A signal for an abuse liability for pregabalin—results from the Swedish spontaneous adverse drug reaction reporting system

A case report of pregabalin misuse leading to drug dependence

Pregabalin misuse and dependence have become emerging concerns in recent years, particularly in regions where traditional drug-related crimes have been curbed, prompting users to seek alternative substances. Although pregabalin is primarily used for treating conditions such as epilepsy, neuropathic pain, and generalized anxiety disorder, its sedative and euphoric effects make it prone to misuse. This case report presents a 20-year-old male who developed pregabalin dependence after using the drug intermittently at escalating doses over a year. He experienced withdrawal symptoms including palpitations, tremors, irritability, insomnia, and auditory hallucinations upon cessation of the drug, which were alleviated by resuming pregabalin use. Upon admission, he was diagnosed with pregabalin dependence, hyperuricemia, and thyroid nodules. The patient underwent a comprehensive treatment plan involving benzodiazepines, antidepressants, and antipsychotics, leading to substantial improvement in mood, anxiety, psychotic symptoms, and withdrawal symptoms. This case highlights the growing issue of pregabalin misuse, the associated withdrawal symptoms, and the importance of early intervention and systematic treatment strategies. It emphasizes the need for stricter prescription controls, patient education on the risks of misuse, and multidisciplinary approaches to the treatment of pregabalin dependence. Further research is necessary to better understand the mechanisms behind pregabalin misuse and to develop improved prevention and treatment protocols.

Perceptions of community pharmacists regarding pregabalin abuse: a survey from Sudan

OBJECTIVES

Pregabalin abuse is increasing in prevalence and is associated with significant harm. This study aimed to assess community pharmacists' perceptions of pregabalin abuse and their recommendations to address this issue.

METHODS

This was a descriptive cross-sectional study conducted in the Omdurman locality, Khartoum in 2022. Community pharmacies were selected randomly and surveyed using a pre-tested and self-administered questionnaire held on a smartphone. Chi-squared and Fisher's exact tests were run using the Statistical Package for Social Sciences version 26.

KEY FINDINGS

A total of 172 community pharmacists completed the questionnaire (77.8% aged 22-30 years, 65.1% females, 79.1% holding bachelor's degrees, and 57.6% having ≤ 5 years of work experience). Most participants (81.4%) perceived that they had observed pregabalin abuse in the last 6 months. Participants indicated that they were aware of the abuse potential of pregabalin (97.7%) and that they routinely dispensed pregabalin only by prescription (92.4%). Most participants reported that people they suspected of abusing pregabalin were mainly men (98.8%), aged 21-30 years (90.7%), and did not regularly visit the pharmacy (72.7%). Actions taken for such customers included stating the product was not available (64.0%) and refusing to dispense (56.4%). The most recommended solutions were raising community awareness about the risks and consequences of pregabalin abuse (35.8%) and maximizing pharmacists' adherence to dispensing regulations (36.5%).

CONCLUSIONS

Most pharmacists believed that they had observed pregabalin abuse and that it was increasing. They managed the situation primarily by reporting the drug was unavailable and refusing to dispense it. Effective community pharmacy-based interventions are strongly needed to tackle the issue of pregabalin abuse.

Characteristics of Non-Therapeutic Pregabalin Users Detected by a Community Pharmacies Network in a Region of Southern Europe

Background: Since 2008, several cases of pregabalin abuse have been reported to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). Despite this evidence, gabapentinoids are increasingly being prescribed. Moreover, pregabalin is being used in a recreational setting for its dissociative effects and euphoria. Objectives: To assess the characteristics of non-therapeutic users of pregabalin and to show behavioral trends associated with requests for the medicine at community pharmacies. Methods: The Medicine Abuse Observatory (MAO), an epidemiological surveillance system, was able to analyze trends about the most diverted drugs and the behavioral patterns of the population from community pharmacies. We have conducted an observational and cross-sectional study from January 2022 to April 2023, to determinate trends in the behavior of patients who have requested pregabalin in the Catalan Sephanet. Results: Behavior with respect to sex was similar in all health problems, although one difference was raised when considering neuropathic pain, in which the females were more involved (72.7%), especially around 2.5 times more than the males (27.3%, p < 0.05). The study showed a potential recreational use related to patients aged <25 years and patients aged 25-35 years (p < 0.05). Neuropathic pain was mainly identified in patients >65 years. In 75% of the cases, there was a preceding prescription. Conclusions: This study underlines the evidence of non-therapeutic use of pregabalin among the Catalan population and the need to take control measures. Actions should be promoted, both at the level of prescription and dispensing, and focusing on education and knowledge about the risks that may appear with the use of pregabalin.

Chronic pregabalin treatment reduced anxiety, and acute pregabalin treatment increased depression-like behaviors in rats

BACKGROUND

Pregabalin is an antiepileptic drug that binds to the alpha-2/delta unit at presynaptic voltage-dependent calcium channels. We aimed to investigate the effect of acute and chronic pregabalin administration on anxiety and depression-like behaviors.

METHODS

Fifty-six male Wistar albino rats were divided into seven groups: control, vehicle, and five different dose groups (5, 10, 30, 60, and 100 mg/kg). Pregabalin was administered for two weeks. Depression-like behaviors were evaluated by Forced swimming test. Anxiety-like behavior (ALB) was evaluated by Open field test (OFT), Elevated Plus Maze (EPM), and light-dark box. Subjects underwent the forced swimming test (FST) after the first dose, while the open field test (OFT), elevated plus maze (EPM), and light-dark box (LDB) were performed after two weeks of treatment. Further sucrose preference test was conducted to evaluate anhedonia until the end of the experiment.

RESULTS

In the forced swimming test, depression-like behaviors increased after acute single-dose administration of 10, 30, 60, 100 mg/kg pregabalin. According to OFT results, chronic 100 mg/kg pregabalin showed anxiolytic effects by decreasing grooming, and freezing behaviors. In addition, 100 mg/kg chronic pregabalin administration significantly increased the time spent in the central region, the number of entries to the center, and the unsupported rearing number without causing any change in locomotor activity. According to EPM results, both chronic 60 and 100 mg/kg pregabalin treatments showed anxiolytic effects by increasing open arm time and head dipping behavior. In addition, 60 and 100 mg/kg chronic pregabalin administration significantly decreased stretch attend posture. All pregabalin administrations between 5 and 100 mg/kg displayed anxiolytic effects in the LDB. Sucrose preference was above 65% for the duration of all experiments and subjects did not show anhedonia.

CONCLUSION

Acute pregabalin treatment triggered depression-like behaviors. Anhedonia, which may be associated with depression, was not observed during chronic treatment. Moreover, chronic treatment with pregabalin revealed potent anxiolytic effects in different behavior patterns and doses for all tests of unconditional anxiety. In particular, 100 mg/kg chronic pregabalin administration decreased anxiety-like behaviors in all experiment setups. Although the anxiolytic effect was demonstrated in chronic treatment, acute treatment of pregabalin induced depression-like behaviors, and thus in clinical practice should be done with caution, especially in patients with anxiety-depression comorbidity.

Patterns of Pregabalin Users from Substance Abuse Treatment Facilities: Results from the French OPPIDUM Program from 2008 to 2022

INTRODUCTION

In recent years, pregabalin has received growing attention due to its abuse liability. The aim of this study was to further characterize patterns of pregabalin users from substance abuse treatment facilities and detect changes in users profile over the study period.

METHODS

The data source was the Observation des Produits Psychotropes Illicites ou Détournés de leur Utilisation Médicamenteuse (OPPIDUM) program, an annual, repeated, cross-sectional, nationwide, multicenter survey that collects consumption data from patients with substance use disorders. First, we described the characteristics of pregabalin users and their consumption patterns. We compared these data between 2008 and 2018 (P1) and 2019 and 2022 (P2). Second, we conducted a multiple correspondence analysis to identify profiles of users.

RESULTS

From 2008 to 2022, 291 pregabalin users (0.37% of all users) from 116 substance abuse treatment facilities were identified. The number of pregabalin users was lower than 15 per year in P1 (n = 89) and between 40 and 60 per year in P2 (n = 202). The number of users who reported pregabalin as the first substance leading to dependence increased significantly in P2 compared with P1 (p < 0.005). When comparing P2 with P1, there was a significant increase in precarity (p < 0.001), users in prison (p = 0.002), withdrawal symptoms (p < 0.001), dependence (p < 0.001), use of higher dose of pregabalin (p = 0.029), and acquisition by deal/street market (p < 0.001). The multiple correspondence analysis allowed for the identification of distinct profiles of pregabalin users: (i) a cluster with mainly users from P1, who presented a simple use of pregabalin, and were older (> 45 years), were involved in opioid agonist treatment (OAT), and obtained pregabalin legally; and (ii) a cluster with mainly users from P2, who presented pregabalin dependence, and were younger (< 26 years), reported pregabalin as the first substance leading to dependence, used doses higher than the market authorization, were in severe precarity, and were in prison.

CONCLUSIONS

These data showed that the profile of pregabalin users has changed in the last years. Pregabalin use disorders also affect users without history of addiction.

Understanding pregabalin misuse and dependence: Insights from a North Indian addiction treatment center

Background

Pregabalin, approved for various medical conditions, has shown increasing misuse potential globally. However, limited research exists on pregabalin dependence in India. This study aimed to investigate the prevalence and characteristics of pregabalin dependence among individuals seeking substance use disorder (SUD) treatment in North India.

Methods

A cross-sectional, analytical study was conducted on patients enrolled between August 2022 and July 2023 at an academic institution-based addiction treatment center. Case records of patients with pregabalin dependence were retrieved and compared with controls with opioid dependence but no history of pregabalin use.

Results

Among 3766 registered patients, 135 had pregabalin dependence (prevalence: 3.58 per 100 registered patients). Pregabalin-dependent patients were male, with a median usage duration of eight months and a median daily dose of 1200 mg. Most had concurrent opioid dependence, primarily heroin, used via the injection route. The odds of pregabalin dependence among those with opioid dependence were significantly higher than those with other substance dependence (OR 1.44, 95% CI 1.13-1.85). Reasons for pregabalin use included opioid craving reduction, sedation, and euphoria. Patients with pregabalin dependence were more likely to have lower socioeconomic status (P < 0.0001) and urban residence (P = 0.032), an earlier age of substance use initiation (P = 0.02) and treatment seeking (P < 0.0001), and a higher co-occurrence of psychiatric disorders (P = 0.007) and less occurrence of alcohol dependence (P = 0.03).

Conclusion

Findings underscore the need for heightened awareness, screening, and intervention efforts targeting pregabalin misuse within SUD treatment. Further research should focus on longitudinal studies to elucidate pregabalin dependence's trajectory.

Content and sentiment analysis of gabapentinoid-related tweets: An infodemiology study

INTRODUCTION

The increasing number of gabapentinoid (pregabalin and gabapentin) harms, including deaths observed across countries is concerning to health-care professionals and policy makers. However, it is unclear if the public shares these concerns. This study aimed to describe posts related to gabapentinoids, conduct a content analysis to identify common themes and describe adverse events or symptoms.

METHODS

Keywords of 'pregabalin' or 'Lyrica' or 'gabapentin' or 'Neurontin' were used to search for related tweets posted by people in the community between 8 March and 7 May 2021. Eligible tweets included a keyword in the post. We extracted de-identified data which included descriptive data of the total number of posts over time; and data on individual tweets including date, number of re-tweets and post content. Data were exported separately for pregabalin- and gabapentin-related tweets. A 20% random sample was used for the thematic analysis.

RESULTS

There were 2931 pregabalin-related tweets and 2736 gabapentin-related tweets. Thematic analysis revealed three themes (sharing positive experiences and benefits of taking gabapentinoids, people voicing their negative experiences, and people seeking opinions and sharing information). Positive experiences of gabapentinoids were related to sharing stories and giving advice. This was contrasted to negative experiences including ineffectiveness, withdrawals, side effects and frustration related to cost and insurance coverage. Brain fog was the most common adverse symptom reported. Gabapentinoid-related deaths were only mentioned in three tweets.

DISCUSSION

The increasing public health concern of gabapentinoid-related deaths was not translated to Twitter discussions.

Review of the demographic factors and toxicology related to deaths due to pregabalin in Northern Ireland

The potential for recreational abuse of the analgesic and antiepileptic drug pregabalin is now well established in the literature. The potential minimum lethal dose in post mortem cases is however less defined. All post mortem examinations in Northern Ireland where the cause of death was found to be due to pregabalin were examined for demographic and toxicological analysis. Deaths are generally seen in young men, especially 30-39-year-olds, many of whom have a history of substance misuse and are often prescribed pregabalin. Until recently, prescription rates have been on the rise regionally. The overall median post mortem peripheral blood concentration of pregabalin found in this study is 10.6 mg/L, however this rises when concurrent drugs and alcohol are considered and in cases where pregabalin is considered responsible for death alone (i.e. outside of multidrug toxicity). Pregabalin peripheral blood concentrations returned in this study suggest previously offered minimum lethal dosages may need to be revised downward.

Trends in the prescription of opioids and gabapentinoids in patients with failed back surgery syndrome in Korea: a population-based study

Background

Failed back surgery syndrome (FBSS) is a chronic condition that is characterized by persistent back pain following one or more spinal surgeries. Pharmacological interventions, such as the use of opioids and gabapentinoids, are frequently used in the treatment of FBSS. However, prolonged and excessive use of these medications can lead to dependence and adverse effects. This study investigates trends in opioid and gabapentinoid prescriptions among patients with FBSS in Korea from 2016 to 2020.

Methods

Data from the Health Insurance and Review Agency were analyzed, and claims listing FBSS were selected for the study. Prescription patterns of opioids and gabapentinoids were classified based on the number of days prescribed per year.

Results

Of the 390,095 patients diagnosed with FBSS, 41.6% of the patients were prescribed gabapentinoids, and 42.0% of them were prescribed opioids, while 10.6% of the patients were classified as long-term gabapentinoid users, 11.4% as long-term opioid users, and 7.4% of the patients were found to have long-term prescriptions for both drugs. The proportion of patients who received both gabapentinoid and opioid prescriptions increased annually. The doses of opioids prescribed have also increased along with the increase in the number of patients receiving opioid prescriptions.

Conclusions

The prescription rates of opioids and gabapentinoids among patients with FBSS in Korea continue to increase steadily, posing potential risks of addiction and adverse effects. Further research is needed to better understand the actual status of addiction in patients with FBSS.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for treatment of anxiety, obsessive-compulsive and posttraumatic stress disorders - Version 3. Part I: Anxiety disorders

AIM

This is the third version of the guideline of the World Federation of Societies of Biological Psychiatry (WFSBP) Task Force for the Pharmacological Treatment of Anxiety, Obsessive-Compulsive and Posttraumatic Stress Disorders (published in 2002, revised in 2008).

METHOD

A consensus panel of 33 international experts representing 22 countries developed recommendations based on efficacy and acceptability of available treatments. In total, 1007 RCTs for the treatment of these disorders in adults, adolescents, and children with medications, psychotherapy and other non-pharmacological interventions were evaluated, applying the same rigorous methods that are standard for the assessment of medications.

RESULT

This paper, Part I, contains recommendations for the treatment of panic disorder/agoraphobia (PDA), generalised anxiety disorder (GAD), social anxiety disorder (SAD), specific phobias, mixed anxiety disorders in children and adolescents, separation anxiety and selective mutism. Selective serotonin reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRIs) are first-line medications. Cognitive behavioural therapy (CBT) is the first-line psychotherapy for anxiety disorders. The expert panel also made recommendations for patients not responding to standard treatments and recommendations against interventions with insufficient evidence.

CONCLUSION

It is the goal of this initiative to provide treatment guidance for these disorders that has validity throughout the world.

Patterns of pregabalin prescribing in four German federal states: analysis of routine data to investigate potential misuse of pregabalin

OBJECTIVES

The objectives of this study were to investigate the utilisation patterns of pregabalin, to identify users potentially misusing pregabalin and to compare this group of patients to patients prescribed recommended doses of pregabalin concerning their personal characteristics and the coordination among their prescribers. Unintended coprescription of drugs with addictive potential might occur when care is insufficiently coordinated.

DESIGN

Secondary data analysis of linked data from three regional sickness funds in Germany (AOK) for the years 2014-2016.

SETTING

Ambulatory and hospital care sector in four German federal states.

METHODS

On the basis of routine data, patients who received at least three prescriptions of pregabalin were identified and classified into patients prescribed pregabalin as recommended and those dispensed with a higher than recommended dose (>600 mg/day). Social network analysis was applied to identify prescription networks and to analyse cooperation among the prescribers. With descriptive statistics and univariate statistical tests, typical characteristics of the group of patients potentially misusing pregabalin were compared with the others.

RESULTS

Among the 53 049 patients prescribed pregabalin, about 2% (877) were classified as potentially misusing pregabalin. The majority of this group was male and aged between 30 and 60 years. Of the patients misusing pregabalin, 365 (42%) had a diagnosed history of substance use disorders and 359 (41%) had been prescribed another drug with addictive potential (opioids) before. The prescribers of those patients potentially misusing pregabalin were more loosely connected within networks compared with prescribers of patients prescribed pregabalin as recommended.

CONCLUSION

This study found that patients could exceed recommended doses of pregabalin by getting prescriptions from multiple physicians. Specific patients were at increased risk of potentially misusing pregabalin, and these patients sought to obtain their prescriptions from physicians who were as loosely connected as possible. Coordination and sharing a relevant number of patients seem to be levers to avoid these problems of unintended coprescribing.

Management of Pregabalin Use Disorder: A Case Series

Pregabalin is indicated for the treatment of partial epilepsy, generalized anxiety disorder, and neuropathic pain. The first reports on pregabalin use disorder have been published in Europe in 2010 and notified to the French Addictovigilance Network (FAN) in 2011. The management of pregabalin use disorder is challenging due to the risks associated with the abrupt withdrawal and lack of guidelines. In this retrospective observational study, the management of pregabalin use disorder was analyzed in eight cases reported to the addictovigilance center of Montpellier, France, between 2019 and 2020. Most of these patients had a history of illicit psychoactive substance use. During the withdrawal period, patients experienced mainly psychiatric problems, nervous system symptoms, general disorders, and gastrointestinal symptoms. Multiple strategies were proposed for these patients to manage pregabalin withdrawal, such as hospitalization and pregabalin gradual dose reduction with or without adjuvant medications. Two patients relapsed and the others were lost to follow up. Although other reports of pregabalin use disorder have been published, recommendations or guidelines for its management are not yet available. The current case series and the previous reports suggest that the use of adjunctive therapy may be useful to limit the risk of convulsions and anxiety.

Chinese-Named Entity Recognition From Adverse Drug Event Records: Radical Embedding-Combined Dynamic Embedding-Based BERT in a Bidirectional Long Short-term Conditional Random Field (Bi-LSTM-CRF) Model

Background

With the increasing variety of drugs, the incidence of adverse drug events (ADEs) is increasing year by year. Massive numbers of ADEs are recorded in electronic medical records and adverse drug reaction (ADR) reports, which are important sources of potential ADR information. Meanwhile, it is essential to make latent ADR information automatically available for better postmarketing drug safety reevaluation and pharmacovigilance.

Objective

This study describes how to identify ADR-related information from Chinese ADE reports.

Methods

Our study established an efficient automated tool, named BBC-Radical. BBC-Radical is a model that consists of 3 components: Bidirectional Encoder Representations from Transformers (BERT), bidirectional long short-term memory (bi-LSTM), and conditional random field (CRF). The model identifies ADR-related information from Chinese ADR reports. Token features and radical features of Chinese characters were used to represent the common meaning of a group of words. BERT and Bi-LSTM-CRF were novel models that combined these features to conduct named entity recognition (NER) tasks in the free-text section of 24,890 ADR reports from the Jiangsu Province Adverse Drug Reaction Monitoring Center from 2010 to 2016. Moreover, the man-machine comparison experiment on the ADE records from Drum Tower Hospital was designed to compare the NER performance between the BBC-Radical model and a manual method.

Results

The NER model achieved relatively high performance, with a precision of 96.4%, recall of 96.0%, and F1 score of 96.2%. This indicates that the performance of the BBC-Radical model (precision 87.2%, recall 85.7%, and F1 score 86.4%) is much better than that of the manual method (precision 86.1%, recall 73.8%, and F1 score 79.5%) in the recognition task of each kind of entity.

Conclusions

The proposed model was competitive in extracting ADR-related information from ADE reports, and the results suggest that the application of our method to extract ADR-related information is of great significance in improving the quality of ADR reports and postmarketing drug safety evaluation.

Extracorporeal Treatment for Gabapentin and Pregabalin Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup

Toxicity from gabapentin and pregabalin overdose is commonly encountered. Treatment is supportive, and the use of extracorporeal treatments (ECTRs) is controversial. The EXTRIP workgroup conducted systematic reviews of the literature and summarized findings following published methods. Thirty-three articles (30 patient reports and 3 pharmacokinetic studies) met the inclusion criteria. High gabapentinoid extracorporeal clearance (>150mL/min) and short elimination half-life (<5 hours) were reported with hemodialysis. The workgroup assessed gabapentin and pregabalin as "dialyzable" for patients with decreased kidney function (quality of the evidence grade as A and B, respectively). Limited clinical data were available (24 patients with gabapentin toxicity and 7 with pregabalin toxicity received ECTR). Severe toxicity, mortality, and sequelae were rare in cases receiving ECTR and in historical controls receiving standard care alone. No clear clinical benefit from ECTR could be identified although major knowledge gaps were acknowledged, as well as costs and harms of ECTR. The EXTRIP workgroup suggests against performing ECTR in addition to standard care rather than standard care alone (weak recommendation, very low quality of evidence) for gabapentinoid poisoning in patients with normal kidney function. If decreased kidney function and coma requiring mechanical ventilation are present, the workgroup suggests performing ECTR in addition to standard care (weak recommendation, very low quality of evidence).

Community Pharmacists' Perceptions towards the Misuse and Abuse of Pregabalin: A Cross-Sectional Study from Aseer Region, Saudi Arabia

Pregabalin is a first-line therapy for neuropathic pain and for chronic pain. It has abuse potential. This study was conducted to assess community pharmacists’ perceptions towards pregabalin abuse and misuse in the Aseer region, Saudi Arabia, and identify predictors and associated factors. A cross-sectional survey using a structured questionnaire following a self-administrative study was conducted across community pharmacies in the Aseer region (Abha, Khamis Mushait, Mahayel, Sarat Abeeda, Ahad-Rufaida, and Bishah). A total of 206 respondents from community pharmacists participated in the study. Over the last six months, 136 respondents (66.0%) suspected pregabalin abuse in community pharmacies; male dominance in pregabalin abusers was also recorded (n = 165, 80.1%). Additionally, 40 (19.4%) respondents stated that a prescription was not issued for pregabalin demands. Over half (61.7%) of community pharmacists recorded an increased change in pregabalin abuse compared to the previous year. This is the first study to explore pharmacists’ perceptions in the community of the Aseer region towards customers’ misuse and abuse of pregabalin. Further monitoring and regulations on the prescribing and procurement of pregabalin are needed to avoid abuse.

Development and validation of a rapid liquid chromatography/tandem mass spectrometry method to quantitate gabapentin and buprenorphine in human serum

RATIONALE

Gabapentin has shown initial promise as an opioid-sparing medication in pain patients as well as a treatment for opioid withdrawal and liquid chriomatography/tandem mass spectrometry (LC/MS/MS) is often used for clinical monitoring. Despite reports of validated tandem mass spectrometric methods for the determination of gabapentin and buprenorphine, mechanisms for the collision-induced fragmentation have not been adequetely described.

METHODS

A rapid analytical method has been developed to determine gabapentinoid, gabapentin, and the partial opioid agonist, buprenorphine, in 20 μL of human serum using LC/MS/MS with a chromatographic run time of 2 min. A simplified sample cleanup procedure using methanol precipitation of serum proteins/lipids followed by evaporation and reconstitution in mobile phase was demonstrated. Gabapentin and buprenorphine were detected following positive ion electrospray ionization using multiple-reaction monitoring. The internal standard approach was used for quantitation with labeled gabapentin-D10 and buprenorphine-D4 serving as internal standards. Using organic reaction principals and stable isotope labels, collision-induced fragmentation mechanisms for both gabapentin and buprenorphine are proposed. The method was validated according to the FDA Guidance for Industry - Bioanalytical Method Validation.

RESULTS

Accuracy was demonstrated by error values ≤15% for buprenorphine and ≤6% for gabapentin. The inter-day precision was ≤4.88% and 15.59% for gabapentin and buprenorphine and the intra-day precision was ≤5.20% and 11.65% for gabapentin and buprenorphine. The lower limit of quantitation corresponded to 10 ng/mL for gabapentin and 1 ng/mL for buprenorphine in serum. Recoveries were 104 ± 2.55% and 85 ± 2.03% for gabapentin and buprenorphine, respectively.

CONCLUSIONS

Concentrations of gabapentin and buprenorphine were determined for five authentic human serum samples to further validate the utility of the method and applicable to therapeutic drug monitoring beyond its use as a drug screening assay. Furthermore, new mechanisms for the collision-induced dissociation of gabapentin and buprenorphine have been proposed.

The gabapentinoid drugs and their abuse potential

The gabapentinoid drugs, gabapentin and pregabalin, are first-line treatments for neuropathic pain. The epidemics of chronic pain and opioid misuse have given rise to the widespread use of non-opioid drugs such as the gabapentinoids for treatment. Unfortunately, the widespread use of gabapentinoid drugs has resulted in reports of misuse and abuse. Here we summarize the clinical reports of gabapentinoid abuse in different patient populations to help inform clinical practice of chronic pain management.

Beyond the 'purple drank': Study of promethazine abuse according to the European Medicines Agency adverse drug reaction reports

BACKGROUND

Promethazine is a medicinal product, available on its own or in combination with other ingredients including dextromethorphan, paracetamol and/or expectorants. Anecdotal reports have however indicated that promethazine may have a misuse potential, especially in adolescents.

OBJECTIVE

We here aimed at studying how this phenomenon has been reported to the European Monitoring Agency Adverse Drug Reactions database.

METHODS

After a formal request to the European Monitoring Agency, the promethazine-specific dataset has been studied, performing a descriptive analysis of misuse/abuse/dependence-related adverse drug reaction reports. The study was approved by the University of Hertfordshire (LMS/PGR/UH/03234).

RESULTS

The analysis of promethazine data showed increasing levels of misuse/abuse/ dependence issues over time (2003-2019). Out of a total number of 1543 cases of adverse drug reactions, the abuse/misuse/dependence-related cases reported were 557, with 'drug abuse' (300/557: 53.8%) and 'intentional product misuse' (117/557: 21.0%). being the most represented adverse drug reactions. A high number of fatalities were described (310/557: 55.6%), mostly recorded as 'drug toxicity/drug abuse' cases, with opiates/opioids having been the most commonly reported concomitant drugs used.

CONCLUSION

Anecdotal promethazine misuse/abuse reports have been confirmed by European Monitoring Agency data. Promethazine misuse/abuse appears to be an alarming issue, being associated with drug-related fatalities. Thus, healthcare professionals should be warned about a possible misuse of promethazine and be vigilant, as in some countries medicinal products containing promethazine can be purchased over the counter. Since promethazine is often available in association with opioids, its abuse may be considered a public health issue, with huge implications for clinical practice.

Pregabalin and gabapentin in non-opioid poisoning deaths

Post-mortem findings of gabapentinoids have often been connected to drug abuse and especially opioid use. We aimed to investigate whether gabapentinoids have been implicated in the cause of death without the presence of opioids. In a three-year study period from 2016 to 2018, a total of 907 Finnish post-mortem cases positive for pregabalin or gabapentin were found. In nearly half of the pregabalin cases and in a third of the gabapentin cases, the blood concentration was above the typical therapeutic range of the drug. Of the cases in which pregabalin was detected, in 35% the drug was implicated in a fatal poisoning with or without other drugs or alcohol. For gabapentin, the percentage was 22%. In most of the fatal gabapentinoid poisonings, opioids or other central nervous system depressants were additionally detected in relevant concentrations. There were eight non-opioid gabapentinoid poisonings, in which no relevant other drugs were detected. Many of these cases were unintentional poisonings with a relatively high gabapentinoid concentration in the blood. In all but one, the manner of death was accidental, or the intent was undetermined. This study confirmed the previous findings that gabapentinoids are mostly implicated in fatal poisoning together with opioids. Half of the non-opioid cases were related to drug abuse but in the other half the death was presumably caused by overuse of a prescribed drug or suicide. While the use of gabapentinoids is a well-known problem among people who use drugs, it is important to note other groups of users who may be at risk of overdose by gabapentinoids.

Prevalence of and Factors Associated with Gabapentinoid Use and Misuse Among Texas Medicaid Recipients

BACKGROUND AND OBJECTIVES

Gabapentin and pregabalin have been considered relatively safe opioid-sparing adjuncts for pain management. However, rising prescribing trends, presence of gabapentinoids in opioid-related overdoses, and the growing body of evidence regarding gabapentinoid misuse and abuse, have caused gabapentinoids to emerge as a drug class of public health concern. This study aimed to assess the prevalence of, and factors associated with gabapentinoid use and misuse.

METHODS

This retrospective study of Texas Medicaid data from 1/1/2012 to 30/8/2016 included patients aged 18-63 years at index date, with ≥ 1 gabapentinoid prescription, and continuously enrolled 6 months pre-index and 12 months post-index. Gabapentinoid misuse was defined as ≥ 3 claims exceeding daily doses of 3600 mg for gabapentin and 600 mg for pregabalin. Age, gender, concurrent opioid use, neuropathic pain diagnoses and gabapentinoid type were independent variables. Descriptive and inferential statistics were used.

RESULTS

Of included subjects (N = 39,000), 0.2% (N = 81) met study criteria for gabapentinoid misuse. Overall, the majority (76.4%) of gabapentinoid users were aged 41-63 years with a mean ± SD age of 48.2 ± 10.7 years. Those patients meeting the study criteria for gabapentinoid misuse were significantly younger (45.1 ± 11.0 vs 48.2 ± 10.7, p = 0.0084). Majority of the study sample was female (68.1%). However, a significantly higher proportion of males met the study criteria for gabapentinoid misuse compared to females (0.3% vs 0.2%, p = 0.0079). Approximately one-half (51.9%) of the study sample had neuropathic pain, and gabapentinoid misuse was significantly higher in neuropathic pain patients compared to those without neuropathic pain (0.3% vs 0.1%, p = 0.0078). Over three-quarters (77.4%) of patients were using gabapentin; however, gabapentinoid misuse was significantly higher among pregabalin users (0.4% vs 0.2%, p = 0.0003). Approximately 20% (17.3%) of gabapentinoid users had ≥ 90 days of concurrent opioid use. However, there was no significant difference in gabapentinoid misuse among patients with concurrent opioid use compared to patients without (0.3% vs 0.2%, p = 0.1440). Factors significantly associated with misuse included: male sex (odds ratio [OR] 0.486; 95% confidence interval [CI] 0.313-0.756; p = 0.0013); neuropathic pain (OR 2.065; 95% CI 1.289-3.308; p = 0.0026); and pregabalin versus gabapentin use (OR 2.337, 95% CI 1.492-3.661; p = 0.0002). Concurrent opioid use was not significantly associated with gabapentinoid misuse (OR 1.542, 95% CI 0.920-2.586; p = 0.1006).

CONCLUSION

Prevalence of gabapentinoid misuse was low (0.2%) among Texas Medicaid recipients. Younger age, male gender, neuropathic pain diagnosis and pregabalin use were significantly associated with higher levels of gabapentinoid misuse.

Pregabalin for neuropathic pain in primary care settings: recommendations for dosing and titration

Pregabalin is one of the first-line treatments approved for the management of neuropathic pain (NeP). While many patients benefit from treatment with pregabalin, they are often treated with suboptimal doses, possibly due to unfamiliarity around prescribing the drug and/or side effects that can occur with up-titration. This narrative review discusses key aspects of initiating, titrating, and managing patients prescribed pregabalin therapy, and addresses concerns around driving and the potential for abuse, as well as when to seek specialist opinion. To ensure that patients derive maximum therapeutic benefit from the drug, we suggest a 'low and slow' dosing approach to limit common side effects and optimize tolerability alongside patients' expectations. When requiring titration to higher doses, we recommend initiating 'asymmetric dosing,' with the larger dose in the evening. Fully engaging patients in order for them to understand the expected timeline for efficacy and side effects (including their resolution), can also help determine the optimal titration tempo for each individual patient. The 'low and slow' approach also recognizes that patients with NeP are heterogeneous in terms of their optimal therapeutic dose of pregabalin. Hence, it is recommended that general practitioners closely monitor patients and up-titrate according to pain relief and side effects to limit suboptimal dosing or premature discontinuation.

Trends in new prescription of gabapentinoids and of coprescription with opioids in the 4 nations of the UK, 1993-2017

We explored potential differences in time trends of gabapentinoid prescription and of opioid coprescription between 1993 and 2017 in the 4 UK nations using the Clinical Practice Research Datalink, a UK primary care database. There were distinct trends in annual rates of new gabapentin and pregabalin prescriptions in Northern Ireland. The rate of new gabapentin prescriptions rapidly increased after 2010 and exceeded that of the other nations by 2017 (rate of 836 [95% confidence interval: 787-887] per 100 000 person-years). Additionally, the rate of new pregabalin prescriptions was higher during the entire study period, reaching a peak of 1139 (95% confidence interval: 1088-1193) per 100 000 person-years in 2010, 5-fold higher than the other nations. Findings in Northern Ireland may be partly attributable to the high burden of anxiety disorders, an indication for pregabalin. Further exploration of reasons for discrepancies in gabapentinoid prescribing between UK nations is warranted.

Forensic application and evaluation of a commercially available pregabalin immunoassay test in serum on an Olympus AU480

Misuse of pregabalin and its forensic relevance is steadily increasing. The aim of this study was to evaluate the usability of the commercially available ARKTM Pregabalin II Assay (ARK Diagnostics) for serum analysis of forensic samples. Overall, 156 samples were tested by both the immunoassay and a validated liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method. Sensitivity was 100%, and specificity was 98.7% (n = 79 positive cases confirmed by LC-MS/MS in a range of 380-37,000 ng/mL). A good correlation (R²  = 0.73) could also be shown between quantitative immunoassay and LC-MS/MS results. In conclusion, the assay shows excellent reliability for screening of forensic serum samples.

[Pregabalin abuse and dependence in various European countries: Association with substitution policies]

INTRODUCTION

Pregabalin was first approved in 2004 for the treatment of peripheral neuropathic pain and focal epileptic seizures, with or without secondary generalization. Prescription frequency has increased significantly since approval. In the early days, little attention was paid to the problem of misuse and dependence on pregabalin; in recent years, there has been a significant increase in the number of publications focusing on this problem. This review deals with these risk factors and risk groups of pregabalin abuse and dependence in different European countries and their drug policies.

RESULTS

Pregabalin abuse and dependence has increased significantly since its introduction to the market. It was shown that solo abuse of pregabalin is rare. In most cases, pregabalin was combined with other substances, which is also a predictor of pregabalin abuse. There were different reasons for the non-prescription use of pregabalin; it was used to increase the psychotropic effect, on the one hand, and to alleviate withdrawal symptoms, on the other hand. Furthermore, in Sweden, pregabalin was found in 28% of fatal intoxications among drug addicts. Young people were particularly affected. Abuse of pregabalin was detected in countries with restrictive substitution programmes, while in countries with liberal drug policies, no abuse was detected. However, the data situation in Switzerland with a liberal substitution programme is based on only one study, which is why pregabalin use in liberal substitution programmes cannot be conclusively clarified.

CONCLUSIONS

There seems to be a connection between a country's drug policy and the illegal use of pregabalin among persons in a substitution programme in that country. There are also risk factors and risk groups for pregabalin dependence and abuse.

Gabapentinoid Abuse in France: Evidence on Health Consequences and New Points of Vigilance

Introduction: Gabapentinoid drugs (gabapentin and pregabalin) are widely used worldwide for epileptic and pain disorders. First signals of gabapentinoid abuse occurred in the last decade. This study aims to describe clinical characteristics of gabapentinoid use related disorders and health consequences in France. Materials and Methods: We designed a multisource investigation reviewing data reported to the French Addictovigilance Network (FAN) with pregabalin and gabapentin from 2010 to 2019. Information was obtained through the analysis of Spontaneous Reports (SRs) notified by health professionals and the pharmacoepidemiological surveys OSIAP (suspicious prescriptions forms indicators of potential abuse), OPPIDUM (observation of illicit drugs and misuse of psychotropic medications), DRAMES (death related to prescription drugs and other substances), and DTA (toxic deaths due to analgesics). Results: Over 2010-2019 period, were collected: (i) 265 SRs (258 pregabalin; 7 gabapentin); (ii) 816 forged prescription forms (805 pregabalin, 10 gabapentin, 1 involving both drugs); (iii) 145 cases of gabapentinoid use in people who use drugs (121 pregabalin; 24 gabapentin) and (iv) 31 cases of gabapentinoid-related deaths (25 pregabalin; 6 gabapentin). Risk factors of gabapentinoid abuse were opioid use disorders or psychiatric history, but cases of primary abuse in subjects without any substance abuse history were observed. Adverse outcomes concern almost exclusively pregabalin, with coma, dyspnea, convulsion, and conduction disorders. Treatment demands increased from 10.6% in 2018 to 23.1% in 2019, with pregabalin cited as the first substance leading to addictological care in the 2019 OPPIDUM survey. Gabapentinoid-related deaths increased over time. Pregabalin has become the first drug mentioned in forged prescriptions in 2019 (23.8% of OSIAP), while it ranked at the 15th position in 2017 (2.6%). Discussion: This study shows the importance of addictovigilance monitoring for gabapentinoids. Addictovigilance data helped to make visible the gabapentinoid-abuse related health harms (hospitalization for serious neurologic, psychiatric or cardiac effects, requests for addictological support and deaths) and to confirm the intrinsic abuse potential of pregabalin. These data highlight new points of vigilance considering observed primary abuse. At this point in France, the risk of abuse and related complications is very apparent with pregabalin. Still, it is identical to that observed elsewhere with gabapentin.

Profile of Substance Misuse among Adolescent and Young Adult Gabapentinoid Users: A Register-Based Follow-up Study of Former Adolescent Psychiatric Inpatients

Our study examined characteristics of adolescent and young adult study participants using gabapentinoids (gabapentin, pregabalin), with previous history of adolescent psychiatric inpatient hospitalization. Particular focus was on temporal association of age, at first prescription for gabapentinoids, to age at tobacco smoking initiation, regular alcohol use, diagnosis of substance dependence and prescriptions for benzodiazepines and opioids. Methods: The initial study population contained 508 adolescents (300 females, 208 males) admitted to psychiatric inpatient care in Oulu University hospital between the ages 13-17 years. Register-based follow-up information on prescriptions for gabapentinoids, benzodiazepines and opioids, as well as ICD-10 diagnosis for hospital-treated substance dependence, was obtained from the Finnish national health care registers. Results: The users of gabapentinoids accounted for 9.1% of the initial study population. Of adolescence-related characteristics, suicidal ideation, suicide attempts and non-suicidal self-injury was emphasized in females using gabapentinoids. The majority of participants using gabapentinoids had benzodiazepines (80.4%) and opioids (71.7%) as comorbid drugs. Initiation of tobacco smoking and alcohol use and first prescriptions for of benzodiazepines and opioids, and a diagnosis of substance dependence commonly predated first prescriptions for gabapentinoids. Conclusions: In clinical practice, the decision to prescribe gabapentinoids to adolescents or young adults must be made with caution, particularly for those with substance use problems and/or without a clinically approved indication.

Non-medical Use of Prescription Gabapentinoids (Gabapentin and Pregabalin) in Five European Countries

Background: Non-medical use (NMU) of prescription GABA analogs (pregabalin and gabapentin) has been reported especially in opiate dependent persons. However, by now the prevalence of NMU of gabapentinoids in the general population has not been sufficiently evaluated. The aim of this research paper is to determine the prevalence of prescription GABA analog NMU and associated demographics in five European countries with special detail of Spain. Methods: The RADARS Survey of Non-Medical Use of Prescription Drugs Program (NMURx) is a harmonized series of contemporaneous cross-sectional surveys of adults conducted in multiple countries. NMURx collects data from the general population in each participating country about NMU of prescription drugs, illicit drugs, and associated demographics. NMU was defined as "using a medication without a doctor's prescription or for any reason other than what was recommended by their doctor." Responses from Spain (4Q2017, n=10,062) were analyzed in detail. Comparative data were available from France, Germany, Italy, and UK. Responses were collected using non-probability quota sampling and post-stratification population weighting was applied to reflect the national distributions of adults, based on age, gender, and census region. Rates of NMU and associated demographics were reported as rate of past 90-day NMU per 100,000 adult population with 95% confidence intervals. Results: Germany (1,197 per 100,000 adult population [95% CI: 1,004.3-1,379.1]) and United Kingdom (1,067 per 100,000 adult population [95% CI: 851.3-1,283.2]) presented the highest prevalence of gabapentinoids NMU. In Spain the prevalence of past 90 days GABA analog NMU was: 344.4, 95% (CI 204.8-484.0), with male predominance. Those who non-medically use GABA analogs had a higher prevalence of lifetime chronic pain, lifetime illicit drug use, and previous substance abuse treatment. In Spain, 20% of respondents who ever have used gabapentinoids, reported a lifetime NMU; the prevalence was higher for pregabalin 624 (6.2%) than for gabapentin 444 (4.4%). The main reasons for use were to self-treat pain and other medical conditions. Conclusions: The risk of NMU of gabapentinoids should not be neglected. Subjects with a history of chronic pain and lifetime substance use disorders had an increased risk of NMU of gabapentinoids.

Current Evidence on Abuse and Misuse of Gabapentinoids

This review summarizes current evidence on the abuse and misuse of the gabapentinoids pregabalin and gabapentin. Pharmacovigilance studies, register-based studies, surveys, clinical toxicology studies, and forensic toxicology studies were identified and scrutinized with the goal to define the problem, identify risk factors, and discuss possible methods to reduce the potential for abuse and misuse. Studies found that gabapentinoids are abused and misused and that individuals with a history of psychiatric disorders or substance use disorder seem to be at high risk. Moreover, some evidence supports the notion that patients with opioid use disorders may be at an increased risk of abusing gabapentinoids. Available evidence also suggests that abuse and misuse are more frequent in users of pregabalin compared with users of gabapentin. Health professionals and prescribers should be aware of the risk for misuse of pregabalin and gabapentin, which eventually could lead to abuse, substance dependence, and intoxications. Prescribing to patients belonging to risk populations such as those with psychiatric disorders or substance use disorder should be avoided if possible and, if prescribed, signs of misuse and abuse should be monitored.

Abuse and Misuse of Pregabalin and Gabapentin: A Systematic Review Update

BACKGROUND

A 2017 systematic review (SR) identified 59 studies examining gabapentinoid (pregabalin and gabapentin) misuse/abuse. Evidence of gabapentinoid misuse/abuse has since grown substantially.

OBJECTIVE

Update previous SR and describe new insights regarding gabapentinoid abuse.

METHODS

A SR of PubMed was conducted to identify studies published from 7/29/2016-8/31/2020. Four searches were performed using the following terms: "gabapentin [MeSH] OR pregabalin [MeSH] OR gabapentinoid" AND one of the following substance misuse/abuse-related terms: "substance-related disorders [MeSH]", "overdose", "abuse", or "misuse". Clinicaltrials.gov and the Cochrane Library database were searched to identify ongoing studies or similar SRs. Reference lists of included studies were reviewed to identify additional literature. All studies with novel data related to pregabalin and/or gabapentin abuse, misuse, or overdose conducted during the study period were included. Articles not written in English, review articles, and animal studies were excluded.

RESULTS

Fifty-five studies were included (29 [52.7%] from North America, 17 [30.9%] Europe, 6 [10.9%] Asia, and 3 [5.5%] Australia). Forty-six observational studies and 10 case reports/series were included (one manuscript included both). Twenty (36.4%) studied gabapentin only, 18 (32.7%) pregabalin only, and 17 (30.9%) both pregabalin/gabapentin. These studies corroborate findings from the previous SR that gabapentinoids are increasingly abused or misused to self-medicate, that gabapentinoids can produce desirable effects alone but are often used concomitantly with other drugs, and that opioid use disorder is the greatest risk factor for gabapentinoid abuse. While the original SR identified the largest studies having been published in Europe, this review identified several more generalisable US studies that have subsequently been conducted. The most concerning finding was increased evidence of associated patient harm, including increased hospital utilisation and opioid-related overdose mortality risk.

CONCLUSION

Evidence suggests that gabapentinoid misuse/abuse represents a growing trend that is causing significant patient harm. Prescribers should exercise appropriate caution with use in high-risk populations and monitor for signs of misuse or abuse.

Gabapentinoids for treatment of alcohol use disorder: A systematic review and meta-analysis

OBJECTIVE

Gabapentin (GBP) and pregabalin (PGB) have been used to treat alcohol use disorder (AUD) and alcohol withdrawal, but with inconsistent results. In this meta-analysis, we explored the effects of GBP/PGB treatment on AUD and their effects on withdrawal, craving, depression, and sleep disturbance in AUD patients.

METHODS

We carried out a systematic review and meta-analysis of randomized controlled trials comparing the effects of GBP/PGB on AUD with those of a placebo or control treatment. Electronic databases were searched for relevant articles published before September 2019. The primary outcome was defined as the efficacy measure on achieving abstinence or reducing alcohol consumption in a hierarchical order. We included 16 studies in our meta-analysis.

RESULTS

Overall, GBP had no significant benefit comparing to placebo or control treatment (Hedges' g = 0.0725, p = 0.6743). For specific alcohol-related outcome, GBP had significant effect on percentage of heavy drink (Hedges' g = 0.5478, p = 0.0441) and alcohol withdrawal symptoms (Hedges' g = 0.2475, p = 0.0425). GBP/PGB did not have significant beneficial effect on craving, depressive symptoms, or sleep disturbance. Instability was shown in sensitivity analyses of some above results.

CONCLUSIONS

GBP may be helpful to reduce AUD patients' heavy drinking behavior and withdrawal, but more studies are needed for drawing conclusions.

Ten-year trend of opioid and nonopioid analgesic use in the French adult population

AIMS

Analgesics are the most widely used medicines worldwide. In parallel, opioid abuse has increased and is of major concern. The accessibility of pharmacologically powerful medicines and the addictovigilance signals in France about the risk of opiates addiction call for an overview of analgesic use. The objective of this study was to investigate the use of analgesics reimbursed in France over a 10-year period through its prevalence.

METHODS

A cross-sectional study repeated yearly was conducted by using data from the French reimbursement database from 2006 to 2015. Analgesics were classified according to their pharmacological potency: prevalence of use for each category and sociodemographic characteristics of patients treated were analysed.

RESULTS

The annual prevalence of analgesic use was high and increased during the study period (59.8%, 253 976 users in 2015). In 2015, prevalence was always higher in women and increased with age, except for those older than 84 years. Peripheral analgesics were the most used (55.3%, 234 739 users). The prevalence of weak analgesic use decreased (21.3%, 90 257 users), mainly due to the definitive withdrawal of dextropropoxyphene in France in 2011, which was not offset by an increase in the consumption of other weak analgesics. For strong analgesics (1.2%, 5129 users), morphine was the most widely used, with a dramatic increase in oxycodone use, especially in the elderly.

CONCLUSION

The prevalence of analgesic use is high: approximately 31 million adults had at least 1 analgesic reimbursed in 2015. The most widely used analgesics were peripheral analgesics, far ahead of opioid analgesics.

Gabapentin-induced drug-seeking-like behavior: a potential role for the dopaminergic system

Drugs of abuse represent a growing public health crisis. Accumulating evidence indicates that gabapentin (GBP), a prescription drug, is prone to misuse, abuse, withdrawal, and dependence. Commonly, drugs of abuse modulate the dopaminergic system to induce addiction. In this study, we used the conditioned place preference (CPP) model to investigate the involvement of the dopamine 1 (D1) receptor on the reward and reinforcement behavior of GBP. Under a CPP paradigm, male BALB/c mice were intraperitoneally injected either saline or 100, 200, or 300 mg/kg of GBP and confined to the injection-paired chamber for 30 min. In the pre-conditioning phase, mice were conditioned for 3 days, and baseline data were collected. In the conditioning phase, mice were given once-daily alternating injections of either GBP or saline for 8 days and subsequently assessed in a post-conditioning test. Injections of 300 mg/kg of GBP significantly increased the time spent in the drug-paired chamber compared to the saline-paired chamber. However, lower doses of GBP (100 and 200 mg/kg) showed no effect. Pre-treatment with SKF-83566, a D1 receptor antagonist, attenuated GBP-induced CPP. Thus, for the first time, we show that GBP can induce CPP through a dopaminergic-dependent mechanism.

[Pregabalin and risk of addiction: A new care issue?]

PURPOSE

Pregabalin (PRG) is a gamma-aminobutyric acid (GABA) analogue used for treatment of epilepsy, neuropathic pain, generalised anxiety disorder and currently being studied for other indications. Supported by the results of case studies and a limited number of studies, there is an ongoing debate about the addictive potential of PRG. However, evidence is scarce and no definitive assessment on the potential for abuse and dependence to PRG is available. The objective of our study was to identify the number of cases of abuse or dependence to PRG published and to study potential risk factors of addiction to PRG.

METHODS

We have identified on PubMed and ScienceDirect published case studies of PRG abuse or dependence and analysed these cases on the basis of several clinical parameters.

RESULTS

A total of 118 cases of PRG abuse or dependence were identified, including 21 isolated cases (mean age 33 years, 67 % men). The mean daily dose of PRG was 2,9 g. Current or past polydrug abuse was present in the majority of cases. Psychiatric diagnoses, other than substance-related disorders, were reported in as many patients, and almost all patients experienced withdrawal symptoms when PRG was discontinued.

CONCLUSION

Current literature suggests an important and growing concern for the abuse of PRG. Male sex, psychiatric and/or addiction history, including opioid addiction, may be potential risk factors for the development of addictive behaviours associated with PRG.

Pregabalin-induced sexual disinhibition

INTRODUCTION

Sexual side effects have rarely been reported secondary to treatment with Pregabalin, a structural analogue of the inhibitory neurotransmitter gamma amino butyric acid (GABA).

METHOD

We present the case of AB, a 27-year-old single man with a diagnosis of recurrent depressive disorder who was prescribed pregabalin to alleviate the significant anxiety symptoms he was experiencing.

RESULTS

A significant amelioration in anxiety symptoms was attained; however, he developed the adverse effects of acute sexual disinhibition and increased libido. These adverse effects were temporally related to treatment with pregabalin and reduced with dose reduction of this agent.

CONCLUSIONS

To date, limited published data are available relating such a reaction to pregabalin. A greater clinical recognition of this association between pregabalin and sexual disinhibition, would allow clinicians to intervene at an earlier stage of this adverse effect and potentially as in this case, management may only require dose reduction rather than treatment discontinuation.

Pregabalin induced visual hallucinations - a rare adverse reaction

Background

Pregabalin is an anticonvulsive, analgesic and anxiolytic medication. The typical side effects include dizziness, somnolence and weight gain. Few studies or case reports have demonstrated psychiatric side effects resulting from its use.

Case presentation

We present a patient who suffered visual hallucinations and agitation associated with an increase in pregabalin dose, resolving completely after pregabalin discontinuation.

Conclusions

Acute visual hallucinations should be considered in the clinical spectrum of very rare side effects of pregabalin use, especially at higher doses. Tapered discontinuation of the medication can improve and resolve symptoms.

An Insight into Gabapentin and Pregabalin in Scottish Prisoners

The aim of this study was to evaluate the prevalence and abuse potential of antiepileptic drugs (AEDs) among prison populations in Scotland, UK. Participants consisted of all admitted and released prisoners over a 1 month period who consented to provide samples. Urine samples were collected and analyzed by liquid chromatography coupled with triple quadrupole tandem mass spectrometry using a method validated for the simultaneous quantification of 21 AEDs in urine. A total of 904 samples were collected. The samples were also screened for drugs of abuse by using point-of-care testing kits. A total of 18% of the samples were positive for AEDs. Gabapentin (GBP) was identified in 118 samples (13%) and pregabalin (PRG) in 32 samples (3.5%). Interestingly, 12 samples contained both drugs (1.3%). The concentrations ranged from 0.5 to 1,100 mg/L (median, 15 mg/L) for GBP and from 0.5 to 440 mg/L (median, 7.3 mg/L) for PRG. Four samples were found to have concentrations &gt;400 mg/L, two samples for GBP and two samples for PRG. These concentrations are at least 20 times above the median concentrations. Other AEDs detected were levetiracetam (four samples), vigabatrin (four samples), lamotrigine (three samples), valproic acid (three samples), carbamazepine (two samples) and topiramate (one sample). Illicit or non-prescribed drugs were detected in 81% of urine samples of which 80% were from admitted prisoners and 20% from released prisoners. Benzodiazepines, opiates and cannabis were the most frequently detected drugs. Other drugs found in positive AED samples were methadone (26%), cocaine (18%), buprenorphine (17%), amphetamines (4%), methamphetamines (4%) and barbiturates (4%). This study shows a high prevalence of AEDs within the Scottish prison system, primarily due to GBP and PRG; however, due to the anonymity of the sample collection, it is unknown if these are prescribed or illicit drug ingestions.

A repeated cross-sectional study of factors associated with pregabalin-positive poisoning deaths in Ireland

BACKGROUND

The increasing use of pregabalin and the presence of pregabalin in poisoning deaths, particularly with opioids, highlight it as a potential drug of abuse. In this study we examined factors associated with pregabalin-positive poisoning deaths (PPPD) between 2013 and 2016 in Ireland.

METHODS

Data were extracted from the National Drug-Related Deaths Index (NDRDI). Analysis included univariate and multivariate logistic regression to estimate unadjusted and adjusted odds ratios (OR) and 95 % confidence intervals (CI) for factors associated with PPPD (primary outcome) by logistic regression models for the total sample and stratified by gender.

RESULTS

Pregabalin was present on 240 (16 %) toxicology reports of 1489 poisoning deaths; significantly rising from 15 (4.5 %) in 2013 to 94 (26 %) in 2016. Women (AOR 2.69, 95 % CI: 1.95-3.70), opioid misuse (AOR 1.74, 95 % CI: 1.17-2.59), in receipt of treatment for problem drug use (AOR 1.95, 95 % CI: 1.33-2.86) and year of death (2016 vs 2013) (AOR 7.95, 95 % CI: 4.58-13.79) were associated with increased odds of PPPD. Alcohol dependence was associated with reduced odds of PPPD (AOR 0.59, 95 % CI: 0.41-0.85). For men, opioid misuse, in receipt of treatment for problem drug use, and year of death were associated with increased odds of PPPD, while alcohol dependence was associated with reduced odds of PPPD. For women, in receipt of treatment for problem drug use and year of death were associated with increased odds of PPPD.

CONCLUSIONS

Enhanced training to prescribers and treatment providers on the potential risks associated with pregabalin, particularly among people who use drugs, is required.

Gabapentin drug misuse signals: A pharmacovigilance assessment using the FDA adverse event reporting system

BACKGROUND

Although there have been increasing reports of intentional gabapentin misuse, epidemiological evidence for the phenomenon is limited. The purpose of this study was to determine whether there are pharmacovigilance abuse signals for gabapentin.

METHODS

Using FDA Adverse Events Reporting System reports from January 1, 2005 to December 31, 2015, we calculated pharmacovigilance signal measures (i.e., reporting odds ratio, proportional reporting ratio, information component, and empirical Bayes geometric mean) for abuse-related adverse event (AR-AE)-gabapentin pairs. Loglinear modeling assessed the frequency of concurrent reporting of abuse-related and abuse-specific AEs (AS-AEs) associated with gabapentin. Findings were compared to a positive (pregabalin) and negative (duloxetine) control.

RESULTS

From 2005-2015 there were 5,951,229 unique AE reports submitted to the FDA including 99,977 for gabapentin, 73,977 for duloxetine, and 97,813 for pregabalin. Significant drug-AR-AE pair signals involving gabapentin included: drug abuser, multiple drug overdose, and substance-induced psychotic disorder. Significant drug AR-AE signals involving gabapentin and pregabalin, but not duloxetine, were: ataxia, dependence, drug abuse, increased drug tolerance, and overdose. Compared to duloxetine, gabapentin had significantly greater odds of a co-report for an AS-AE with drug withdrawal syndrome (OR: 6.55), auditory hallucinations (OR: 4.57), delusions (OR: 2.36), euphoric mood (OR: 5.45), ataxia (OR: 2.85), drug abuser (OR: 3.01), aggression (OR: 1.98), psychotic disorder (OR: 1.96), and feeling abnormal (OR: 1.31).

CONCLUSIONS

We identified abuse-related signals for gabapentin and highlighted several CNS effects that may be associated with its abuse. Gabapentin prescribers should be aware of the drug's abuse liability and effects that may accompany its use.

Intranasal Pregabalin Administration: A Review of the Literature and the Worldwide Spontaneous Reporting System of Adverse Drug Reactions

Background: It is repeatedly reported that pregabalin (PRG) and gabapentin feature a potential for abuse/misuse, predominantly in patients with former or active substance use disorder. The most common route of use is oral, though reports of sublingual, intravenous, rectal, and smoking administration also exist. A narrative review was performed to provide an overview of current knowledge about nasal PRG use. Methods: A narrative review of the currently available literature of nasal PRG use was performed by searching the MEDLINE, EMBASE, and Web of Science databases. The abstracts and articles identified were reviewed and examined for relevance. Secondly, a request regarding reports of cases of nasal PRG administration was performed in the worldwide spontaneous reporting system of adverse drug reactions of the European Medicines Agency (EMA, EudraVigilance database). Results: The literature search resulted in two reported cases of nasal PRG use. In the analysis of the EMA-database, 13 reported cases of nasal PRG use (11 male (two not specified), mean age of users = 34.2 years (four not specified)) were found. In two cases fatalities occurred related to PRG nasal use. Conclusions: Even if only little evidence can be found in current literature, the potential for misuse/abuse of PRG via nasal route might be of particular importance in the near future in PRG users who misuse it. Physicians should be aware of these alternative routes of administration.

Named entity recognition from Chinese adverse drug event reports with lexical feature based BiLSTM-CRF and tri-training

BACKGROUND

The Adverse Drug Event Reports (ADERs) from the spontaneous reporting system are important data sources for studying Adverse Drug Reactions (ADRs) as well as post-marketing pharmacovigilance. Apart from the conventional ADR information contained in the structured section of ADERs, more detailed information such as pre- and post- ADR symptoms, multi-drug usages and ADR-relief treatments are described in the free-text section, which can be mined through Natural Language Processing (NLP) tools.

OBJECTIVE

The goal of this study was to extract ADR-related entities from free-text section of Chinese ADERs, which can act as supplements for the information contained in structured section, so as to further assist in ADR evaluation.

METHODS

Three models of Conditional Random Field (CRF), Bidirectional Long Short-Term Memory-CRF (BiLSTM-CRF) and Lexical Feature based BiLSTM-CRF (LF-BiLSTM-CRF) were constructed to conduct Named Entity Recognition (NER) tasks in free-text section of Chinese ADERs. A semi-supervised learning method of tri-training was applied on the basis of the three established models to give un-annotated raw data with reliable tags.

RESULTS

Among the three basic models, the LF-BiLSTM-CRF achieved the highest average F1 score of 94.35%. After the process of tri-training, almost half of the un-annotated cases were tagged with labels, and the performances of all the three models improved after iterative training.

CONCLUSIONS

The LF-BiLSTM-CRF model that we constructed could achieve a comparatively high F1 score, and the fusion of CRF, while BiLSTM-CRF and LF-BiLSTM-CRF in tri-training might further strengthen the reliability of predicted tags. The results suggested the usefulness of our methods in developing the specialized NER tools for identifying ADR-related information from Chinese ADERs.

Lack of correlation between the activity of the mesolimbic dopaminergic system and the rewarding properties of pregabalin in mouse

RATIONALE

Pregabalin is a psychoactive drug indicated in the treatment of epilepsy, neuropathic pain, and generalized anxiety disorders. Pregabalin acts on different neurotransmission systems by inactivating the alpha2-delta subunit of voltage-gated calcium channels. In light of this pharmacological property, the hypothesis has been raised that pregabalin may regulate the mesolimbic dopamine pathway and thereby display a potential for misuse or abuse as recently observed in humans. Although some preclinical data support this possibility, the rewarding properties of gabapentinoid are still a matter for debate.

OBJECTIVE

The aim of this work was to evaluate the rewarding properties of pregabalin and to determine its putative mechanism of action in healthy mice.

RESULTS

Pregabalin alone (60 mg/kg; s.c.) produced a rewarding effect in the conditioned place preference (CPP) test albeit to a lower extent than cocaine (30 mg/kg; s.c.). Interestingly, when assessing locomotor activity in the CPP, the PGB60 group, similarly to the cocaine group, showed an increased locomotor activity. In vivo single unit extracellular recording showed that pregabalin had mixed effects on dopamine (DA) neuronal activity in the ventral tegmental area since it decreased the activity of 50% of neurons and increased 28.5% of them. In contrast, cocaine decreased 75% of VTA DA neuronal activity whereas none of the neurons were activated. Intracerebal microdialysis was then conducted in awake freely mice to determine to what extent such electrophysiological parameters influence the extracellular DA concentrations ([DA]ext) in the nucleus accumbens. Although pregabalin failed to modify this parameter, cocaine produced a robust increase (800%) in [DA]ext.

CONCLUSIONS

Collectively, these electrophysiological and neurochemical experiments suggest that the rewarding properties of pregabalin result from a different mode of action than that observed with cocaine. Further experiments are warranted to determine whether such undesirable effects can be potentiated under pathological conditions such as neuropathic pain, mood disorders, or addiction and to identify the key neurotransmitter system involved.

Patterns of gabapentin and pregabalin use and misuse: Results of a population-based cohort study in France

AIMS

The aim of this study was to assess the use and factors associated with the misuse of gabapentin and pregabalin in the general French population, through a cohort study in the EGB (General Sample of Beneficiaries), a national representative sample of the French general population.

METHODS

New users of gabapentin and pregabalin were identified from June 2006 to December 2014, and new users of duloxetine served as control group. Misuse was defined as a use of higher daily doses than recommended. Cox proportional hazard regression models were performed to identify associated factors of misuse.

RESULTS

Misuse was more frequent in the 8692 new users of pregabalin (12.8%) than in the 1963 gabapentin (6.6%) or the 3214 duloxetine new users (9.7%) (P < 0.001). Factors associated with misuse were pregabalin (hazard ratio [HR] 1.48; 95% confidence interval [CI] [1.29-1.69]), age (HR_{[18-45] versus > 70 years} 1.98 [1.70-2.31] and HR_{[58-70] versus > 70 years} 1.25 [1.06-1.47]), multiple prescribers (HR_{2 or 3 versus 1 prescriber} 1.29 [1.15-1.45]; HR_{4 or more versus 1 prescriber} 1.54 [1.30-1.83]), cancer (1.28 [1.11-1.47]), multiple sclerosis (1.53 [1.07-2.18]), neuropathy (1.85 [1.19-2.89]), depression (1.26 [1.07-1.49]) and methadone (2.61 [1.16-5.84]). After this first episode of drug misuse, 11.6% of gabapentin and 10.7% of pregabalin misusers developed a primary addiction.

CONCLUSION

In a cohort of new users, misuse is more likely to occur in new users of pregabalin, with different associated factors of misuse compared to gabapentin and duloxetine. Health professionals and prescribers must be aware of this misuse potential, which could lead to abuse and dependence.