to drag attention of physicians in charge of a patient with acute ischemia after crushed tablet accidental intra-arterial injection, not only to look at the drug injected but also the other components of the tablet and especially to microcrystalline cellulose.

Dabigatran Level Before Reversal Can Predict Hemostatic Effectiveness of Idarucizumab in a Real-World Setting.

Background: Idarucizumab has been included in guidelines for the management of bleeding or surgical procedure in dabigatran-treated patients without need for biological monitoring. The aim of the study was to assess the prognostic value of dabigatran plasma level before reversal to test the hemostatic efficacy of idarucizumab. The secondary objectives were (i) to analyze plasma dabigatran level according to the risk of rebound and (ii) to evaluate the incidence of post-reversal non-favorable clinical outcomes (including thromboembolism, bleeding, antithrombotic, and death) and antithrombotic resumption. Methods and Results: This was an observational multicentric cohort study, which included all French patients who required idarucizumab for dabigatran reversal. Between May 2016 and April 2019, 87 patients from 21 French centers were enrolled. Patients received idarucizumab for overt bleeding (n = 61), urgent procedures (n = 24), or overdose without bleeding (n = 2). Among patients with major bleeding (n = 57), treatment with idarucizumab was considered effective in 44 (77.2%) of them. Patients who did not achieve effective hemostasis after reversal had a significantly higher mean level of plasma dabigatran at baseline (524.5 ± 386 vs. 252.8 ng/mL ± 235, p = 0.033). Furthermore, patients who did not achieve effective hemostasis after reversal had less favorable outcomes during follow-up (46.2 vs. 81.8%, p = 0.027). ROC curve identified a cutoff of 264 ng/mL for dabigatran level at admission to be predictive of ineffective hemostasis. No plasma dabigatran rebound was observed after reversal in patients with dabigatran plasma level < 264 ng/mL at baseline. Conclusion: This retrospective study shows that dabigatran level before reversal could predict hemostatic effectiveness and dabigatran plasma rebound after idarucizumab injection.

Initial Experiments for Pharmacovigilance Analysis in Social Media Using Summaries of Product Characteristics.

We report initial experiments for analyzing social media through an NLP annotation tool on web posts about medications of current interests (baclofen, levothyroxine and vaccines) and summaries of product characteristics (SPCs). We conducted supervised experiments on a subset of messages annotated by experts according to positive or negative misuse; results ranged from 0.62 to 0.91 of F-score. We also annotated both SPCs and another set of posts to compare MedDRA annotations in each source. A pharmacovigilance expert checked the output and confirmed that entities not found in SCPs might express drug misuse or unknown ADRs.

An Iconic Approach to the Browsing of Medical Terminologies.

Medical terminologies are the basis of interoperability in medicine. They allow connecting the various systems and data and facilitate searches in databases. An example is the MedDRA terminology, used in particular for coding drug adverse events. However, these terminologies are often complex and involve a huge number of terms. Consequently, it is difficult to browse them or find the desired terms. Traditional approaches consist of lexical search, with the problems of synonymy and polysemy, or tree-based navigation, but the user often gets "lost" in the tree. Here, we propose a new approach for browsing medical terminologies: the use of pictograms and icons, for formulating the query in complement to a textual search box, and for displaying the search results. We applied this approach to the MedDRA terminology. We present both the methods and search algorithms and the resulting browsing interface, as well as the qualitative opinions of two pharmacovigilance experts.