Phenibut

{{Short description|CNS depressant medication}} {{Use dmy dates|date=October 2020}} {{Infobox drug | Verifiedfields = verified | Watchedfields = verified | verifiedrevid = 464373947 | IUPAC_name = 4-Amino-3-phenylbutanoic acid | image = Phenibut skeletal formula.svg | image_class = skin-invert-image | width = 200px | image2 = Phenibut ball-and-stick model.png | image_class2 = bg-transparent | width2 = 200px

| tradename = Anvifen, Fenibut, Noofen, others<ref name="DrobizhevFedotova2016">{{cite journal | vauthors = Drobizhev MY, Fedotova AV, Kikta SV, Antohin EY | year = 2016 | title = Феномен аминофенилмасляной кислоты | trans-title = Phenomenon of aminophenylbutyric acid | url = https://www.rmj.ru/articles/nevrologiya/Fenomen_aminofenilmaslyanoy_kisloty/ | language = Russian | journal = Russian Medical Journal | volume = 2017 | issue = 24 | pages = 1657–1663 | issn = 1382-4368 | access-date = 16 September 2017 | archive-date = 16 September 2017 | archive-url = https://web.archive.org/web/20170916053610/https://www.rmj.ru/articles/nevrologiya/Fenomen_aminofenilmaslyanoy_kisloty/ | url-status = live }}</ref> | pregnancy_AU =  | pregnancy_US =  | dependency_liability = | addiction_liability = | legal_AU = S9 | legal_CA = Unscheduled  | legal_DE = NPSG | legal_US = Unapproved drug; use in dietary supplements, food, or medicine is unlawful<ref>{{Cite journal |last=Nutrition |first=Center for Food Safety and Applied |date=2023-03-06 |title=Phenibut in Dietary Supplements |url=https://www.fda.gov/food/dietary-supplement-ingredient-directory/phenibut-dietary-supplements |journal=FDA |language=en |access-date=23 May 2023 |archive-date=23 May 2023 |archive-url=https://web.archive.org/web/20230523031247/https://www.fda.gov/food/dietary-supplement-ingredient-directory/phenibut-dietary-supplements |url-status=dead }}</ref> | legal_UN = Unscheduled | legal_status = RU: Rx-only | routes_of_administration = Common: Oral<ref name="pmid26693960" /> Uncommon: Rectal<ref name="pmid26693960" /> | class = GABAB receptor agonist; Gabapentinoid

| bioavailability = ≥63% (250 mg)<ref name="pmid11830761" /> | protein_bound = | metabolism = Liver (minimal)<ref name="Phenibut-Label">{{citation | author = Ozon Pharm | title = Fenibut | access-date = 15 September 2017 | url = http://www.ozonpharm.ru/upload/iblock/608/nmntxzabdzjhlu%20-%20fbdoqpbtdj.ofzsxp%20tkbgeygfzj.pdf | archive-url = https://web.archive.org/web/20170916094855/http://www.ozonpharm.ru/upload/iblock/608/nmntxzabdzjhlu%20-%20fbdoqpbtdj.ofzsxp%20tkbgeygfzj.pdf | archive-date = 16 September 2017 | url-status = dead }}</ref><ref name="pmid11830761" /> | metabolites = Inactive<ref name="Phenibut-Label" /> | elimination_half-life = 5.3 hours (250 mg)<ref name="pmid11830761" /> | onset = Oral: 2–4 hours<ref name="pmid26693960" /> Rectal: 20–30 minutes<ref name="pmid26693960" /> | duration_of_action = 15–24 hours (1–3 g)<ref name="pmid26693960" /> | excretion = Urine: 63% (unchanged)<ref name="pmid11830761" />

| CAS_number_Ref = {{cascite|correct|CAS}} | CAS_number = 1078-21-3 | CAS_supplemental = 3060-41-1 (hydrochloride) | UNII_Ref = {{fdacite|changed|FDA}} | UNII = T2M58D6LA8 | ATC_prefix = N06 | ATC_suffix = BX22 | PubChem = 14113 | DrugBank_Ref = {{drugbankcite|correct|drugbank}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 13491 | ChEMBL_Ref = {{ebicite|correct|EBI}} | ChEMBL = 315818 | KEGG_Ref = {{keggcite|correct|kegg}} | KEGG = D10509 | synonyms = Aminophenylbutyric acid; Fenibut; Fenigam; Phenigam; Phenybut; Phenygam; Phenylgamma; Phenigama; PHG; PhGABA; β-Phenyl-γ-aminobutyric acid; β-Phenyl-GABA<ref name="Elks2014">{{cite book| vauthors = Elks J |title=The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies|url=https://books.google.com/books?id=0vXTBwAAQBAJ&pg=PA69|date=14 November 2014|publisher=Springer|isbn=978-1-4757-2085-3|pages=69–}}</ref>

| C = 10 | H = 13 | N = 1 | O = 2 | SMILES = O=C(O)CC(c1ccccc1)CN | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C10H13NO2/c11-7-9(6-10(12)13)8-4-2-1-3-5-8/h1-5,9H,6-7,11H2,(H,12,13) | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = DAFOCGYVTAOKAJ-UHFFFAOYSA-N

| melting_point = 253 }}

'''Phenibut''', sold under the brand name '''Anvifen''' among others,<ref name="DrobizhevFedotova2016" /> is a central nervous system (CNS) depressant with anxiolytic effects, and is used to treat anxiety, insomnia, and for a variety of other indications.<ref name="pmid11830761">{{cite journal | vauthors = Lapin I | title = Phenibut (beta-phenyl-GABA): a tranquilizer and nootropic drug | journal = CNS Drug Reviews | volume = 7 | issue = 4 | pages = 471–81 | year = 2001 | pmid = 11830761 | pmc = 6494145 | doi = 10.1111/j.1527-3458.2001.tb00211.x }}</ref> It is usually taken orally (swallowed by mouth), but may be given intravenously.<ref name="Phenibut-Label" /><ref name="pmid11830761" />

Side effects of phenibut can include sedation, sleepiness, nausea, irritability, agitation, dizziness, euphoria, and sometimes headache, among others.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> Overdose of phenibut can produce marked central nervous system depression including unconsciousness.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> The medication is structurally related to the neurotransmitter γ-aminobutyric acid (GABA), and hence is a GABA analogue.<ref name="pmid11830761" /> Phenibut is thought to act as a GABAB receptor agonist, similarly to baclofen and γ-hydroxybutyrate (GHB).<ref name="pmid11830761" /> However, at low concentrations, phenibut mildly increases the concentration of dopamine in the brain, providing stimulatory effects in addition to the anxiolysis.<ref>{{cite journal | vauthors = Lapin I | title = Phenibut (beta-phenyl-GABA): a tranquilizer and nootropic drug | journal = CNS Drug Reviews | volume = 7 | issue = 4 | pages = 471–81 | date = 2006-06-07 | pmid = 11830761 | pmc = 6494145 | doi = 10.1111/j.1527-3458.2001.tb00211.x }}</ref>

Phenibut was developed in the Soviet Union and was introduced for medical use in the 1960s.<ref name="pmid11830761" /> Today, it is marketed for medical use in Russia, Ukraine, Belarus, Kazakhstan, and Latvia.<ref name="pmid11830761" /> The medication is not approved for clinical use in the United States and most of Europe, but it is sold on the Internet as a supplement and purported nootropic.<ref name="pmid26693960" /><ref name="ClinicalTox">{{cite journal | vauthors = Cohen PA, Ellison RR, Travis JC, Gaufberg SV, Gerona R | title = Quantity of phenibut in dietary supplements before and after FDA warnings | journal = Clinical Toxicology | volume = 60 | issue = 4 | pages = 486–488 | date = April 2022 | pmid = 34550038 | doi = 10.1080/15563650.2021.1973020 | s2cid = 237594860 }}</ref> Phenibut has been used recreationally and can produce euphoria as well as addiction, dependence, and withdrawal.<ref name="pmid26693960" /> It is a controlled substance in Australia, and it has been suggested that its legal status should be reconsidered in Europe as well.<ref name="pmid26693960" /> In Germany, phenibut is not approved as a drug and, as a food supplement, is controlled under the German New Psychoactive Substances Act.<ref name="Anlage NpSG - Einzelnorm">{{Cite web |title=Anlage NpSG - Einzelnorm |url=https://www.gesetze-im-internet.de/npsg/anlage.html |access-date=2024-06-07 |website=www.gesetze-im-internet.de}}</ref>

In a 2023 assessment, the U.S. Food and Drug Administration (FDA) determined that phenibut does not meet the definition of a dietary ingredient, thereby making phenibut supplement products misbranded and illegal for marketing.<ref name="fda-23">{{cite web |title=Phenibut in Dietary Supplements |url=https://www.fda.gov/food/information-select-dietary-supplement-ingredients-and-other-substances/phenibut-dietary-supplements |publisher=US Food and Drug Administration |access-date=14 September 2024 |date=12 July 2023}}</ref> FDA warning letters had been issued to supplement manufacturers marketing phenibut products as adulterated.<ref name="fda-19">{{cite web |title=FDA Acts on Dietary Supplements Containing DMHA and Phenibut |url=https://www.fda.gov/food/cfsan-constituent-updates/fda-acts-dietary-supplements-containing-dmha-and-phenibut |publisher=US Food and Drug Administration |access-date=14 September 2024 |date=29 April 2019 |archive-date=14 June 2022 |archive-url=https://web.archive.org/web/20220614224615/https://www.fda.gov/food/cfsan-constituent-updates/fda-acts-dietary-supplements-containing-dmha-and-phenibut |url-status=dead }}</ref>

==Medical uses== Phenibut is used in Russia, Ukraine, Belarus and Latvia as a pharmaceutical drug to treat anxiety and to improve sleep (e.g., in the treatment of insomnia).<ref name="pmid11830761" /><ref name="Phenibut-Label" /> It is also used for various other indications, including the treatment of asthenia, depression, alcoholism, alcohol withdrawal syndrome, post-traumatic stress disorder, stuttering, tics, vestibular disorders, Ménière's disease, dizziness, for the prevention of motion sickness, and for the prevention of anxiety before or after surgical procedures or painful diagnostic tests.<ref name="Phenibut-Label" /><ref name="pmid11830761" />

===Available forms=== Phenibut is available as a medication in the form of 250 mg or 500 mg tablets for oral administration and as a solution at a concentration of 10 mg/mL for infusion.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut">{{cite web | author = Регистр лекарственных средств России ([Russian Medicines Register]) | title = Фенибут (Phenybutum) | trans-title = Fenibut (Phenybutum) | language = Russian | access-date = 15 September 2017 | url = https://www.rlsnet.ru/tn_index_id_5320.htm | archive-date = 3 March 2009 | archive-url = https://web.archive.org/web/20090303232933/https://www.rlsnet.ru/tn_index_id_5320.htm | url-status = live }}</ref><ref name="SivchikGrygoryan" /> In the US, dietary supplements labeled as containing phenibut have been found to contain zero to greater than 1,100 mg of phenibut per serving.<ref name="ClinicalTox" />

==Contraindications== Contraindications of phenibut include:<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> * Intolerance to phenibut * Pregnancy and breastfeeding * Children who are younger than two years of age * Liver insufficiency or failure * Ulcerative lesions of the gastrointestinal tract

Phenibut should not be combined with alcohol.<ref name="RLS-Phenibut" />

==Side effects== Phenibut is generally well-tolerated.<ref name="pmid11830761" /><ref name="RLS-Phenibut" /> Possible side effects may include sedation, somnolence, nausea, irritability, agitation, anxiety, dizziness, headache, and allergic reactions such as skin rash and itching.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> At high doses, motor incoordination, loss of balance, and hangovers may occur.<ref name="pmid26693960" /> Due to its CNS depressant effects, people taking phenibut should refrain from potentially dangerous activities such as operating heavy machinery.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> With prolonged use of phenibut, particularly at high doses, the liver and blood should be monitored, due to risk of fatty liver disease and eosinophilia.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" />

=== Dependence and withdrawal === Tolerance to phenibut easily develops with repeated use, leading to dependence.<ref name="pmid11830761" />{{Update inline|date=August 2023}} Withdrawal symptoms may occur upon discontinuation, and, in recreational users taking high doses, have been reported to include severe rebound anxiety, insomnia, aggression, irritability, agitation, visual and auditory hallucinations, and acute psychosis.<ref name="pmid26693960" /> Baclofen has successfully been used for treatment of phenibut dependence.<ref>{{cite journal |vauthors=Samokhvalov AV, Paton-Gay CL, Balchand K, Rehm J |date=February 2013 |title=Phenibut dependence |journal=BMJ Case Reports |volume=2013 |pages=bcr2012008381 |doi=10.1136/bcr-2012-008381 |pmc=3604470 |pmid=23391959}}</ref>

==Overdose== In overdose, phenibut can cause severe drowsiness, nausea, vomiting, eosinophilia, lowered blood pressure, renal impairment, and, above 7 grams, fatty liver degeneration.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> There are no specific antidotes for phenibut overdose.<ref name="RLS-Phenibut" /> Lethargy, somnolence, agitation, delirium, tonic–clonic seizures, reduced consciousness or unconsciousness, and unresponsiveness have been reported in recreational users who have overdosed.<ref name="pmid26693960" /> Management of phenibut overdose includes activated charcoal, gastric lavage, induction of vomiting, and symptom-based treatment.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" /> There have been three associated deaths which found Phenibut in the users system but only one of these cases solely included Phenibut.<ref>{{cite journal | vauthors = Graves JM, Dilley J, Kubsad S, Liebelt E | title = Notes from the Field: Phenibut Exposures Reported to Poison Centers - United States, 2009–2019 | language = en-us | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 69 | issue = 35 | pages = 1227–1228 | date = September 2020 | pmid = 32881852 | pmc = 7470459 | doi = 10.15585/mmwr.mm6935a5 | doi-access = free }}</ref>

== Interactions ==

Phenibut may mutually potentiate and extend the duration of the effects of other CNS depressants, including anxiolytics, antipsychotics, sedatives, opioids, anticonvulsants, and alcohol.<ref name="Phenibut-Label" /><ref name="RLS-Phenibut" />

==Pharmacology== {{See also|Gabapentinoid#Pharmacology}}

===Pharmacodynamics=== {| class="wikitable floatright" |- |+ GABA and analogues at biological targets<ref name="pmid6297646">{{cite journal | vauthors = Bowery NG, Hill DR, Hudson AL | title = Characteristics of GABAB receptor binding sites on rat whole brain synaptic membranes | journal = British Journal of Pharmacology | volume = 78 | issue = 1 | pages = 191–206 | date = January 1983 | pmid = 6297646 | pmc = 2044790 | doi = 10.1111/j.1476-5381.1983.tb09380.x }}</ref> |- ! Compound !! GABAB !! GABAA |- | {{abbrlink|GABA|γ-Aminobutyric acid}} || 0.08 || 0.12 |- | {{abbrlink|GHB|γ-Hydroxybutyric acid}} || >100 || >100 |- | {{abbrlink|GABOB|γ-Amino-β-hydroxybutyric acid}} || 1.10 || 1.38 |- | Phenibut || 9.6 || >100 |- | 4-F-phenibut || 1.70 || >100 |- | Baclofen || 0.13 || >100 |- |   (''R'')-Baclofen || 0.13 || >100 |- |   (''S'')-Baclofen || 74.0 || >100 |- class="sortbottom" | colspan="3" | Values are IC50 (μM) in rat brain. |}

Phenibut acts as a full agonist of the GABAB receptor, similarly to baclofen.<ref name="AcademicPress2010">{{cite book|title=GABAb Receptor Pharmacology: A Tribute to Norman Bowery: A Tribute to Norman Bowery|url=https://books.google.com/books?id=_iMDQOA2UIsC&pg=PA25|date=21 September 2010|publisher=Academic Press|isbn=978-0-12-378648-7|pages=25–}}</ref><ref name="pmid18275958">{{cite journal | vauthors = Dambrova M, Zvejniece L, Liepinsh E, Cirule H, Zharkova O, Veinberg G, Kalvinsh I | title = Comparative pharmacological activity of optical isomers of phenibut | journal = European Journal of Pharmacology | volume = 583 | issue = 1 | pages = 128–134 | date = March 2008 | pmid = 18275958 | doi = 10.1016/j.ejphar.2008.01.015 }}</ref> It has between 30- and 68-fold lower affinity for the GABAB receptor than baclofen, and, in accordance, is used at far higher doses in comparison.<ref name="AcademicPress2010" /> (''R'')-Phenibut has more than 100-fold higher affinity for the GABAB receptor than does (''S'')-phenibut; hence, (''R'')-phenibut is the active enantiomer at the GABAB receptor.<ref name="AllanBates1990">{{cite journal | vauthors = Allan RD, Bates MC, Drew CA, Duke RK, Hambley TW, Johnston GA, Mewett KN, Spence I | display-authors= 6 |title=A new synthesis resolution and in vitro activities of (R)- and (S)-β-Phenyl-Gaba|journal=Tetrahedron|volume=46|issue=7|year=1990|pages=2511–2524|issn=0040-4020|doi=10.1016/S0040-4020(01)82032-9}}</ref>

{| class="wikitable floatright" |- |+ Phenibut and analogues at biological targets<ref name="pmid26234470">{{cite journal | vauthors = Zvejniece L, Vavers E, Svalbe B, Veinberg G, Rizhanova K, Liepins V, Kalvinsh I, Dambrova M | display-authors = 6 | title = R-phenibut binds to the α2-δ subunit of voltage-dependent calcium channels and exerts gabapentin-like anti-nociceptive effects | journal = Pharmacology, Biochemistry, and Behavior | volume = 137 | pages = 23–9 | date = October 2015 | pmid = 26234470 | doi = 10.1016/j.pbb.2015.07.014 | s2cid = 42606053 }}</ref> |- ! Compound !! {{abbr|α2δ|α2δ subunit-containing voltage-dependent calcium channels}} !! GABAB |- | Phenibut || {{abbr|ND|No data}} || 177 |- |   (''R'')-Phenibut || 23 || 92 |- |   (''S'')-Phenibut || 39 || >1,000 |- | Baclofen || 156 || 6 |- | Gabapentin || 0.05 || >1,000 |- class="sortbottom" | colspan="3" | Values are Ki (μM) in rat brain. |}

Phenibut also binds to and blocks α2δ subunit-containing VDCCs, similarly to gabapentin and pregabalin, and hence is a gabapentinoid.<ref name="pmid26234470" /><ref name="pmid26621244">{{cite journal | vauthors = Vavers E, Zvejniece L, Svalbe B, Volska K, Makarova E, Liepinsh E, Rizhanova K, Liepins V, Dambrova M | display-authors = 6 | title = The neuroprotective effects of R-phenibut after focal cerebral ischemia | journal = Pharmacological Research | volume = 113 | issue = Pt B | pages = 796–801 | date = November 2016 | pmid = 26621244 | doi = 10.1016/j.phrs.2015.11.013 }}</ref> Both (''R'')-phenibut and (''S'')-phenibut display this action with similar affinity (Ki = 23 and 39 μM, respectively).<ref name="pmid26234470" />

It is often claimed on websites about nootropics and elsewhere on the internet that phenibut increases dopamine. Three papers published in Russian by Soviet scientists in 1979, 1986, and 1990 report that phenibut increases dopamine in the striatum of rats and in the mouse brain.<ref name="dopaminw">{{cite journal |last1=Lapin |first1=Izyaslav |title=Phenibut (β-Phenyl-GABA): A Tranquilizer and Nootropic Drug |journal=CNS Drug Reviews |date=December 2001 |volume=7 |issue=4 |pages=471–481 |doi=10.1111/j.1527-3458.2001.tb00211.x|pmid=11830761 |pmc=6494145 }}</ref> The mechanism underlying this putative effect is unclear.<ref name="dopaminw"/> Structurally, phenibut can also be considered a derivative of phenethylamine, and some research suggests that phenibut antagonizes the action of phenethylamine.<ref name="dopaminw"/>

===Pharmacokinetics=== Little information thus far has been published on the clinical pharmacokinetics of phenibut.<ref name="pmid11830761" /> The drug is reported to be well-absorbed.<ref name="Phenibut-Label" /> It distributes widely throughout the body and across the blood–brain barrier.<ref name="Phenibut-Label" /> Approximately 0.1% of an administered dose of phenibut reportedly penetrates into the brain, with this said to occur to a much greater extent in young people and the elderly.<ref name="Phenibut-Label" /> Following a single 250 mg dose in healthy volunteers, its elimination half-life was approximately 5.3 hours and the drug was largely (63%) excreted in the urine unchanged.<ref name="pmid11830761" />

Some limited information has been described on the pharmacokinetics of phenibut in recreational users taking much higher doses (e.g., 1–3 grams) than typical clinical doses.<ref name="pmid26693960">{{cite journal | vauthors = Owen DR, Wood DM, Archer JR, Dargan PI | title = Phenibut (4-amino-3-phenyl-butyric acid): Availability, prevalence of use, desired effects and acute toxicity | journal = Drug and Alcohol Review | volume = 35 | issue = 5 | pages = 591–6 | date = September 2016 | pmid = 26693960 | doi = 10.1111/dar.12356 | hdl-access = free | hdl = 10044/1/30073 }}</ref><ref name="pmid25655145">{{cite journal | vauthors = Schifano F, Orsolini L, Duccio Papanti G, Corkery JM | title = Novel psychoactive substances of interest for psychiatry | journal = World Psychiatry | volume = 14 | issue = 1 | pages = 15–26 | date = February 2015 | pmid = 25655145 | pmc = 4329884 | doi = 10.1002/wps.20174 }}</ref> In these individuals, the onset of action of phenibut has been reported to be 2 to 4 hours orally and 20 to 30 minutes rectally, the peak effects are described as occurring 4 to 6 hours following oral ingestion, and the total duration for the oral route has been reported to be 15 to 24 hours (or about 3 to 5 terminal half-lives).<ref name="pmid26693960" />

==Chemistry== Phenibut is a synthetic aromatic amino acid. It is a chiral molecule and thus has two potential configurations, as (''R'')- and (''S'')-enantiomers.<ref name="pmid18275958" />

===Structure and analogues=== class=skin-invert-image|thumb|right|350px|Chemical structures of phenibut and analogues.

Phenibut is a derivative of the inhibitory neurotransmitter GABA.<ref name="pmid11830761" /> Hence, it is a GABA analogue.<ref name="pmid11830761" /> Phenibut is specifically the analogue of GABA with a phenyl ring substituted in at the β-position.<ref name="pmid11830761" /> As such, its chemical name is β-phenyl-γ-aminobutyric acid, which can be abbreviated as β-phenyl-GABA.<ref name="pmid11830761" /> The presence of the phenyl ring allows phenibut to cross the blood–brain barrier significantly, unlike GABA.<ref name="pmid11830761" /> Phenibut also contains the trace amine β-phenethylamine in its structure.<ref name="pmid11830761" />

Phenibut is closely related to a variety of other GABA analogues including baclofen (β-(4-chlorophenyl)-GABA), 4-fluorophenibut (β-(4-fluorophenyl)-GABA), tolibut (β-(4-methylphenyl)-GABA), pregabalin ((''S'')-β-isobutyl-GABA), gabapentin (1-(aminomethyl)cyclohexane acetic acid), and GABOB (β-hydroxy-GABA).<ref name="pmid11830761" /><ref name="pmid26234470" /> It has almost the same chemical structure as baclofen, differing from it only in having a hydrogen atom instead of a chlorine atom at the ''para'' position of the phenyl ring.<ref name="pmid11830761" /> Phenibut is also close in structure to pregabalin, which has an isobutyl group at the β position instead of phenibut's phenyl ring.<ref name="pmid26234470" />

A glutamate-derivative analogue of phenibut is glufimet (dimethyl 3-phenylglutamate hydrochloride).<ref name="pmid28726197">{{cite journal | vauthors = Perfilova VN, Popova TA, Prokofiev II, Mokrousov IS, Ostrovskii OV, Tyurenkov IN | title = Effect of Phenibut and Glufimet, a Novel Glutamic Acid Derivative, on Respiration of Heart and Brain Mitochondria from Animals Exposed to Stress against the Background of Inducible NO-Synthase Blockade | journal = Bulletin of Experimental Biology and Medicine | volume = 163 | issue = 2 | pages = 226–229 | date = June 2017 | pmid = 28726197 | doi = 10.1007/s10517-017-3772-4 | s2cid = 4907409 }}</ref>

===Synthesis=== A chemical synthesis of phenibut has been published.<ref name="SivchikGrygoryan">{{citation | vauthors = Sivchik VV, Grygoryan HO, Survilo VL, Trukhachova TV | title = Синтез γ-амино-β-фенилмасляной кислоты (фенибута) | trans-title = Synthesis of β-phenyl-γ-aminobutyric acid (phenibut) | language = Russian | year = 2012 | url = http://elib.bsu.by/bitstream/123456789/15950/1/C%D0%91%D0%9E%D0%A0%D0%9D%D0%98%D0%9A%202012.pdf#page=448 | access-date = 16 September 2017 | archive-date = 16 September 2017 | archive-url = https://web.archive.org/web/20170916095410/http://elib.bsu.by/bitstream/123456789/15950/1/C%D0%91%D0%9E%D0%A0%D0%9D%D0%98%D0%9A%202012.pdf#page=448 | url-status = live }}</ref>

==History== Phenibut was synthesized at the A. I. Herzen Leningrad Pedagogical Institute (USSR) by Professor Vsevolod Perekalin's team and tested at the Institute of Experimental Medicine, USSR Academy of Medical Sciences.<ref name="pmid11830761" /> It was introduced into clinical use in Russia in the 1960s.<ref name="pmid11830761" />

==Society and culture== [[File:Phenibut from Russia.png|thumb|right|225px|Olainfarm's pharmaceutical phenibut sold in Russia.]]

===Other names=== Alternate spellings include ''fenibut'' and ''phenybut''.<ref name="Elks2014" /> It is also sometimes referred to as ''aminophenylbutyric acid''.<ref name="DrobizhevFedotova2016" /> The word ''phenibut'' is a contraction of the chemical name of the drug, ''β-'''pheny'''l-γ-amino'''but'''yric acid''.<ref name="pmid11830761" /> In early publications, phenibut was referred to as ''fenigam'' and ''phenigama''.<ref name="pmid11830761" /><ref name="KhauninaLapin1976">{{cite journal| vauthors = Khaunina RA, Lapin IP |title=Fenibut, a new tranquilizer |journal=Pharmaceutical Chemistry Journal |volume=10 |issue=12 |year=1976 |pages=1703–1705 |issn=0091-150X |doi=10.1007/BF00760021 |s2cid=29071385}}</ref> The drug has not been assigned an {{abbrlink|INN|International Nonproprietary Name}}.<ref name="Elks2014" /><ref name="Phenibut-Label" />

===Brand names=== Phenibut is marketed in Russia, Ukraine, Belarus, and Latvia under the brand names Anvifen, Fenibut, Bifren, and Noofen (Russian: Анвифен, Фенибут, Бифрен and Ноофен, respectively).<ref name="DrobizhevFedotova2016" />

===Availability=== Phenibut is approved in Russia, Ukraine, Belarus, Georgia and Latvia for medical use.<ref name="pmid26693960" /> It is not approved or available as a medication in other countries in the European Union, the United States, or Australia.<ref name="pmid26693960" /> In countries where phenibut is not a licensed pharmaceutical drug, it is sold online without a prescription as a "nutritional supplement".<ref name="pmid26693960" /><ref name="ClinicalTox" /> It is often used as a form of self-medication for social anxiety.<ref name="pmid26693960" />

===Recreational use=== Phenibut is used recreationally due to its ability to produce euphoria, anxiolysis, and increased sociability,<ref name="pmid26693960" /> as well as remaining undetected in routine urinalysis. Because of its delayed onset of effects, first-time users often mistakenly take an additional dose of phenibut in the belief that the initial dose did not work.<ref name="pmid26693960" /> Recreational users usually take the drug orally; there are a few case reports of rectal administration and one report of insufflation, which was described as "very painful" and causing swollen nostrils.<ref name="pmid26693960" />

===Legal status=== As of 2021, phenibut is a controlled substance in Australia,<ref name="pmid26693960"/> France,<ref>Par [https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000032106035/] {{Webarchive|url=https://web.archive.org/web/20210508163545/https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000032106035/|date=8 May 2021}} La liste des substances psychotropes</ref> Hungary,<ref>{{Cite web|url=http://kozlonyok.hu/nkonline/MKPDF/hiteles/MK18170.pdf|title=39/2018. (XI. 8.) EMMI rendelet Az új pszichoaktív anyaggá minősített anyagokról vagy vegyületcsoportokról szóló 55/2014. (XII. 30.) EMMI rendelet módosításáról|access-date=14 November 2018|archive-date=14 November 2018|archive-url=https://web.archive.org/web/20181114141557/http://kozlonyok.hu/nkonline/MKPDF/hiteles/MK18170.pdf|url-status=live}}</ref> Italy,<ref name="Gazzetta Ufficiale 11/08/20">{{cite web | url= https://www.gazzettaufficiale.it/eli/id/2020/08/21/20A04540/SG | title= Gazzetta Ufficiale 11/08/20 | publisher= Lorenzo Arbolino | date= 11 August 2020 | access-date= 27 August 2020 | archive-date= 2 May 2024 | archive-url= https://web.archive.org/web/20240502165522/https://www.gazzettaufficiale.it/eli/id/2020/08/21/20A04540/SG | url-status= live }}</ref> Lithuania,<ref>{{Cite web|url=http://ntakd.lrv.lt/lt/naujienos/rinkos-ribojimo-priemones-fenibutui|title=RINKOS RIBOJIMO PRIEMONĖS FENIBUTUI!|website=ntakd.lrv.lt|language=lt|access-date=2020-01-27|archive-date=6 October 2021|archive-url=https://web.archive.org/web/20211006065759/https://ntakd.lrv.lt/lt/naujienos/rinkos-ribojimo-priemones-fenibutui|url-status=dead}}</ref><ref name=":0">{{Cite web|url=https://e-seimas.lrs.lt/portal/legalAct/lt/TAD/9aff1ef11ce911eaadfcfdb735b57421?jfwid=-bgd9aafbv|title=V-1431 Dėl Lietuvos Respublikos sveikatos apsaugos ministro 2000 m. sausio 6 d. įsakymo Nr. 5 "Dėl Narko...|website=e-seimas.lrs.lt|language=lt|access-date=2020-01-27|archive-date=27 January 2020|archive-url=https://web.archive.org/web/20200127002637/https://e-seimas.lrs.lt/portal/legalAct/lt/TAD/9aff1ef11ce911eaadfcfdb735b57421%3Fjfwid%3D-bgd9aafbv|url-status=live}}</ref> and Germany<ref name="Anlage NpSG - Einzelnorm"/> where, nevertheless, it is readily obtained online.<ref>{{Cite journal |vauthors=Bonnet U, Scherbaum N, Schaper A, Soyka M|title=Phenibut — an Illegal Food Supplement With Psychotropic Effects and Health Risks|date=5 April 2024 |doi= 10.3238/arztebl.m2024.0003|volume=121|pages=222–7|url=https://www.aerzteblatt.de/int/archive/article?id=238384 |journal=Deutsches Ärzteblatt International|issue=7 |pmid=38377332 |language=en|pmc=11539871}}</ref>

In 2015, it was suggested that the legal status of phenibut in Europe should be reconsidered due to its recreational potential.<ref name="pmid26693960" /> In February 2018, the Australian Therapeutic Goods Administration declared it a prohibited (schedule 9) substance, citing health concerns due to withdrawal and overdose.<ref>{{cite web|publisher=Australian Government Department of Health.|work=Administration Therapeutic Goods Administration|title=3.3 Phenibut|url=https://www.tga.gov.au/book-page/33-phenibut|access-date=6 November 2017|language=en|date=31 October 2017|archive-date=27 March 2020|archive-url=https://web.archive.org/web/20200327065227/https://www.tga.gov.au/book-page/33-phenibut|url-status=live}}</ref><ref>{{cite news | url= http://www.abc.net.au/news/2018-02-22/detectives-probe-if-drug-behind-school-overdose-bought-online/9471958 | title= Mass school overdose investigation focuses on banned Russian drug | newspaper= ABC News | publisher= Australian Broadcasting Corporation | date= 22 February 2018 | access-date= 22 February 2018 | archive-date= 22 February 2018 | archive-url= https://web.archive.org/web/20180222023735/http://www.abc.net.au/news/2018-02-22/detectives-probe-if-drug-behind-school-overdose-bought-online/9471958 | url-status= live }}</ref>

As of 14 November 2018, Hungary added phenibut and 10 other items to its New Psychoactive Substances ban list,<ref>{{cite web | url= https://net.jogtar.hu/jogszabaly?docid=A1400055.EMM | title= EMMI Decree substances or groups of compounds classified as new psychoactive substances | publisher= Wolters Kluwer | date= 1 January 2015 | access-date= 5 August 2020 | archive-date= 8 August 2020 | archive-url= https://web.archive.org/web/20200808213352/https://net.jogtar.hu/jogszabaly?docid=A1400055.EMM | url-status= dead }}</ref> and, as of 26 August 2020, Italy added phenibut to its New Psychoactive Substances ban list.<ref name="Gazzetta Ufficiale 11/08/20"/> As of 18 September 2020, France added phenibut to the controlled psychoactive substances list, prohibiting production, sale, storage, and use.<ref>{{Cite web |url=https://www.legeneraliste.fr/actu-medicale/sante-publique/le-phenibut-interdit-en-france |title=Le phénibut interdit en France {{!}} Le Généraliste |work=Le Généraliste |access-date=28 April 2021 |archive-date=22 January 2021 |archive-url=https://web.archive.org/web/20210122213622/https://www.legeneraliste.fr/actu-medicale/sante-publique/le-phenibut-interdit-en-france |url-status=live }}</ref>

In the United States, phenibut is an unapproved drug, but is often misleadingly marketed as a dietary supplement. It is readily available without a prescription.<ref>{{cite journal |vauthors=Penzak SR, Bulloch M |title=Phenibut: Review and Pharmacologic Approaches to Treating Withdrawal |journal=J Clin Pharmacol |volume=64 |issue=6 |pages=652–671 |date=June 2024 |pmid=38339875 |doi=10.1002/jcph.2414 |type=Review}}</ref><ref>{{cite journal |vauthors=Jouney EA |title=Phenibut (β-Phenyl-γ-Aminobutyric Acid): an Easily Obtainable "Dietary Supplement" With Propensities for Physical Dependence and Addiction |journal=Curr Psychiatry Rep |volume=21 |issue=4 |pages=23 |date=March 2019 |pmid=30852710 |doi=10.1007/s11920-019-1009-0 |url=}}</ref>

In Alabama, phenibut was made a Schedule II substance at the state level in November 2021.<ref>{{cite web|url=https://www.alabamapublichealth.gov/blog/assets/controlledsubstanceslist.pdf|title=Controlled Substances List; Schedule II, page 70|date=22 February 2024|publisher=Alabama State Board of Health|accessdate=13 September 2024|archive-date=8 August 2024|archive-url=https://web.archive.org/web/20240808233205/https://www.alabamapublichealth.gov/blog/assets/controlledsubstanceslist.pdf|url-status=live}}</ref>

==References== {{Reflist|30em}}

{{Navboxes | title = Medical uses | titlestyle = background:#ccccff | list1 = {{Anxiolytics}} {{Hypnotics/sedatives}} {{Insomnia pharmacotherapies}} {{Treatment of drug dependence}} }} {{Navboxes | title = Recreational uses | titlestyle = background:#ccccff | list1 = {{Euphoriants}} {{Recreational drug use}} }} {{Navboxes | title = Pharmacodynamics | titlestyle = background:#ccccff | list1 = {{GABA receptor modulators}} {{Ion channel modulators}} }}

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