Pregabalin for the Treatment of Drug and Alcohol Withdrawal Symptoms: A Comprehensive Review

Phenibut: Review and Pharmacologic Approaches to Treating Withdrawal

β-Phenyl-γ-aminobutyric acid (phenibut) is an analog of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) that was first synthesized in Russia in the early 1960s. It is marketed as a nootropic (smart drug) to improve cognitive performance, and to treat generalized and social anxiety, insomnia, and alcohol withdrawal. The use of phenibut is legal in the USA and it is widely available online without a prescription. Increased public awareness of phenibut has led to a growing number of reports of acute intoxication and withdrawal. In this review, we describe the pharmacology of phenibut, the presentation and management of acute intoxication, and regulatory issues, placing particular emphasis on the treatment of acute withdrawal, for which there are no comparative studies. Among 29 cases of phenibut withdrawal, patients were successfully treated with baclofen, benzodiazepines, and phenobarbital, as individual agents or in various combinations. Ancillary medications included antipsychotics, dexmedetomidine, gabapentin, and pregabalin. After stabilization, a number of patients did well on baclofen tapers, whereas others were weaned off benzodiazepines or phenobarbital. Phenobarbital may be preferred over baclofen, or used as an added agent, in patients at risk for seizures. As long as phenibut remains legal, cases of phenibut intoxication and withdrawal are likely to increase. As urine or plasma drug screening for phenibut is not widely available, it is vital that clinicians obtain a detailed medication history in patients presenting to the emergency department with nonspecific symptoms that may represent phenibut intoxication or withdrawal. Further, clinicians may wish to consult an addiction specialist or toxicologist in these situations.

Role of glycogen synthase kinase-3β in dependence and abuse liability of alcohol

BACKGROUND

Alcohol is a major abused drug worldwide that contributes substantially to health and social problems. These problems result from acute alcohol overuse as well as chronic use, leading to alcohol use disorder (AUD). A major goal of this field is to establish a treatment for alcohol abuse and dependence in patients with AUD. The central molecular mechanisms of acute alcohol actions have been extensively investigated in rodent models.

AIMS

One of the central mechanisms that may be involved is glycogen synthase kinase-3β (GSK-3β) activity, a key enzyme involved in glycogen metabolism but which has crucial roles in numerous cellular processes. Although the exact mechanisms leading from acute alcohol actions to these chronic changes in GSK-3β function are not yet clear, GSK-3β nonetheless constitutes a potential therapeutic target for AUD by reducing its function using GSK-3β inhibitors. This review is focused on the correlation between GSK-3β activity and the degree of alcohol consumption.

METHODS

Research articles regarding investigation of effect of GSK-3β on alcohol consumption in rodents were searched on PubMed, Embase, and Scopus databases using keywords "glycogen synthase kinase," "alcohol (or ethanol)," "intake (or consumption)," and evaluated by changes in ratios of pGSK-3βSer9/pGSK-3β.

RESULTS

In animal experiments, GSK-3β activity decreases in the brain under forced and voluntary alcohol consumption while GSK-3β activity increases under alcohol-seeking behavior.

CONCLUSIONS

Several pieces of evidence suggest that alterations in GSK-3β function are important mediators of chronic ethanol actions, including those related to alcohol dependence and the adverse effects of chronic ethanol exposure.

Pregabalin use in forensic hospitals and prisons in German speaking countries-a survey study of physicians

Background

Pregabalin is a gamma-aminobutyric acid (GABA) analog that was approved in the EU in 2004 for the treatment of neuropathic pain, generalized anxiety disorder and epilepsy. Since its introduction, pregabalin abuse and misuse has increased significantly. In Switzerland, clinical reports suggest that pregabalin misuse is common among patients in forensic hospitals and prisons. However, data on pregabalin use is scarce, especially in these settings. Therefore, we conducted a study to explore patterns of pregabalin use among prison and forensic patients.

Methods

We used a questionnaire to survey physicians working in prison and forensic medicine in German-speaking countries. A total of 131 responses were received.

Results

According to the physicians' subjective assessment, 82.5% of them had observed a recent increase in pregabalin use by their patients and 89.1% of them reported that their patients requested pregabalin without a clear medical indication. Patients misusing pregabalin in combination with other illicit substances were observed by 93.3% of the physicians surveyed. According to 73.5% of the physicians surveyed, they had already encountered patients on pregabalin doses of more than 600 mg/day (the maximum recommended daily dose); the highest dose reported was 4,200 mg/day. According to 85.0% of physicians surveyed, they have observed patients experiencing withdrawal symptoms from pregabalin, with the most commonly reported symptoms being displeasure and high aggression. Regarding the nationality of pregabalin-misusing patients, 58.3% of the interviewed physicians reported to be rather in contact with foreign patients, mainly from Northwest Africa (Maghreb). Only 45.0% of the surveyed physicians prescribe pregabalin. Among patients who developed behavioral problems while taking pregabalin, none of the physicians (0.0%) showed a tendency to continue pregabalin at the same dose; all respondents chose to reduce/substitute/discontinue.

Conclusion

Our study has provided confirmatory evidence that the use of pregabalin presents a significant issue in forensic and prison medicine across German-speaking countries. Prescribing pregabalin in this field can compound use disorder problems and exacerbate challenges in daily life for those in forensic institutions or prisons. It is necessary that all physicians who prescribe pregabalin are clearly informed about the management (including the risks) of this drug.

Progress on transition metal catalyzed asymmetric hydroesterification, hydrocarboxylation, and hydroamidation reactions of olefins

Hydrocarboxylation, hydroesterification, and hydroamidation of olefins are fundamental transformations in organic synthesis. Asymmetric processes for these transformations provide an effective and straightforward approach to optically active carboxylic acids and their derivatives, which are highly useful compounds in pharmaceuticals, materials, fine chemicals, etc. This review provides a brief summary of the development of asymmetric hydroesterification, hydrocarboxylation, and hydroamidation with CO and its surrogates.

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.

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.

[Pharmacotherapy of alcohol withdrawal: update and new developments]

Bislang sind nur wenige Medikamente zur pharmakologischen Rückfallprophylaxe der Alkoholabhängigkeit zugelassen. Neben dem in Deutschland nicht mehr vertriebenen Disulfiram sind es die Opioidantagonisten Naltrexon und Nalmefen sowie das vermutlich über glutamaterge Neurone wirkende Acamprosat. Baclofen und γ‑Hydroxybutyrat (GHB) sind in einzelnen Ländern zugelassen. Wirkstoffe wie z. B. Vareniclin, Gabapentin und Topiramat können für die Rückfallprophylaxe der Alkoholabhängigkeit von Interesse sein, jedoch ist bislang keine Zulassung erfolgt. Vor dem Hintergrund der zur Revision anstehenden S3-Leitlinie zur Diagnose und Behandlung alkoholbezogener Störungen wird der heutige Kenntnisstand zur Pharmakotherapie der Alkoholabhängigkeit dargestellt.

Gabapentinoid Benefit and Risk Stratification: Mechanisms Over Myth

INTRODUCTION

Recent years have seen a dramatic escalation of off-label prescribing for gabapentin and pregabalin (gabapentinoids) owing in part to generic versions of each being released over the past two decades, but also in part as a response to increasing calls for multimodal and non-opioid pain management strategies. In this context, several recent articles have been published alleging widespread misuse, with speculations on the unappreciated addictive potential of the gabapentinoid class of drugs. Reports of a 1% population-level abuse prevalence stem from a single internet survey in the UK, and the vanishingly small adverse event outcomes data do not support such frequency. In this targeted narrative review, we aim to disabuse pain physicians and other clinicians, pharmacists, and policymakers of both the positive and negative myths concerning gabapentinoid medications.

RESULTS

Gabapentinoids inhibit the joint action of voltage-gated calcium channel (VGCC) α2δ subunits in conjunction with the n-methyl-D-aspartate (NMDA) receptor, with subsequent downregulation of VGCC expression and excitatory neurotransmitter release, and possibly synaptogenesis as well, through actions on thrombospondins. These activities reduce the likelihood of central sensitization, which explains in part the efficacy of the gabapentinoids in the management of neuropathic pain. Gabapentinoids also facilitate slow-wave sleep, a relatively rare phenomenon among central nerve system-acting agents, which is also thought to explain some of the therapeutic benefit of the class in conditions such as fibromyalgia. The number needed to treat to see benefit overlaps that of the nonsteroidal anti-inflammatory drugs, but with a considerably improved safety profile. Along these lines, in the context of over 50 million prescriptions per year in the USA alone, the gabapentinoids display remarkably low risk, including risks of misuse, abuse, and dependence. Furthermore, the neurobiology of these agents does not lend plausibility to the allegations, as they have never been shown to elicit dopaminergic activity within the nucleus accumbens, and in addition likely confer a "negative-feedback loop" for habituation and dependence by serving as functional NMDA antagonists, possibly through their actions on thrombospondins. Clinical and epidemiological addictionology studies corroborate the lack of any significant addictive potential of the gabapentinoids, and these drugs are increasingly being used in the treatment of addiction to other substances, with excellent results and no evidence of cross-addiction. However, among individuals with other substance use disorders and, in particular opioid use disorder, there are consistent data showing misuse of gabapentinoids in up to 20% of this population. Although there are allegations of using gabapentinoids to amplify the hedonic effects of opioids, the vast majority of misuse events appear to occur in an attempt to ameliorate opioid withdrawal symptoms. Furthermore, rare but potentially serious respiratory depression may occur, again amplified in the context of opioid or other sedative use. Careful risk:benefit assessment and stratification are warranted when prescription of a gabapentinoid is under consideration, in particular among individuals using opioids.

CONCLUSIONS

Gabapentinoids remain a vital tool in the pain physician's multimodal armamentarium, but these drugs may not be effective in every clinical situation. Individuals with central sensitization and pain associated with slow-wave sleep deficits and potentially persons with comorbid addictions may benefit the most. The gabapentinoids appear to possess no addictive potential on their own, based on laboratory and clinical data, but they may be abused by persons with opioid use disorders; consequently, cautious risk stratification must take place.

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.

Neurochemical Evidence of Preclinical and Clinical Reports on Target-Based Therapy in Alcohol Used Disorder

Alcohol use disorder (AUD) is a chronic relapsing disorder, which enforces a person to compulsively seek alcohol, restricting control over alcohol intake leads to emergence of an undesired emotional state during abstinence. There are recent advances for better understanding of neurocircuitry involved in the pathophysiology of AUD. Alcohol interaction with neuronal membrane proteins results in changes in neuronal circuits. It is also linked with the potential medication and their clinical validation concerning their pharmacological targets for alcoholic abstinence. This review covers research work from the past few decades on the therapeutic advances on treatment of alcohol dependence; further detailing the fundamental neurochemical mechanisms after alcohol administration. It also covers interaction of alcohol with GABAergic, glutaminergic, dopaminergic, serotonergic and opioid systems. This review further elaborated the neurobiology of noradrenergic, cholinergic and cannabinoid systems and their interaction with AUD. Elaborative information of potential drug targets under current exploration for AUD treatment with their mechanisms are reported here along with clinical outcomes and the associated side effects.

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.

Clinical Trials for Opioid Use Disorder

This chapter describes recent clinical trials for opioid use disorder (OUD), an area that has rapidly accelerated in response to the opioid overdose crisis in the USA and newly appropriated funding. Trials involve a wide range of compounds including cannabinoids and psychedelics, new and existing compounds targeting domains emerging from addiction neuroscience, agents repurposed from other indications, and novel strategies including vaccines, enzymes, and other biologicals. In parallel, new formulations of existing compounds offer immediate promise, as do a variety of web-based interventions and smartphone-delivered apps. Trials focused on implementing existing effective interventions in mainstream healthcare settings, and others focused on special populations, e.g., adolescents, criminal justice, pregnant women, native Americans, etc., have the potential to vastly expand treatment in the near term. Given the range of ongoing and recent trials, this chapter is not intended to be an exhaustive review but rather to present an overview of approaches within the framework of the opioid treatment cascade and the context of current OUD pharmacotherapies.

WFSBP * and IAWMH ** Guidelines for the treatment of alcohol use disorders in pregnant women

OBJECTIVES

These practice guidelines for the treatment of alcohol use disorders during pregnancy were developed by members of the International Task Force of the World Federation of Societies of Biological Psychiatry and the International Association for Women's Mental Health.

METHODS

We performed a systematic review of all available publications and extracted data from national and international guidelines. The Task Force evaluated the data with respect to the strength of evidence for the efficacy and safety of each medication.

RESULTS AND DISCUSSION

There is no safe level of alcohol use during pregnancy. Abstinence is recommended. Ideally, women should stop alcohol use when pregnancy is planned and, in any case, as soon as pregnancy is known. Detecting patterns of alcohol maternal drinking should be systematically conducted at first antenatal visit and throughout pregnancy. Brief interventions are recommended in the case of low or moderate risk of alcohol use. Low doses of benzodiazepines, for the shortest duration, may be used to prevent alcohol withdrawal symptoms when high and chronic alcohol intake is stopped and hospitalisation is recommended. Due to the low level of evidence and/or to low benefit/risk ratio, pharmacological treatment for maintenance of abstinence should not be used during pregnancy. At birth, foetal alcohol spectrum disorders must be searched for, and alcohol metabolites should be measured in meconium of neonates in any doubt of foetal alcohol exposure.

Assessment of Pregabalin Use by Hair Testing

BACKGROUND

The detection and analysis of drugs in hair has progressively emerged as a consequence of the enhanced sensitivity of analytical techniques used in forensic toxicology; a greater advantage in using this matrix respect to classical ones (i.e., urine and blood) is an easier and noninvasive sample collection, even when the careful supervision of law-enforcement officers is required to avoid the risk that the sample may be adulterated or replaced. Moreover, according to the length of the hair, the history of drug exposure can be retrospectively monitored from few weeks up to months or years since sample collection.

OBJECTIVE

Given the potential negative effects of pregabalin, an antiepileptic and analgesic drug with a high risk of misuse and abuse, the laboratory was asked to test for the drug in hair.

METHOD

A new ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry was developed. The method involves incubation of 25 mg of cut hair in acetonitrile for 2 h in an ultrasonic bath and separation on an Acquity HSS C18 column (150 × 2.1 mm × 1.8 µm) maintained at 50°C in a thermostatically controlled oven. A gradient elution was performed.

RESULTS

The method was fully validated according to international standards. The limit of quantitation of the test was 10 pg/mg. Five authentic cases of pregabalin in hair segments were tested using the method and the results were in the range 17-1487 pg/mg.

CONCLUSION

This new method was found suitable to monitor both patients under pregabalin therapy and dependent subjects.

Pharmacotherapy for Alcohol Use Disorder

Alcohol use disorder is a common, destructive, and undertreated disease. As understanding of alcohol use disorder has evolved, so has our ability to manage patients with pharmacotherapeutic agents in addition to nondrug therapy, including various counseling strategies. Providers now have a myriad of medications, both approved and not approved by the US Food and Drug Administration, to choose from and can personalize care based on treatment goals, comorbidities, drug interactions, and drug availability. This review explores these treatment options and offers the prescriber practical advice regarding when each option may or may not be appropriate for a specific patient.

Addiction-related interactions of pregabalin with morphine in mice and humans: reinforcing and inhibiting effects

The gabapentinoid pregabalin is a rapid-acting anxiolytic and analgesic, possibly suitable in supervised opioid detoxification. However, clinicians have been cautious in using it because of its unknown addictive risk and rising number of mortalities after pregabalin self-medication in opioid abusers. Here, we studied interactions of pregabalin and morphine on reward functions of the dopamine system in mice and the efficacy of pregabalin on withdrawal in opioid addicts. After the treatment of mice with pregabalin and morphine, we used electrophysiology to study neuroplasticity in midbrain slices, self-administration and conditioned place preference tests to investigate the rewarding potential of pregabalin and naloxone-precipitated morphine withdrawal to evaluate opioid withdrawal symptoms. Further, we ran a pilot single-blind, randomized, controlled trial (34 heroin addicts) to evaluate the efficacy and safety of pregabalin in the treatment of opioid withdrawal syndrome. Pregabalin alone did not induce glutamate receptor neuroplasticity of dopamine neurons in the ventral tegmental area, but pre-treatment with pregabalin suppressed morphine-induced neuroplasticity, hyperlocomotion and morphine self-administration. Pregabalin administration after chronic morphine exposure failed to induce any rewarding effects. Instead, pregabalin suppressed withdrawal symptoms in both morphine-treated mice and opioid addicts and was well tolerated. Intriguingly, pregabalin administration after a low dose of morphine strongly facilitated ventral tegmental area neuroplasticity and led to increased conditioned place preference. Pregabalin appears to have the efficacy to counteract both reinforcing and withdrawal effects of opioids, but it also has a potentiating effect when given to mice with existing opioid levels.

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.

Trauma exposure interacts with the genetic risk of bipolar disorder in alcohol misuse of US soldiers

OBJECTIVE

To investigate whether trauma exposure moderates the genetic correlation between substance use disorders and psychiatric disorders, we tested whether trauma exposure modifies the association of genetic risks for mental disorders with alcohol misuse and nicotine dependence (ND) symptoms.

METHODS

High-resolution polygenic risk scores (PRSs) were calculated for 10 732 US Army soldiers (8346 trauma-exposed and 2386 trauma-unexposed) based on genome-wide association studies of bipolar disorder (BD), major depressive disorder, and schizophrenia.

RESULTS

The main finding was a significant BD PRS-by-trauma interaction with respect to alcohol misuse (P = 6.07 × 10^-3 ). We observed a positive correlation between BD PRS and alcohol misuse in trauma-exposed soldiers (r = 0.029, P = 7.5 × 10^-3 ) and a negative correlation in trauma-unexposed soldiers (r = -0.071, P = 5.61 × 10^-4 ). Consistent (nominally significant) result with concordant effect, directions were observed in the schizophrenia PRS-by-trauma interaction analysis. The variants included in the BD PRS-by-trauma interaction showed significant enrichments for gene ontologies related to high voltage-gated calcium channel activity (GO:0008331, P = 1.51 × 10^-5 ; GO:1990454, P = 4.49 × 10^-6 ; GO:0030315, P = 2.07 × 10^-6 ) and for Beta1/Beta2 adrenergic receptor signaling pathways (P = 2.61 × 10^-4 ).

CONCLUSIONS

These results indicate that the genetic overlap between alcohol misuse and BD is significantly moderated by trauma exposure. This provides molecular insight into the complex mechanisms that link substance abuse, psychiatric disorders, and trauma exposure.

GC-MS/MS detects potential pregabalin abuse in susceptible subjects' hair

Pregabalin, a GABA analogue, binds to the alpha 2 delta subunit of voltage-dependent calcium channels. It is recognised as efficacious in pathologies such as epilepsy, neuropathic pain, and anxiety disorders. Since pregabalin prescriptions have increased worldwide, reports of its abuse have been accumulating, mainly in patients with opioid abuse disorders. The present study investigated potential pregabalin abuse by means of hair analysis, a matrix that provides valuable retrospective information. Half of the pool of 280 susceptible patients had been occasional drug users and were being monitored for driving licence renewals. The other 140 patients had a history of opiate dependency and were monitored to assess compliance with methadone therapy. In view of determining pregabalin in hair samples, it was extracted in methanol, successfully derivatised to give the ethyl chloroformate derivative, and finally pregabalin was analysed by gas chromatography-tandem mass spectrometry. Selectivity, linearity, limit of detection, limit of quantification, recovery, intra- and inter-day precision, and accuracy of the quantification procedure were appraised. Pregabalin limits of detection and quantification were 30 pg/mg and 50 pg/mg, respectively. We found 10.7% of hair samples from methadone patients and 4.29% from occasional drug users were positive to pregabalin without medical prescription. The mean pregabalin concentration in hair was higher than in consumers with medical indications (1.45 ng/mg vs 0.74 ng/mg). These results suggest that pregabalin possesses a significant abuse potential particularly among individuals attending opiate dependence services and that pregabalin abuse is a serious emerging issue, which should be carefully monitored.

Gabapentin for the treatment of alcohol use disorder

INTRODUCTION

Alcohol misuse is the fifth leading risk factor for premature death and disability worldwide. Fewer than 10% of afflicted Americans receive pharmacological treatment for alcohol use disorder. Gabapentin is a calcium channel GABAergic modulator that is widely used for pain. Studies showing reduced drinking and decreased craving and alcohol-related disturbances in sleep and affect in the months following alcohol cessation suggest therapeutic potential for alcohol use disorder. Areas covered: Human laboratory and clinical studies assessing gabapentin for alcohol use disorder are reviewed. Data were obtained by searching for English peer-reviewed articles on PubMed, reference lists of identified articles, and trials registered on clinicaltrials.gov. Additionally, the mechanism of action of gabapentin specific to alcohol use disorder, and studies of gabapentin for alcohol withdrawal and non-alcohol substance use disorders are summarized. Expert opinion: Alcohol use disorder represents a challenge and large, unmet medical need. Evidence from single-site studies lend support to the safety and efficacy of gabapentin as a novel treatment for alcohol use disorder, with unique benefits for alcohol-related insomnia and negative affect, relative to available treatments. Proprietary gabapentin delivery systems may open a path to pivotal trials and registration of gabapentin as a novel treatment for alcohol use disorder.

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.

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.

Pregabalin Misuse and Abuse in Jordan: a Qualitative Study of User Experiences

Pregabalin is currently approved for the treatment of epilepsy, generalized anxiety disorder, neuropathic pain, and fibromyalgia. A qualitative study was undertaken in Jordan, where concerns have been raised about its unprescribed availability in community pharmacies and thereby its abuse. Semi-structured interviews were conducted with all patients with a history of pregabalin use in two Jordanian addiction treatment centers. All were male patients aged 21–30 years (n = 11). The majority was poly-drug abusers and had a previous history of substance abuse (tramadol, Captagon, synthetic cannabinoids, and marijuana). Six key themes emerged from a content textual analysis which centered on pregabalin and other drugs; the pregabalin effect; poly-pharming and pregabalin intoxication; trajectories, patterns, and routes of administration; dependence and withdrawal; and sourcing of pregabalin. The study underscores the need for continued pharmacovigilance to manage and address suspected abuse, along with community pharmacist and patient education regarding abuse liability and related harms.