Pregabalin abuse and dependence in Germany: results from a database query

Monitoring misuse and abuse of psychoactive substances in France: Insights from substance abuse treatment facilities through the OPPIDUM program

The OPPIDUM program was first created in 1990. It is an annual, repeated, cross-sectional, nationwide, multicenter program. Data are provided directly from users of psychoactive substances (PAS) seen in substance abuse treatment facilities. The OPPIDUM program includes sociodemographic data, data on the first PAS used and leading to dependence, data on PAS use in the week prior the interview and the modality of use. The OPPIDUM program contributes to characterize patterns of SPA use and detect changes in modalities of use or/and in users profiles. It relies on the acceptability and adhesion of the growing number of participating substance abuse treatment facilities for more than 30years, giving informative data at the national and regional level. In 2023, the OPPIDUM program gathers data from about 117,822 participants describing 239,959 patterns of PAS use (with more than 5000 participants each year). In this article, we reviewed the success of the oldest program of the French Addictovigilance Network (history, development, evolution and contribution) for the assessment and surveillance of substance abuse.

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.

Methamphetamine as the most common concomitant substance used with pregabalin misuse

BACKGROUND AND AIM

Non-medical use of Pregabalin (PGB) is a growing concern in many countries because of the serious consequences associated with their abuse. Judicial cases within the probation system, multiple drug users, and patients in treatment programs administered PGB at higher doses than suggested, commonly without prescription. For this reason, it is important to analyze PGB by adding it to the routine analysis scale in determining whether PGB is used for medical purposes or abuse. In this study, PGB analyzed (single or multiple substance use, concomitant substances) in urine samples of forensic and clinical cases by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition to the sociodemographic and clinical characteristics of pregabalin-positive cases, the results were evaluated separately from a clinical and forensic perspective.

METHODS

All urine samples which was admitted to Addiction Toxicology Laboratory from 'drug abuse probation system' (forensic cases, n = 640) and from various departments of our hospital (clinical cases, n = 371) between December 2022 and April 2023. Screening analysis were carried out by immunoassay in total 1011 cases. LC-MS/MS method simultaneously analyzed amphetamine, benzoilecgonine, cocaine, codeine, metamphetamine, morphine, 3,4-metilenedioksi-N-metilamfetamin (MDMA), 11-nor-9-karboksi-Δ9-tetrahidrokannabinol and pregabalin in urine samples. PGB was added to the our routine substance screening analysis scale in December 2022 to detect pregabalin use.

RESULTS

PGB was detected in 12.3% of probabition cases and 13.2% of clinical cases. The mean age of PGB positive cases was 26.55 ± 7,52 years old, predominantly males (%85,9). Single PGB was detected in 53.2% of forensic cases (n = 42), and 38.7% of clinical cases (n = 19). The most common substance detected concomitantly with PGB was amphetamine type stimulants (ATSs:amphetamine, methamphetamine, ecstasy/MDMA etc.) (22.8% of forensic cases and 46.9% of clinical cases), followed by concomitant cannabis use (24.1% of forensic cases and 26.5% of clinical cases). Concomitant opioid use was rare (1.3% of forensic cases and 4.1% of clinical cases). Detection of PGB was significantly different across months on which the samples were collected (x2 = 82.8, df=4, p < 0.001).

CONCLUSION

Inconsistently with previous studies suggesting opioids as the most prevalant substances concominant with PGB, our results showed that stimulants (especially ATSs) were the most prevelant substances concominant with PGB, followed by cannabis. High proportion of PGB detection in probabition cases, frequently as a single substance abuse takes attention. These results suggest that PGB, may be used to avoid legal consequences. It is important for laboratories to be aware that they need to make changes as addition of newly abused substances in their analysis panels, when necessary, as differences between regions and cultures affect substance use patterns.

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.

Misuse of gabapentinoids (pregabalin and gabapentin) in patients with neuropathic pain related to spinal cord injury

OBJECTIVE

To investigate the misuse of gabapentinoids (pregabalin and gabapentin) in patients with neuropathic pain related to spinal cord injury.

STUDY DESIGN

Cross-sectional study.

SETTING

Outpatient clinic in a physical therapy and rehabilitation hospital.

PARTICIPANTS

127 patients, aged 18-70 years, who had neuropathic pain related to spinal cord injury (SCI) and disease duration of at least 12 months.

OUTCOME MEASURES

Gabapentinoid use disorder of the patients was determined based on the DSM-5 diagnostic criteria for substance-related disorders. Patients were divided into 2 groups as those with drug misuse and those without drug misuse. Demographic and clinical information of the patients were compared between the groups. Factors associated with drug misuse were analyzed.

RESULTS

The misuse rate was 81.9% in patients using pregabalin and 69.69% in patients using gabapentin. Duration of disease and the Leeds assessment of neuropathic symptoms and signs (LANSS) score were statistically significantly higher in the drug misuse group. A statistically significant difference was found between the groups in terms of marital status, education and income level, and smoking and alcohol use. A statistically significant relationship was observed between drug misuse and duration of disease and LANSS score.

CONCLUSION

Misuse of gabapentinoids is prevalent in patients with neuropathic pain related to spinal cord injury. The duration of disease and the severity of NP are associated with misuse. Clinicians should exercise caution when prescribing gabapentinoids to patients with SCI.

Effect of amoxicillin/clavulanic acid in attenuating pregabalin-induced condition place preference

Substance abuse is a worldwide problem with serious repercussions for patients and the communities where they live. Pregabalin (Lyrica), is a medication commonly used to treat neuropathic pain. Like other analgesic medications there has been concern about pregabalin abuse and misuse. Although it was initially suggested that pregabalin, like other gabapentinoids, has limited abuse liability, questions still remain concerning this inquiry. Changes in glutamate system homeostasis are a hallmark of adaptations underlying drug dependence, including down-regulation of the glutamate transporter 1 (GLT-1; SLC1A2) and the cystine/glutamate antiporter (xCT; SLC7A11). In this study, it was found that pregabalin (90 mg/kg) produces a conditioned place preference (CPP), indicative of reinforcing effects that suggest a potential for abuse liability. Moreover, like other drugs of abuse, pregabalin also produced alterations in glutamate homeostasis, reducing the mRNA expression of Slc1a2 and Slc7a11 in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC). Amoxicillin clavulanic acid, a β-lactam antibiotic, blocked the reinforcing effects of pregabalin and normalized glutamate homeostasis. These results suggest that pregabalin has abuse potential that should be examined more critically, and that, moreover, the mechanisms underlying these effects are similar to those of other drugs of abuse, such as heroin and cocaine. Additionally, these results support previous findings showing normalization of glutamate homeostasis by β-lactam drugs that provides a novel potential therapeutic approach for the treatment of drug abuse and dependence.

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.

Comparative Study of the Neurotoxic Effects of Pregabalin Versus Tramadol in Rats

In Egypt, both pregabalin and tramadol misuse increased in the last decade. Although many studies have confirmed the neurotoxic effects of tramadol, those of pregabalin are understudied. The aim of the study is to evaluate the neurotoxic effects of pregabalin compared with tramadol. Thirty male albino rats were included in this experimental study, and they were randomly allocated into three equal groups: group I (normal saline), group II (tramadol misuse), and group III (pregabalin misuse). All rats received the commenced drugs for 1 month. Open field tests were performed on the day of scarification, and after that, cortical samples were taken for immunohistochemical analysis and quantification of dopamine receptors' gene expression. The drug misuse groups showed a significant decrease in weight gain at the end of the study. Open field testing showed the upper hand of controls regarding all of the tested parameters. Tramadol has a more negative impact on the locomotor parameters compared with pregabalin. Both drugs induced relatively low dopamine-1 receptor (D1Rs) expression to dopamine-2 receptors (D2Rs), mimicking the schizophrenia model. Both tramadol and pregabalin were associated with neurotoxic effects in male albino rats. These effects were less noticed with pregabalin. It is suggested that long-term abuse may end in psychosis.

Pregabalin abuse and dependence during insomnia and protocol for short-term withdrawal management with diazepam: examples from case reports

Introduction:

Pregabalin (PGN) is an anxiolytic, analgesic, antiepileptic, and hypnotic medication. There are concerns about its abuse in the community for managing chronic insomnia and other risks when assumed in overdose or combination with other abuse substances. PGN is classified as a controlled medication. While its discontinuation is accompanied by rebound insomnia and other neurological symptoms, cross-tapering PGN with short-term diazepam (DZ) during inpatient admissions has shown promising results in dealing with PGN withdrawal symptoms accompanied by rebound insomnia.

Material and Methods:

We report three cases that began abusing their prescribed PGN. During hospital admission, our teams used a protocol for cross-tapering PGN with DZ to reduce withdrawal symptoms. Other sedative medications are suspended while alcohol is not allowed if patients are on leave from the hospital. Standardized scales for assessment were clinical global impression scale-severity (CGI-S), generalized anxiety disorder scale (GAD-7), and insomnia severity index (ISI).

Results:

The cross-tapering PGN with DZ showed similar clinical outcomes with reduced withdrawal symptoms and rebound insomnia during two weeks of cross-tapering. Eventually, DZ, too, is stopped in the hospital to avoid another dependence syndrome.

Conclusion:

As emerging in the current study, PGN has strong addictive effects in people who have insomnia and is mostly abused for its hypnotic or sleep-inducing properties when other medications have failed. As applied in the current study, DZ can manage PGN withdrawal symptoms with rebound insomnia while cross-tapering. DZ is then discontinued.

Managing the misuse potential and risk of psychological harm from gabapentinoids in primary care in New Zealand

Gabapentinoid prescribing is increasing in New Zealand. International evidence suggests that this prescribing trend is followed by increasing harms, including misuse, dependence, overdose, and psychological harms including suicidal thoughts or behaviours. However, there is limited guidance for prescribers on how to manage these potential harms. Here, we summarise the current international literature and identify three main risk factors that can be used for screening purposes when considering prescribing a gabapentinoid, to identify patients that may be at greater risk of harm. Based on current knowledge of harms, we provide guidance to prescribers on monitoring patients taking gabapentinoids. Finally, we summarise the evidence regarding tapering, and highlight key knowledge gaps including other interventions, referral, and data from primary care populations.

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.

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).

Gabapentinoids: The rise of a new misuse epidemics?

Gabapentinoids and opioids have in common that they are used in medicine in the treatment of pain, and by addicts in recreational use. In recent years, in the context of the "opioid epidemics", gabapentinoids, which had a reputation for low risk of abuse, have been increasingly prescribed. This was accompanied by increasingly frequent abuses, the patients most at risk being those suffering from opiate addiction. However, gabapentinoids increase the risks associated with opioids or other sedatives, due to a synergy of central depressant effects. This leads to reconsider the framework of their prescription and the management of chronic pain.

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.

Potential Benefits of N-Acetylcysteine in Preventing Pregabalin-Induced Seeking-Like Behavior

Substance-use disorder is globally prevalent and responsible for numerous social and medical problems. Pregabalin (Lyrica), typically used to treat diabetic neuropathy, has recently emerged as a drug of abuse. Drug abuse is associated with several neuronal changes, including the downregulation of glutamate transporters such as glutamate transporter 1 and cystine/glutamate antiporter. We investigated the effects of N-acetylcysteine, a glutamate transporter 1 and xCT upregulator, on pregabalin addiction using a conditioned place preference paradigm. Pregabalin (60 mg/kg) was found to induce conditioned place preference when compared to a vehicle. A 100 mg/kg dose of N-acetylcysteine was found to block pregabalin-seeking behaviors. These results support previous findings showing that glutamate transporters play an important role in pregabalin-induced seeking behaviors. N-acetylcysteine may represent a beneficial agent in preventing the abuse potential of pregabalin.

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 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.

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.

Molecular and hormonal changes caused by long-term use of high dose pregabalin on testicular tissue: the role of p38 MAPK, oxidative stress and apoptosis

In 1990, pregabalin was introduced as a novel antiepileptic drug that acts by binding selectively to the alpha-2-delta subunits of voltage-gated calcium channels resulting in increasing neuronal GABA levels and inhibiting the release of exciting neurotransmitters. The aim of our study is to assess the hazardous effects of prolonged high-dose pregabalin (like that abused by addicts) on testes and to clarify the potential causative mechanisms. The current study was conducted on 70 adult male Wistar albino rats which were divided into 7 groups. In our study we evaluated the effect of pregabalin, at concentrations 150 and 300 mg/kg/day for 90 days, on hormones; FSH, LH, testosterone and prolactin secretion. Our study also evaluated the expression of apoptosis-related genes BAX and BCL2 in testicular tissue in addition to the western blotted analysis of p38 Mitogen activated protein kinases (p38 MAPK). The levels of reduced glutathione, malondialdehyde and superoxide dismutase were also measured. Pregabalin decreased testosterone level while FSH, LH and prolactin showed a significant increase. It also produced genotoxicity through reversal of the BAX/BCL2 ratio; increased p38 MAPK level and induction of oxidative stress markers. The concomitant administration of vitamin E significantly reduced all the previously mentioned biochemical and hormonal adverse effects caused by pregabalin. Pregabalin can adversely affect male fertility particularly in addicts and patients who are being treated with it for long periods as those suffering from neuropathies and seizures. Antioxidants like vitamin E could have a role in amelioration.

Non-medical use of benzodiazepines and GABA analogues in Europe

AIMS

We investigated the prevalence of non-medical use (NMU) of benzodiazepines and GABA analogues in Europe.

METHODS

Data were collected using the online Non-Medical Use of Prescription Drugs (NMURx) survey from France, Germany, Italy, Spain and the UK.

RESULTS

The study included 55 223 eligible surveys which, after post-stratification weights were applied, represented approximately 260 million European adults. Lifetime NMU of benzodiazepines was highest in Spain (6.5%, 95% CI: 6.0-7.0) and lowest in Germany (1.7%, 1.5-2.0). Lifetime NMU of GABA analogues was highest in Germany (5.4%, 5.0-5.7) and lowest in France (2.2%, 1.9-2.5) and the UK (2.2%, 1.9-2.6) While no notable difference was observed for France or the UK, there was a higher prevalence of last 12-month NMU of benzodiazepines compared to GABA analogues in Italy (2.4 times higher) and Spain (3.0 times higher) and a higher prevalence of NMU of GABA analogues compared to benzodiazepines in Germany (2.6 times higher).

CONCLUSION

This study shows that there is variation in NMU of benzodiazepines and GABA analogues among countries. Of particular interest is the high incidence of GABA analogue NMU in Germany and benzodiazepine NMU in Spain. Further research to identify factors and motivations responsible for the higher prevalence observed are essential to inform public health policies in those countries.

[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.

Dispensations of benzodiazepines, z-hypnotics, and gabapentinoids to patients receiving opioid agonist therapy; a prospective cohort study in Norway from 2013 to 2017

Background

Dispensations of benzodiazepines, z-hypnotics, and gabapentinoids to patients on opioid agonist therapy (OAT) are common and have pros and cons. The objectives of the current study are to define the dispensation rates of these potentially addictive drugs, and whether the number and the mean daily doses of dispensed OAT opioids and discontinuing OAT, are associated with being dispensed benzodiazepines, z-hypnotics and gabapentinoids among patients on OAT in Norway in the period 2013 to 2017.

Methods

Information about all dispensed opioids, benzodiazepines, z-hypnotics and gabapentinoids were recorded from the Norwegian Prescription Database (NorPD). A total of 10,371 OAT patients were included in the study period. The dispensation rates were defined as the number of patients who were dispensed at least one of the potentially addictive drugs divided among the number of patients who have dispensed an OAT opioid per calendar year. Mean daily doses were calculated, and for benzodiazepines and z-hypnotics, stated in diazepam equivalents. The association between dispensed potentially addictive drugs, and the number and the type of dispensed OAT opioids were calculated by using logistic regression models.

Results

Half of the OAT patients received at least one dispensation of a benzodiazepine or z-hypnotic, and 11% were dispensed at least a gabapentinoid in 2017. For dispensed benzodiazepines or z-hypnotics, the mean daily dose was reduced from 21 mg (95% confidence interval (CI): 20–23) diazepam equivalents in 2013 to 17 mg (95% CI: 16–17) in 2017. The mean daily dose of pregabalin increased from 365 mg (95% CI: 309–421) in 2013 to 386 mg (95% CI: 349–423) in 2017. Being dispensed a gabapentinoid (adjusted odds ratio (aOR) = 2.5, 95% CI: 2.1–3.0) or a non-OAT opioid (aOR = 3.0, 95% CI: 2.6–3.5) was associated with being dispensed a benzodiazepine or z-hypnotic. Discontinuing OAT did not affect the number of dispensations and the doses of potentially addictive drugs.

Conclusion

The dispensation rates of potentially addictive drugs are high in the OAT population. Treatment indications, as well as requirements for prescription authority, need to be debated and made explicit. Randomized controlled trials evaluating the benefits and risks of such co-prescription are required.

Pregabalin and Its Involvement in Coronial Cases

Pregabalin is an anticonvulsant and analgesic designed to treat neuropathic pain and partial seizure disorders and has been available in Australia as a prescription medication since 2005. Studies have found high rates of polydrug use associated with pregabalin and it is reportedly used recreationally for its euphoric and relaxing effects as well as to self-manage opioid withdrawal symptoms. A robust analytical method for the analysis of pregabalin using protein precipitation and LC/MS/MS was developed, validated and employed in routine case work. In recent years a substantial increase in pregabalin detections in coronial case submissions had been noted. This study examines the case characteristics and outcomes of 332 coronial cases submitted to the laboratory and analyzed for pregabalin between 2015 and 2017. Pregabalin was identified in approximately 5% of all coronial cases submitted during this time. A high rate of concurrent drug use with pregabalin was evident with the predominant classes being opioids, benzodiazepines and anti-depressants. Post-mortem blood pregabalin concentrations ranged from <0.05 to 140 mg/kg (median 5.5 mg/kg); however, limited interpretation of levels could be achieved as the drug was rarely identified in the absence of other drugs. Cause of death (COD) was found to be drug related in 58% of all cases, with mixed drug toxicity specifically mentioned as related to COD in 40% of cases.

Diabetic Polyneuropathy - Advances in Diagnosis and Intervention Strategies

Over half of people with diabetes mellitus develop diabetic polyneuropathy (DPN), which is a major cause of reduced quality of life due to disabling neuropathic pain, sensory loss, gait instability, fall-related injury, and foot ulceration and amputation. The latter represents a major health and economic burden, with lower limb amputation rates related to diabetes increasing in the UK. There is a need for early diagnosis of DPN so that early management strategies may be instigated, such as achieving tight glucose control and management of cardiovascular risk factors, in an attempt to slow its progression. To this end, a one-stop microvascular assessment involving a combined eye, foot and renal screening clinic has proven feasible in the UK. Unfortunately, there are currently no approved disease-modifying therapies for DPN. Some disease-modifying agents have demonstrated efficacy, but further large trials using appropriate clinical endpoints are required before these treatments can be routinely recommended. There has been emerging evidence highlighting a reduction in vitamin D levels in cases of painful DPN and the potential for vitamin D supplementation in deficient individuals to improve neuropathic pain; however, this needs to be proved in randomised clinical trials. The use of established agents for neuropathic pain in DPN is limited by poor efficacy and adverse effects, but patient stratification using methods such as pain phenotyping are being tested to determine whether this improves the outcomes of such agents in clinical studies. In addition, innovative approaches such as the topical 8% capsaicin patch, new methods of electrical stimulation and novel therapeutic targets such as NaV1.7 offer promise for the future. This article aims to discuss the challenges of diagnosing and managing DPN and to review current and emerging lifestyle interventions and therapeutic options.

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.

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.

Associations between gabapentinoids and suicidal behaviour, unintentional overdoses, injuries, road traffic incidents, and violent crime: population based cohort study in Sweden

OBJECTIVE

To examine associations between gabapentinoids and adverse outcomes related to coordination disturbances (head or body injuries, or both and road traffic incidents or offences), mental health (suicidal behaviour, unintentional overdoses), and criminality.

DESIGN

Population based cohort study.

SETTING

High quality prescription, patient, death, and crime registers, Sweden.

PARTICIPANTS

191 973 people from the Swedish Prescribed Drug Register who collected prescriptions for gabapentinoids (pregabalin or gabapentin) during 2006 to 2013.

MAIN OUTCOME MEASURES

Primary outcomes were suicidal behaviour, unintentional overdoses, head/body injuries, road traffic incidents and offences, and arrests for violent crime. Stratified Cox proportional hazards regression was conducted comparing treatment periods with non-treatment periods within an individual. Participants served as their own control, thus accounting for time invariant factors (eg, genetic and historical factors), and reducing confounding by indication. Additional adjustments were made by age, sex, comorbidities, substance use, and use of other antiepileptics.

RESULTS

During the study period, 10 026 (5.2%) participants were treated for suicidal behaviour or died from suicide, 17 144 (8.9%) experienced an unintentional overdose, 12 070 (6.3%) had a road traffic incident or offence, 70 522 (36.7%) presented with head/body injuries, and 7984 (4.1%) were arrested for a violent crime. In within-individual analyses, gabapentinoid treatment was associated with increased hazards of suicidal behaviour and deaths from suicide (age adjusted hazard ratio 1.26, 95% confidence interval 1.20 to 1.32), unintentional overdoses (1.24, 1.19 to 1.28), head/body injuries (1.22, 1.19 to 1.25), and road traffic incidents and offences (1.13, 1.06 to 1.20). Associations with arrests for violent crime were less clear (1.04, 0.98 to 1.11). When the drugs were examined separately, pregabalin was associated with increased hazards of all outcomes, whereas gabapentin was associated with decreased or no statistically significant hazards. When stratifying on age, increased hazards of all outcomes were associated with participants aged 15 to 24 years.

CONCLUSIONS

This study suggests that gabapentinoids are associated with an increased risk of suicidal behaviour, unintentional overdoses, head/body injuries, and road traffic incidents and offences. Pregabalin was associated with higher hazards of these outcomes than gabapentin.

Rising pregabalin use and misuse in Australia: trends in utilization and intentional poisonings

BACKGROUND AND AIMS

Pregabalin is a gamma-aminobutyric acid (GABA) analogue, used to treat neuropathic pain and epilepsy. Pregabalin was registered in Australia in 2005, and subsidized publically in 2013. We aimed to describe Australian patterns of pregabalin use and intentional poisoning, and identify people potentially at high risk of misuse.

DESIGN AND SETTING

Population-based retrospective cohort study of dispensings in the 10% sample of Australian Pharmaceutical Benefits Scheme (July 2012-February 2017); intentional poisoning calls to New South Wales Poisons Information Centre (NSWPIC) (2004-2016); intentional poisonings in two Australian toxicology service databases; and poisoning fatalities in NSW coronial records (2005-2016).

PARTICIPANTS

A total of 122 572 people dispensed pregabalin, people with intentional pregabalin overdoses managed by NSWPIC and the toxicology services and pregabalin-associated deaths referred to the NSW coroner.

MEASUREMENTS

Trends in dispensing, poisoning, death; demographics and patient characteristics, proportion of users at high risk of misuse (latent class analysis, LCA) and characteristics of high-risk users.

FINDINGS

Pregabalin dispensing increased by 73 424 per year [95% confidence interval (CI) = 61726-85 121 P < 0.001] between 2013 and 2016. NSWPIC received 1158 reports of intentional pregabalin poisonings, with a 53.8% increase per year, 2005-2016 (95% CI = 44.0-64.2%, P < 0.001). We identified 88 pregabalin-associated deaths, 57.8% yearly increase (95% CI = 30.0-91.6%, P < 0.001). Patients overdosing on pregabalin commonly co-ingested opioids, benzodiazepines and illicit drugs, and had high rates of psychiatric and substance use comorbidities; 14.7% of pregabalin users were classed by the LCA as at high risk of misuse, and were more likely to be younger, male, co-prescribed benzodiazepines or opioids, have more individual prescribers and higher pregabalin strengths dispensed.

CONCLUSIONS

There has been a dramatic increase in pregabalin use, poisonings and deaths in Australia since it became subsidized publicly in 2013. One in seven Australians dispensed pregabalin appears to be at high risk of misuse.

Reports of gabapentin and pregabalin abuse, misuse, dependence, or overdose: An analysis of the Food And Drug Administration Adverse Events Reporting System (FAERS)

BACKGROUND

Reports of gabapentinoid (gabapentin and pregabalin) misuse have increased in recent years. Pharmacovigilance data from the Food and Drug Administration Adverse Event Reporting System (FAERS) provides a useful examination of adverse drug event (ADE) reporting for safety signal detection.

OBJECTIVE

This study was conducted to analyze epidemiological information on the nature and extent of gabapentin/pregabalin abuse utilizing the FAERS database.

METHODS

A query was designed utilizing SafeRx, an indexed, searchable database of FAERS data from October 2012-December 2016. All-cause and abuse-related (including abuse/misuse/dependence/overdose events) ADE reports for gabapentin and pregabalin were isolated, as well as limited demographic data. The proportional reporting ratio (PRR) was calculated to compare signal detection.

RESULTS

A total of 10,038 all-cause ADEs were reported to FAERS for gabapentin, including 576 (5.7%) abuse-related events. For pregabalin, 571 all-cause ADEs were identified, including 58 (10.2%) related to abuse. Compared to all-cause ADEs, those involved in abuse-related events were younger and more likely to be male. The PRR of pregabalin versus gabapentin abuse-related events was 1.77.

CONCLUSION

Though not traditionally thought of as drugs of abuse, over 600 cases of gabapentinoid abuse were reported in the time frame analyzed, prompting the need for further study and regulatory investigation.

Capsaicin 8% Patch Repeat Treatment in Nondiabetic Peripheral Neuropathic Pain: A 52-Week, Open-Label, Single-Arm, Safety Study

OBJECTIVES

To investigate the long-term safety and tolerability of capsaicin 8% patch repeat treatment in nondiabetic patients with peripheral neuropathic pain.

METHODS

A prospective, open-label, observational study in patients with postherpetic neuralgia, posttraumatic or postsurgical nerve injury, HIV-associated distal sensory polyneuropathy, or other peripheral neuropathic pain, and average daily pain score ≥4, who received ≤6 capsaicin 8% patch treatments over 52 weeks according to clinical need (retreatment at 9 to 12 wk intervals). Sensory testing and analgesic effectiveness were assessed using "bedside tests" and Brief Pain Inventory (question 5).

RESULTS

Overall, 306 patients received treatment. Treatment-emergent adverse events (TEAEs) and drug-related TEAEs were reported by 252 (82.4%) and 207 (67.6%) patients. Application site pain was the most common drug-related TEAE (n=112, 36.6%); no drug-related serious TEAEs were reported. Sensory category shift analyses from baseline to end of study (EoS) in patients attending at least 2 sensory visits (n=278 for all tests except warm, n=277) found sensory deterioration/loss in at least 1 modality in 50.4% (n=140); deterioration/loss in 1, 2, 3, 4, or 5 modalities occurred in 26.6% (n=74), 14.0% (n=39), 5.8% (n=16), 2.5% (n=7), and 1.4% (n=4) cases. Newly emergent hyperesthesia or allodynia was apparent in 1.1% to 3.6% of the cases (depending on modality) by EoS. Between 25.2% and 32.0% of patients reported improvement in a sensory modality by EoS. Average daily pain was 6.6 and 4.7 at baseline and month 12.

CONCLUSIONS

Generally, capsaicin 8% patch repeat treatment over 52 weeks was well tolerated, with variable alteration in sensory function and minimal chance of complete sensory loss.

Pregabalin Misuse and Abuse: A Scoping Review of Extant Literature

Prescribing of pregabalin is increasing worldwide with public health concerns centering on misuse and abuse of prescribed and diverted pregabalin. To describe and map what is known about misuse and abuse of pregabalin, a scoping review of available published literature was undertaken. A scoping review methodology was used to identify and map available literature on misuse and abuse of prescribed and diverted pregabalin. Four themes emerged on the misuse and abuse of pregabalin: (a) abuse potential, (b) prevalence of abuse, (c) risk and predisposition, and (d) consequences of abuse. Fifty-four records were reviewed and charted. Of note was the dearth of research on the topic prior to 2005, with increased interest in pregabalin abuse potential from 2010 onward. Available literature supports concern around abuse potential of pregabalin, especially among patients with a history of substance abuse. Prescribers should adopt more rational prescribing.

Pain-relieving effectiveness, quality of life and tolerability of repeated capsaicin 8% patch treatment of peripheral neuropathic pain in Scandinavian clinical practice

Context

Clinical trials have demonstrated the efficacy and safety of the capsaicin 8% patch in patients with peripheral neuropathic pain (PNP); however, few studies have assessed this treatment in a clinical practice.

Objective

To determine whether treatment and re‐treatment with the capsaicin 8% patch reduce PNP intensity in clinical practice.

Methods

Three non‐interventional, observational studies were concurrently conducted in Denmark, Norway and Sweden. Patients with probable or definite PNP received one or two treatments with the capsaicin 8% patch according to usual clinical practice. All analyses were performed on combined data.

Results

Overall, 382 and 181 patients received treatment and re‐treatment, respectively, with the capsaicin 8% patch. At the group level, a significant reduction in mean level of ‘usual pain’ intensity (Numerical Pain Rating Scale) over the last 24 h’ score was observed from baseline to Weeks 2 through 8 [−1.05 (95% confidence interval: −1.27, 0.82); p < 0.001] with 28% and 31% of patients reporting a ≥30% reduction in pain after first treatment and re‐treatment, respectively. Improvements in health‐related quality of life (EQ‐5D‐3L index) and overall health status (Patient Global Impression of Change) were observed early (Week 1) and throughout the treatment periods. Most application site reactions subsided within a week after treatment. Following treatment and re‐treatment, 57% and 71% of patients, respectively, were willing to undergo further treatment with the capsaicin 8% patch.

Conclusion

In Scandinavian clinical practice, capsaicin 8% patch treatment was associated with significant reductions in pain intensity and was well tolerated with over half of patients willing to undergo re‐treatment.

Pregabalin dispensing patterns in Amman-Jordan: An observational study from community pharmacies

Objectives

Pregabalin is currently approved for the treatment of epilepsy, generalized anxiety disorder, neuropathic pain and fibromyalgia. Rising attention to the abuse liability of pregabalin causing addictive behaviors is partially based on case reports and published literature of pregabalin used in dosages that override the approved therapeutic range. This study was conducted to provide background data regarding the abuse/misuse of pregabalin from community pharmacy in Jordan.

Methods

A prospective cross-sectional observational study design was used, which was conducted at different community pharmacies in Amman-Jordan. During the study period (November 2016-January 2017), a total 77 requests for pregabalin were observed from 14 pharmacies. A structured interview was conducted with all customers to gather information regarding their demographic and their request of pregabalin.

Results

A total of 77 pregabalin requests form 77 customers in a community pharmacy setting were observed in this study. Spinal disc herniation was the most common complaint for which the customer asked for the medication (n = 27, 35.1%). Self-medication was the most frequent method of requesting pregabalin (n = 44, 57.1%), while a total of 33 customers (42.9%) asked for the product using a prescription. During the observation period the number of customers suspected of abusing pregabalin for non-medical reason was 35 (45.5%). A total of 33 out of the 35 suspected customers (94.3%) asked for the product without a prescription, and 19/35 weren't sold due to suspicion of abuse (54.3%).

Conclusion

The study underscores the need for regulatory efforts to manage pregabalin abuse, through the addition of pregabalin containing products to the controlled drug list which can't be purchased without a prescription. Also, pharmacists and customers must be educated at a community pharmacy level regarding potential hazards of pregabalin abuse.

How addictive are gabapentin and pregabalin? A systematic review

In the last ten years, gabapentin and pregabalin have been becoming dispensed broadly and sold on black markets, thereby, exposing millions to potential side-effects. Meanwhile, several pharmacovigilance-databases have warned for potential abuse liabilities and overdose fatalities in association with both gabapentinoids. To evaluate their addiction risk in more detail, we conducted a systematic review on PubMed/Scopus and included 106 studies. We did not find convincing evidence of a vigorous addictive power of gabapentinoids which is primarily suggested from their limited rewarding properties, marginal notes on relapses, and the very few cases with gabapentinoid-related behavioral dependence symptoms (ICD-10) in patients without a prior abuse history (N=4). In support, there was no publication about people who sought treatment for the use of gabapentinoids. Pregabalin appeared to be somewhat more addictive than gabapentin regarding the magnitude of behavioral dependence symptoms, transitions from prescription to self-administration, and the durability of the self-administrations. The principal population at risk for addiction of gabapentinoids consists of patients with other current or past substance use disorders (SUD), mostly opioid and multi-drug users, who preferred pregabalin. Pure overdoses of gabapentinoids appeared to be relative safe but can become lethal (pregabalin > gabapentin) in mixture with other psychoactive drugs, especially opioids again and sedatives. Based upon these results, we compared the addiction risks of gabapentin and pregabalin with those of traditional psychoactive substances and recommend that in patients with a history of SUD, gabapentinoids should be avoided or if indispensable, administered with caution by using a strict therapeutic and prescription monitoring.

Randomized, Double-Blind, Placebo- and Active Comparator-Controlled Crossover Study Evaluating the Abuse Potential of the Antiepileptic Drug Lacosamide in Healthy Recreational Drug Users

PURPOSE

This phase 1, randomized, double-blind, placebo- and active comparator-controlled crossover study assessed the abuse potential of the antiepileptic drug, lacosamide.

METHODS

After a qualification phase, 38 healthy, recreational central nervous system-depressant users were randomized to treatment sequences comprising single oral therapeutic (200 mg) and supratherapeutic (800 mg) doses of lacosamide, alprazolam (1.5 and 3 mg), and placebo. Subjective effects were assessed for 24 hours following each dose using a range of scales, with a 5- to 9-day washout between treatments.

FINDINGS

Mean subjective effects for 200 mg lacosamide were statistically similar to placebo and significantly lower than with alprazolam for most end points. Lacosamide 800 mg elicited transient, statistically significant positive effects compared with placebo, but also persistent Bad Drug Effects including statistically greater maximum effect (Emax) scores for Nausea and Dysphoria compared with other treatments (P < 0.0002). Consistent with this, the 800 mg lacosamide dose showed a significantly lower "at this moment" Drug Liking visual analog scale (VAS) Emax compared with 3 mg alprazolam, but was not different from 1.5 mg alprazolam (73.1/100, 85.4/100, and 78.9/100, respectively, where 50 is neutral). Overall Drug Liking VAS and Take Drug Again VAS Emax for 800 mg lacosamide were not significantly different from placebo and were lower than those for both alprazolam doses (P < 0.0001).

IMPLICATIONS

These results suggest that in recreational central nervous system-depressant users, lacosamide has detectable abuse-related subjective effects, but a relatively low potential for abuse compared with alprazolam. These findings contributed toward placement of lacosamide into Schedule V of the US Controlled Substances Act.

WITHDRAWN: Anticonvulsants for fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a clinically well-defined chronic condition of unknown aetiology characterised by chronic widespread pain that often co-exists with sleep problems and fatigue. People often report high disability levels and poor health-related quality of life (HRQoL). Drug therapy focuses on reducing key symptoms and disability, and improving HRQoL. Anticonvulsants (antiepileptic drugs) are drugs frequently used for the treatment of chronic pain syndromes.

OBJECTIVES

To assess the benefits and harms of anticonvulsants for treating FM symptoms.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 8, 2013), MEDLINE (1966 to August 2013), PsycINFO (1966 to August 2013), SCOPUS (1980 to August 2013) and the reference lists of reviewed articles for published studies and www.clinicaltrials.gov (to August 2013) for unpublished trials.

SELECTION CRITERIA

We selected randomised controlled trials of any formulation of anticonvulsants used for the treatment of people with FM of any age.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data of all included studies and assessed the risks of bias of the studies. We resolved discrepancies by discussion.

MAIN RESULTS

We included eight studies: five with pregabalin and one study each with gabapentin, lacosamide and levetiracetam. A total of 2480 people were included into anticonvulsants groups and 1099 people in placebo groups. The median therapy phase of the studies was 13 weeks. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM. The amount and quality of evidence was sufficient to draw definite conclusions on the efficacy and safety of pregabalin in FM. Therefore, we focused on our interpretation of the evidence for pregabalin due to our greater certainty about its effects and its greater relevance to clinical practice. All pregabalin studies had a low risk of bias. Reporting a 50% or greater reduction in pain was more frequent with pregabalin use than with a placebo (risk ratio (RR) 1.59; 95% confidence interval (CI) 1.33 to 1.90; number needed to treat for an additional beneficial outcome (NNTB) 12; 95% CI 9 to 21). The number of people who reported being 'much' or 'very much' improved was higher with pregabalin than with placebo (RR 1.38; 95% CI 1.23 to 1.55; NNTB 9; 95% CI 7 to 15). Pregabalin did not substantially reduce fatigue (SMD -0.17; 95% CI -0.25 to -0.09; 2.7% absolute improvement on a 1 to 50 scale) compared with placebo. Pregabalin had a small benefit over placebo in reducing sleep problems by 6.2% fewer points on a scale of 0 to 100 (standardised mean difference (SMD) -0.35; 95% CI -0.43 to -0.27). The dropout rate due to adverse events was higher with pregabalin use than with placebo use (RR 1.68; 95% CI 1.36 to 2.07; number needed to treat for an additional harmful outcome (NNTH) 13; 95% CI 9 to 23). There was no significant difference in serious adverse events between pregabalin and placebo use (RR 1.03; 95% CI 0.71 to 1.49). Dizziness was reported as an adverse event more frequently with pregabalin use than with placebo use (RR 3.77; 95% CI 3.06 to 4.63; NNTH 4; 95% CI 3 to 5).

AUTHORS' CONCLUSIONS

The anticonvulsant, pregabalin, demonstrated a small benefit over placebo in reducing pain and sleep problems. Pregabalin use was shown not to substantially reduce fatigue compared with placebo. Study dropout rates due to adverse events were higher with pregabalin use compared with placebo. Dizziness was a particularly frequent adverse event seen with pregabalin use. At the time of writing this review, pregabalin is the only anticonvulsant drug approved for treating FM in the US and in 25 other non-European countries. However, pregabalin has not been approved for treating FM in Europe. The amount and quality of evidence were insufficient to draw definite conclusions on the efficacy and safety of gabapentin, lacosamide and levetiracetam in FM.

Pregabalin Use Among Users of Illicit Drugs: A Cross-Sectional Survey in Southern Germany

BACKGROUND

The antiepileptic drug pregabalin is one of the best-selling pharmaceutical products worldwide. There are increasing concerns about its potential for misuse and dependence especially among patients with former or current substance use disorders (SUDs).

OBJECTIVE

Our objective was to clarify the extent and pattern of pregabalin use as well as motives and predictors in this population.

METHODS

We conducted a cross-sectional study with patients on a detoxification ward for illicit drugs at the Center for Psychiatry, Südwürttemberg, Ravensburg in southern Germany from August 2012 until July 2013. We used an extensive questionnaire, part of the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) Axis I Disorders (SCID-I) and urine samples.

RESULTS

Of the 253 participating patients, 56% had used pregabalin at least once. Of these, 92% had acquired it at least in part from illegal sources. The main motives for the use of pregabalin were the attenuation of opioid withdrawal symptoms, the augmentation of other psychotropic substances, and the psychotropic effects of pregabalin itself. Predictors for pregabalin use were opioid and sedative use as well as younger age. The criteria of dependency according to DSM-IV was met by 11% of pregabalin users and 13% of urine samples were positive for pregabalin.

CONCLUSIONS

Use of pregabalin is common among users of illicit drugs in large parts of southern Germany, with motives for use, acquisition, and mode of use suggesting misuse. The mode of use, especially intake of high doses and concomitant use of other drugs, poses a serious risk to this population, including the development of dependency.