Phenibut (4-amino-3-phenyl-butyric acid): Availability, prevalence of use, desired effects and acute toxicity

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.

Monitoring the use of novel psychoactive substances in Australia by wastewater-based epidemiology

Users of novel psychoactive substances (NPS) are at risk, due to limited information about the toxicity and unpredictable effects of these compounds. Wastewater-based epidemiology (WBE) has been used as a tool to provide insight into NPS use at the population level. To understand the preferences and trends of NPS use in Australia, this study involved liquid chromatography mass spectrometry analysis of wastewater collected from Australian states and territories from February 2022 to February 2023. In total, 59 different NPS were included across two complementary analytical methods and covered up to 57 wastewater catchments over the study. The NPS detected in wastewater were 25-B-NBOMe, buphedrone, 1-benzylpiperazine (BZP), 3-chloromethcathinone, N,N-dimethylpentylone (N,N-DMP), N-ethylheptedrone, N-ethylpentylone, eutylone, 4F-phenibut, 2-fluoro deschloroketamine, hydroxetamine, mephedrone, methoxetamine, methylone, mitragynine, pentylone, phenibut, para-methoxyamphetamine (PMA), alpha-pyrrolidinovalerophenone (α-PVP) and valeryl fentanyl. The detection frequency for these NPS ranged from 3 % to 100 % of the sites analysed. A noticeable decreasing trend in eutylone detection frequency and mass loads was observed whilst simultaneously N,N-DMP and pentylone increased over the study period. The emergence of some NPS in wastewater pre-dates other sources of monitoring and provides further evidence that WBE can be used as an additional early warning system for alerting potential NPS use.

A systematic review of phenibut withdrawal focusing on complications, therapeutic approaches, and single substance versus polysubstance withdrawal

INTRODUCTION

Phenibut is an unregulated supplement that acts primarily as a gamma-aminobutyric acid type B receptor agonist. Use of phenibut can lead to dependence and subsequent withdrawal when use is stopped. Phenibut withdrawal can cause severe symptoms such as delirium, hallucinations, and seizures. The purpose of this systematic review is to characterize the natural history of phenibut withdrawal and summarize treatment strategies published in the literature.

METHODS

A systematic review was conducted using the preferred reporting items for systematic reviews and meta-analyses checklist. English language peer-reviewed articles or conference abstracts in humans describing phenibut withdrawal after cessation of use were included. Databases (Ovid/MEDLINE, Web of Science, and Science Direct) and references of included articles were searched. Case reports were appraised using the Joanna Briggs Institute critical appraisal checklist for case reports. Patient demographics and key outcomes, including withdrawal characteristics and treatment characteristics, were collected into a predefined data collection sheet by six independent reviewers.

RESULTS

Search results yielded 515 articles of which 25 were included. All articles were case reports or published conference abstracts. All of the cases (100 percent) involved male patients and the median age was 30 years, (interquartile range 23.5-34 years, range 4 days-68 years). The median daily phenibut dose prior to experiencing withdrawal was 10 g (interquartile range 4.75-21.5 g, range 1-200 g). The shortest duration of phenibut use (2-3 g daily) prior to withdrawal was one week. Withdrawal symptoms occurred as quickly as two hours after the last phenibut dose. Sixteen patients (64 percent) reported progression of withdrawal severity within the first 24 hours of healthcare contact. Seizures were reported in two patients (8 percent), intubation in six patients (24 percent), and intensive care unit admission in 11 patients (44 percent). Withdrawal patterns and outcomes were similar in those using phenibut alone and those with comorbid polysubstance use. Withdrawal treatment strategies varied widely. Only three cases (12 percent) were managed outpatient and all three utilized a phenibut tapering strategy. All patients undergoing medication-assisted abstinence were admitted inpatient for symptom management and received a drug that acts on gamma-aminobutyric acid receptors. The most commonly used medication was a benzodiazepine, reported in 17 cases (68 percent). Nineteen patients (76 percent) required at least two drug therapies to manage symptoms. Baclofen was used in 15 cases (60 percent), primarily in conjunction with gamma-aminobutyric acid type A agonists (12 of 15 cases) or as monotherapy during a phenibut taper (two of 15 cases). Two patients using baclofen monotherapy outpatient, after initial stabilization with multiple drug classes, reported adverse effects. One patient had a seizure and the other experienced recurrent withdrawal symptoms, returned to using phenibut, and was admitted to a hospital for withdrawal symptom management with benzodiazepines.

LIMITATIONS

This review is subject to several limitations. Due to the manual nature of article selection, it is possible relevant articles may not have been included. As the entire data set is comprised of case reports it may suffer from publications bias. Outcomes and meaningful conclusions from specific treatment strategies were rarely available because of the heterogeneous nature of case reports. It is possible those reporting only phenibut use were actually using multiple substances. The doses of phenibut a user believed they were taking may be different from what was present in the unregulated product.

CONCLUSIONS

Phenibut withdrawal appears to have a range of severity. It is important to recognize that patients undergoing phenibut abstinence may have progressive symptom worsening during early withdrawal. All published cases of abrupt phenibut abstinence were admitted inpatients for symptom management. Benzodiazepines or barbiturates with adjunctive baclofen appear to be the most commonly used drugs for moderate to severe withdrawal. Outpatient management via slow phenibut tapers with or without adjunctive gamma-aminobutyric acid agonist therapy may be successful. However, there is no standard treatment, and consultation with experts (e.g., toxicologists, addiction specialists) experienced in managing withdrawal syndromes is recommended. Significant study is warranted to develop methods of triaging phenibut withdrawal (e.g., severity scoring, inpatient versus outpatient management) and creating optimal treatment regimens.

Growing Utilization of Radical Chemistry in the Synthesis of Pharmaceuticals

Our current unhealthy lifestyle and the exponential surge in the population getting affected by a variety of diseases have made pharmaceuticals or drugs an imperative part of life, making the development of innovative strategies for drug discovery or the introduction of refined, cost-effective and modern technologies for the synthesis of clinically used drugs, a need of the hour. Ever since their discovery, free radicals and radical cations or anions as reactive intermediates have captivated the chemists, resulting in an exceptional utilization of these moieties throughout the field of chemical synthesis, owing to their unprecedented and widespread reactivity. Sticking with the idea of not judging the book by its cover, despite the conventional thought process of radicals being unstable and difficult to control entities, scientists and academicians around the globe have done an appreciable amount of work utilizing both persistent as well as transient radicals for a variety of organic transformations, exemplifying them with the synthesis of significant biologically active pharmaceutical ingredients. This review truly accounts for the organic radical transformations including radical addition, radical cascade cyclization, radical/radical cross-coupling, coupling with metal-complexes and radical cations coupling with nucleophiles, that offers fascinating and unconventional approaches towards the construction of intricate structural frameworks of marketed APIs with high atom- and step-economy; complementing the otherwise employed traditional methods. This tutorial review presents a comprehensive package of diverse methods utilized for radical generation, featuring their reactivity to form critical bonds in pharmaceutical total synthesis or in building key starting materials or intermediates of their synthetic journey, acknowledging their excellence, downsides and underlying mechanisms, which are otherwise poorly highlighted in the literature. Despite great achievements over the past few decades in this area, many challenges and obstacles are yet to be unraveled to shorten the distance between the academics and the industry, which are all discussed in summary and outlook.

Reasons for use and experiences of using phenibut, a mixed methods analysis of online reports

Background: Phenibut is a drug similar in structure to gabapentin and pregabalin. It is available online without prescription, often marketed as a dietary supplement or amino acid derivative. Little is known about phenibut use despite its increased popularity in the United States over the last decade.Objective: To clarify reasons for taking phenibut, circumstances, and effects of use.Methods: Reports of phenibut, gabapentin, and pregabalin use were downloaded from a publicly-available database, Erowid.org. A mixed methods approach utilizing qualitative content analysis was used.Results: Of 229 reports, 211 were from male authors. People usually purchased phenibut online and reportedly used it for recreation, to manage a medical or psychiatric problem (primarily insomnia, anxiety), as a substitute for other drugs (especially benzodiazepines), to manage withdrawal from another substance (including benzodiazepines, opioids), and/or for performance enhancement. While it shared many reported effects with pregabalin and gabapentin such as anxiolysis, increased talkativeness, and impaired motor coordination, reports of gastrointestinal distress and sedation were more commonly attributed to phenibut. Several people reported difficulty in restricting their use and managing withdrawal.Conclusions: Phenibut reports suggest that phenibut may have some benefits for some people. Use also, however, carries risks of adverse effects, a potentially dangerous withdrawal syndrome, and addiction. Not dissimilar to unprescribed gabapentin or pregabalin, self-medication is a common motive for phenibut use. Physicians should continue to ask their patients about use of any non-prescribed medications, dietary supplements, or "amino acid derivatives."Abbreviation: PWUPh: people who use phenibut; PWUG: people who use gabapentin; PWUPr: people who use pregabalin.

Phenibut toxicosis in a dog

OBJECTIVE

To describe the successful treatment of severe neurological and cardiovascular abnormalities in a dog following ingestion of the neuropsychotropic drug, phenibut.

CASE SUMMARY

A 2-year-old neutered male Weimaraner was found unresponsive and laterally recumbent in his urine after ingesting approximately 1600 mg/kg of phenibut. On presentation to an emergency clinic, the dog was neurologically inappropriate, tachycardic, hypertensive, and exhibiting a profoundly decreased respiratory rate. Because of progressive clinical signs, electrolyte abnormalities, increased hepatic enzyme activity and bilirubin concentrations, and the development of pigmenturia, referral to specialist care was sought. On presentation, the dog was intermittently somnolent and then maniacal. Sinus tachycardia persisted, and hyperthermia was documented. Hospitalization for supportive care was undertaken, and the dog was administered IV fluids, flumazenil, antiepileptics, and IV lipid emulsion therapy. The dog developed hypoglycemia and treated with dextrose supplementation. Progressive increases in liver enzyme activities as well as pronounced increase in creatine kinase activity, consistent with rhabdomyolysis, were noted. Over the course of 48 hours, the hypoglycemia resolved, and clinical signs significantly improved. Ultimately, the dog was discharged with improved clinical signs, with the owner reporting that 1 week after discharge, a full recovery had been made, and no residual clinical signs persisted.

NEW INFORMATION PROVIDED

To the authors' knowledge, there are no previous reports of phenibut intoxication in small animals. The growing availability and use of this drug by people in the past several years highlight the need for a greater understanding of its effects in companion animals.

Clinical Presentations and Treatment of Phenibut Toxicity and Withdrawal: A Systematic Literature Review

OBJECTIVES

This systematic review aimed to identify published articles that evaluated all phenibut toxicity and withdrawal cases to understand better their clinical presentations and treatments.

METHODS

A comprehensive literature search was conducted using Medline (Ovid), Embase (Ovid), and Cochrane Library databases to capture all published cases on the presentations and management of phenibut toxicity or withdrawal.

RESULTS

Sixty-two cases from 36 studies on presentation and management of phenibut toxicity or phenibut withdrawal were identified. Of all subjects, 80.7% were male. The average age was 30.9 years (SD, 13.2 years; range, 0-71 years). A total of 86.8% reported obtaining phenibut online, and 63.2% reported concomitant substance use with other addictive agents; benzodiazepines and alcohol were the most combined drugs. The average length of hospital stay was 5.0 days (n = 25; SD, 5.4 days; range, 1-25 days) for phenibut toxicity and 7.7 days (n = 20; SD, 7.8 days; range, 0-30 days) for phenibut withdrawals. The most common symptoms reported during phenibut toxicity were altered mental status, somnolence, psychosis, and movement disorders. Of the phenibut toxicity cases, 48.7% required intubation. Benzodiazepines and antipsychotics were most used to treat phenibut toxicity. For phenibut withdrawal cases, 95.7% reported daily use. The most common symptoms reported during phenibut withdrawals were anxiety, irritability or agitation, insomnia, and psychosis. Sixteen (69.6%) of phenibut withdrawal cases required multiple medications for treatment. Benzodiazepines, baclofen, atypical antipsychotics, gabapentanoids, and barbiturates were commonly used to treat phenibut withdrawals.

CONCLUSIONS

The seriousness of presentations, combined with the assortments of medications used for both syndromes, reflects the potential dangers of phenibut use and the need for systematized treatment protocols.

Management of Phenibut Use Disorder and Withdrawal in a Geriatric Patient

Phenibut is a misused substance which has shown an increase in use over the past decade. Marketed as a "dietary supplement," it is not approved in the United States for use and is not regulated by the Food and Drug Administration. The substance, however, is readily available for purchase through online markets. It has a similar drug profile as alcohol, gabapentin and benzodiazepines. Clinical effects of this drug include physiologic dependence, euphoria, anxiolysis, antispasticity, sedation, and possible nootropic properties. While there are emerging new cases of managing phenibut withdrawal, no cases currently feature phenibut addiction and withdrawal management in the geriatric population. Here we discuss such a case of phenibut addiction and withdrawal in a 68-year-old male who initially began misusing phenibut to alleviate anxiety and insomnia precipitated by worsening affective disorder, sedative, hypnotic, or anxiolytic use disorder, and alcohol use disorder.

An Unusual Presentation of an Uncommon Drug: A Case Report on Phenibut Overdose

Phenibut (β-phenyl-γ-aminobutyric acid), a nootropic, gamma-aminobutyric acid receptor agonist, commercially marketed for anxiolysis, is increasingly recognized for its recreational abuse potential. We present the case of a 30-year-old-male with a history of polysubstance abuse, anxiety, and depression, who presented to the Emergency Department by ambulance for altered mental status with severe agitation, requiring both sedation and mechanical ventilation. It was later discovered that he had consumed phenibut, which he purchased through the internet. Currently, no readily available confirmatory laboratory tests exist to aid in the diagnosis of acute phenibut intoxication. We highlight the clinical distinctions between features of acute phenibut intoxication and withdrawal.

A Case of Phenibut Directed Detoxification Leading to Toxicity During the COVID-19 Pandemic

BACKGROUND

Phenibut is a non-Food and Drug Administration-approved gamma-aminobutyric acid analog marketed in the United States as an anxiolytic, cognitive enhancer, and alcohol withdrawal treatment through online supplement vendors. In this case report, we describe a woman's self-directed detoxification with phenibut used to manage withdrawal symptoms from fentanyl and benzodiazepines in March 2020 during the height of the COVID-19 pandemic.

CASE

A 38-year-old woman with severe opioid, benzodiazepine, gabapentin, stimulant use disorders developed altered mental status after oral phenibut ingestion intended to help self-manage opioid and benzodiazepine withdrawal. She chose self-directed detoxification as she feared COVID-19 exposure in detoxification facilities. Her altered mental status drove her to jump out a third-story window causing multiple spinal fractures. After a long hospitalization, she self-directed her discharge home due to concerns about COVID-19. Her premature discharge disrupted opioid and benzodiazepine use disorder treatment plans.

CONCLUSION

This case highlights the risks of phenibut use for selfdirected detoxification. With COVID-19 related changes in the drug supply, people may be more likely to use online pharmaceuticals, therefore, substance use assessments should inquire about the online acquisition of new psychoactive drugs. Public health messaging regarding the risks of infectious disease transmission in addiction care settings is needed to guide addiction treatment choices among people who use substances.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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When an obscurity becomes trend: social-media descriptions of tianeptine use and associated atypical drug use

Background: Originally believed to be an atypical antidepressant acting at serotonin transporters, tianeptine is now known to also be an atypical agonist at mu-opioid receptors. Its nonmedical use may be increasing amidst the broader context of novel drug and supplement use.Objectives: To analyze social-media text from current, former, and prospective tianeptine users for better understanding of their conceptualizations of tianeptine, motives for and patterns of use, and reported benefits and harms.Methods: Reddit posts were obtained and thematically coded; additional quantitative analyses were conducted.Results: A total of 210 posts mentioning tianeptine were made between 2012 and 2020. Eighteen thematic categories were identified, 10 of which were consistent with expected themes. Two independent raters coded all text, generating 1,382 unique codes, of which 1,090 were concordant (78.9% interrater agreement). Tianeptine use was frequently associated with use of other drugs, particularly kratom, phenibut, and racetams. People conceptualized and variously used tianeptine as an opioid, antidepressant, and "nootropic" (cognitive enhancer). Between 2014 and 2020, mentions of positive effects decreased, while mentions of adverse effects and withdrawal increased. Motivations for use included substitution or withdrawal mitigation for other drugs (especially opioids) and for kratom itself; self-treatment for psychiatric symptoms; and improvement of quality of life, mood, or performance. Descriptions of tolerance, withdrawal, and addiction were evident. Intravenous use was rare and strongly discouraged, with detrimental effects described.Conclusion: Tianeptine is recognized as an opioid (though not only an opioid) in online communities. Posts describe benefits, acute risks, and patterns of co-use that warrant greater clinical attention.

Risk Associated with the Use of Selected Ingredients in Food Supplements

This review focuses on four new product categories of food supplements: pre-workout, fat burner/thermogenic, brain/cognitive booster, and hormone/testosterone booster. Many food supplements have been shown to be contaminated with unauthorized substances. In some cases, the ingredients in the new categories of dietary supplements were medicinal products or new synthetic compounds added without performing clinical trials. Some of the new ingredients in dietary supplements are plant materials that are registered in the pharmacopoeia as herbal medicines. In other cases, dietary supplements may contain plant materials that have no history of human use and are often used as materials to 'camouflage' stimulants. In the European Union, new ingredients of dietary supplements, according to European Food Safety Authority or unauthorized novel food. Furthermore, selected ingredients in dietary supplements may be prohibited in sports and are recognized as doping agents by World Anti-Doping Agency.

Psychomotor Agitation Non-responsive to Treatment: A Case Report of Phenibut Withdrawal Syndrome

Background and Objectives: Phenibut (4-amino-3-phenyl-butyric acid), acting as a GABA-B receptor agonist, has a beneficial effect on anxiety. Although its medical use is not approved in western countries, it can be easily obtained worldwide via the Internet, so it spread as a substance of abuse. In recent years, some case reports have, therefore, highlighted episodes of acute toxicity or withdrawal, but it is still a largely unknown phenomenon. Methods: In this case report, a 50-year-old woman was admitted to the emergency room with psychomotor agitation, psychotic symptoms, and insomnia, and was non-responsive to treatment. She was hospitalized at the psychiatry ward for 25 days and gave her consent for the publication of the present case report. Results: The suspicion of phenibut withdrawal allowed to establish the appropriate management, leading to the restitutio ad integrum of the psychopathological case. Conclusions: In the face of an incoercible psychomotor agitation case, the knowledge of the so-called novel psychoactive substances allows for more appropriate clinical management of intoxication and withdrawal syndromes. This is a scientifically significant report as it provides therapeutic and outcome data concerning a syndrome that is still quite unfamiliar.

The Psychonauts' World of Cognitive Enhancers

BACKGROUND

There is growing availability of novel psychoactive substances (NPS), including cognitive enhancers (CEs) which can be used in the treatment of certain mental health disorders. While treating cognitive deficit symptoms in neuropsychiatric or neurodegenerative disorders using CEs might have significant benefits for patients, the increasing recreational use of these substances by healthy individuals raises many clinical, medico-legal, and ethical issues. Moreover, it has become very challenging for clinicians to keep up-to-date with CEs currently available as comprehensive official lists do not exist.

METHODS

Using a web crawler (NPSfinder®), the present study aimed at assessing psychonaut fora/platforms to better understand the online situation regarding CEs. We compared NPSfinder® entries with those from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and from the United Nations Office on Drugs and Crime (UNODC) NPS databases up to spring 2019. Any substance that was identified by NPSfinder® was considered a CE if it was either described as having nootropic abilities by psychonauts or if it was listed among the known CEs by Froestl and colleagues.

RESULTS

A total of 142 unique CEs were identified by NPSfinder®. They were divided into 10 categories, including plants/herbs/products (29%), prescribed drugs (17%), image and performance enhancing drugs (IPEDs) (15%), psychostimulants (15%), miscellaneous (8%), Phenethylamines (6%), GABAergic drugs (5%), cannabimimetic (4%), tryptamines derivatives (0.5%), and piperazine derivatives (0.5%). A total of 105 chemically different substances were uniquely identified by NPSfinder®. Only one CE was uniquely identified by the EMCDDA; no CE was uniquely identified by the UNODC.

CONCLUSIONS

These results show that NPSfinder® is helpful as part of an Early Warning System, which could update clinicians with the growing numbers and types of nootropics in the increasingly difficult-to-follow internet world. Improving clinicians' knowledge of NPS could promote more effective prevention and harm reduction measures in clinical settings.

Safety and Tolerability of the Anxiolytic and Nootropic Drug Phenibut: A Systematic Review of Clinical Trials and Case Reports

Phenibut is a nootropic drug that exerts anxiolytic and antinociceptive effects by acting on the GABA_B receptor and the α₂-δ subunit of voltage-dependent calcium channels. An increased number of reports of dependence to and intoxication by phenibut purchased online on the one hand and the wide prescription of phenibut in Eastern Europe for more than half a century on the other hand have resulted in a number of controversies regarding its use. In this review, we have summarized currently available information from case reports of phenibut dependence and intoxication and safety data from clinical trials. We included 14 dependence and intoxication case reports (16 patients) and reviewed 11 phenibut clinical trials (583 patients). The clinical symptoms in the case reports included cardiovascular effects, insomnia, anxiety and agitation, hallucinations, and depressed level of consciousness. In addition, the doses used (0.5-100 g/day) were much higher than the recommended daily dose (0.25-2 g/day). An analysis of phenibut side effects described in the clinical trials showed adverse events in only 5.66% of patients, and the most reported side effect was somnolence (1.89%). There are discrepancies in the reported side effects of phenibut in clinical trials compared to those reported in cases of online-purchased phenibut dependence and intoxication. The current systematic review provides evidence that, at therapeutic doses, phenibut is safe and well tolerated with minor adverse effects, but questions regarding the quality of phenibut obtained online and the contribution of alcohol and other drug abuse to phenibut dependence and intoxication remain open.

Designer drugs: mechanism of action and adverse effects

Psychoactive substances with chemical structures or pharmacological profiles that are similar to traditional drugs of abuse continue to emerge on the recreational drug market. Internet vendors may at least temporarily sell these so-called designer drugs without adhering to legal statutes or facing legal consequences. Overall, the mechanism of action and adverse effects of designer drugs are similar to traditional drugs of abuse. Stimulants, such as amphetamines and cathinones, primarily interact with monoamine transporters and mostly induce sympathomimetic adverse effects. Agonism at μ-opioid receptors and γ-aminobutyric acid-A (GABA_A) or GABA_B receptors mediates the pharmacological effects of sedatives, which may induce cardiorespiratory depression. Dissociative designer drugs primarily act as N-methyl-d-aspartate receptor antagonists and pose similar health risks as the medically approved dissociative anesthetic ketamine. The cannabinoid type 1 (CB₁) receptor is thought to drive the psychoactive effects of synthetic cannabinoids, which are associated with a less desirable effect profile and more severe adverse effects compared with cannabis. Serotonergic 5-hydroxytryptamine-2A (5-HT_2A) receptors mediate alterations of perception and cognition that are induced by serotonergic psychedelics. Because of their novelty, designer drugs may remain undetected by routine drug screening, thus hampering evaluations of adverse effects. Intoxication reports suggest that several designer drugs are used concurrently, posing a high risk for severe adverse effects and even death.

The Availability of Modafinil and Methylphenidate Purchased from the Internet in the United Kingdom Without a Prescription

Background: There are reports of prescription stimulants being purchased online for use as cognitive enhancers or "smart drugs." Objectives: The aim of this study was to investigate availability of modafinil and methylphenidate from internet suppliers from the perspective of a typical United Kingdom (UK) based customer. Methods: Using European Monitoring Center for Drugs and Drug Addiction (EMCDDA) internet snapshot methodology, we undertook an English language internet snapshot survey in July-August 2018 to gather information on the availability and price of modafinil and methylphenidate from online retailers. Results: A total of 55 modafinil and 14 methylphenidate websites were identified from which the drug could be purchased without a prescription. Minimum purchase quantities ranged from 10 to 90 tablets for modafinil and 1-1,005 tablets for methylphenidate with no apparent upper limit to the number that could be purchased. The price per tablet varied from £0.38-5.31 for modafinil and £0.16-5.70 for methylphenidate. Free shipping was offered if more than a certain amount was spent on 46 (83.6%) modafinil and 7 (50.0%) methylphenidate websites and discounts were offered on 43 (78.2%) modafinil and 4 (28.6%) methylphenidate websites. Conclusions: Modafinil and methylphenidate are widely available to purchase via internet from the UK without a prescription. The pricing on websites encourages users to buy greater quantities to qualify for discounts and free shipping. The quantities available suggest these purchases may be used in greater amounts than would be legitimately prescribed, increasing the risk of misuse or diversion to other individuals.

Phenibut Addiction in a Patient with Substance Use Disorder

Phenibut, a γ-aminobutyric acid (GABA) analog, is a synthetic, nootropic GABA_B receptor agonist used to treat anxiety, insomnia, alcohol withdrawal, and other conditions. The drug is licensed and widely used in Russia however, phenibut can be purchased through online vendors in other countries. The current literature on the effects of phenibut intoxication and withdrawal in humans is limited. In this case report, a 23-year-old male with a history of heavy phenibut and alcohol use presented to the emergency department with suicidal thoughts, somatic complaints, and seeking help with detoxification. His history and physical revealed symptoms indicative of alcohol withdrawal, but the extended period of his symptoms suggested an additive effect of his phenibut use. This unique case report illustrates how concurrent and heavy use of phenibut with alcohol may contribute to an extended and exacerbated withdrawal syndrome.

Phenibut (β-Phenyl-γ-Aminobutyric Acid): an Easily Obtainable "Dietary Supplement" With Propensities for Physical Dependence and Addiction

PURPOSE OF REVIEW

Phenibut (β-phenyl-γ-aminobutyric acid) is a psychoactive GABA analogue currently being marketed online as an anxiolytic and nootropic dietary supplement. Its use is growing in popularity, but its pharmacological activity is well beyond that of a conventional nutritional supplement, and similar to that of a prescription strength sedative. This review will focus on the potential adversities of phenibut use and will discuss what treatment options may be beneficial to afflicted patients.

RECENT FINDINGS

Over the last several years, multiple case reports have highlighted phenibut's potential to produce the conditions of physical dependence, withdrawal, and addiction. In cases involving intoxication, patients have presented with a varying degree of mental status changes, from being minimally responsive to manifesting symptoms of an agitated delirium. Phenibut is a potent psychoactive substance with GABA_B agonist properties, which is emerging as a drug of misuse through growing internet sales. Its marketing as a "dietary supplement" is inaccurate and misleading, given its pharmacological profile and ability to induce the physiological changes associated with withdrawal and physical dependence.

Novel Drugs of Abuse

Novel drugs of abuse are synthetic illicit drugs, or analogues of known illicit drugs, that can be more potent. Novel drugs of abuse are often labeled as designer drugs, research chemicals, legal highs, or psychoactive substances. They are often sold as designated legal or nondrug products, such as incense, plant food, or bath salts, with labeling such as "Not for Human Consumption" or "For Use in Research Only." The prevalence of use of novel drugs of abuse is difficult to determine because specific drugs, compounds, and availability of these drugs are constantly evolving. Changes in chemical structures lead to heterogeneity in physiologic response and clinical symptoms, even within the same category of drug. Pediatricians and emergency medicine physicians should be knowledgeable about novel drugs of abuse and their resulting symptoms for prevention and identification of their use.

Phenibut (β-Phenyl-γ-aminobutyric Acid) Dependence and Management of Withdrawal: Emerging Nootropics of Abuse

This case report describes the development of withdrawal from phenibut, a gamma-aminobutyric acid-receptor type B agonist. Although phenibut is not an FDA-approved medication, it is available through online retailers as a nootropic supplement. There are reports of dependence in patients that misuse phenibut. We report a case in which a patient experienced withdrawal symptoms from phenibut and was successfully treated with a baclofen taper. This case report highlights the development of phenibut use disorder with coingestion of alcohol and potential management for phenibut withdrawal. We believe clinicians must be aware of how phenibut dependence may present and how to manage the withdrawal syndrome.

Responding to New Psychoactive Substances in the European Union: Early Warning, Risk Assessment, and Control Measures

New psychoactive substances (NPS) are drugs that are not controlled by the United Nations international drug control conventions of 1961 and 1971 but that may pose similar threats to public health. Many of them are traded as "legal" replacements to controlled drugs such as cannabis, heroin, benzodiazepines, cocaine, amphetamines, and 3,4-methylenedioxymethamphetamine (MDMA). Driven by globalization, there has been a large increase in the availability and, subsequently, harms caused by these substances over the last decade in Europe. The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) is monitoring more than 670 NPS that have appeared on Europe's drug market in the last 20 years, of which almost 90% have appeared in the last decade. While some recent policy responses have been successful in reducing availability and sales of these substances in some settings - such as "legal highs" and "research chemicals" sold openly in the high street and online - and there are signs that growth in the market is slowing, new challenges have emerged. This includes monitoring a growing number of highly potent substances - including 179 synthetic cannabinoid receptor agonists and 28 fentanils - that can pose a high risk of life-threatening poisoning to users and can cause explosive outbreaks. This chapter briefly traces the origins of NPS, provides an overview of the situation in Europe, and discusses the work of the EMCDDA as part of a legal framework of early warning, risk assessment, and control measures that allows the European Union to rapidly detect, assess, and respond to public health and social threats caused by these substances.

Case Report of Physiologic Phenibut Dependence Treated With a Phenobarbital Taper in a Patient Being Treated With Buprenorphine

: This case report describes the development of dependence to phenibut, a gamma-aminobutyric acid-receptor type B agonist, in a patient concurrently being treated with buprenorphine. The patient experienced withdrawal symptoms which were successfully treated with a phenobarbital taper based on a protocol to treat sedative use disorder. This case report provided an example of the development of a phenibut use disorder and also brought up a public health question of whether phenibut should therefore be officially classified and monitored.

New psychoactive substances: an overview on recent publications on their toxicodynamics and toxicokinetics

This review article covers English-written and PubMed-listed review articles and original studies published between January 2015 and April 2016 dealing with the toxicodynamics and toxicokinetics of new psychoactive substances. Compounds covered include stimulants and entactogens, synthetic cannabinoids, tryptamines, NBOMes, phencyclidine-like drugs, benzodiazepines, and opioids. First, an overview and discussion is provided on timely review articles followed by an overview and discussion on recent original studies. Both sections are then concluded by an opinion on these latest developments. This review shows that the NPS market is still highly dynamic and that the data published on their toxicodynamics and toxicokinetics can hardly keep pace with the appearance of new entities. However, data available are very helpful to understand and predict how NPS may behave in severe intoxication. The currently best-documented parameter is the in vitro metabolism of NPS, a prerequisite to allow detection of NPS in biological matrices in cases of acute intoxications or chronic consumption. However, additional data such as their chronic toxicity are still lacking.