Phenibut

Phenibut
Clinical data


Trade names	Noofen
Routes of administration	Oral
ATC code	N06BX22 (WHO)
Legal status
Legal status	US: Not FDA approved; unscheduled
Pharmacokinetic data
Bioavailability	64–65%
Biological half-life	5.3 hours (after 250 mg dose)
Identifiers
IUPAC name 4-Amino-3-phenylbutanoic acid
Synonyms	Fenibut, Fenigam, Phenigam, Phenybut, Phenygam, Phenylgamma, PHG, PhGABA
CAS Number	1078-21-3^N
PubChem CID	14113
ChemSpider	13491^Y
UNII	T2M58D6LA8
ChEMBL	CHEMBL315818^Y
ECHA InfoCard	100.012.800
Chemical and physical data
Formula	C₁₀H₁₃NO₂
Molar mass	179.216 g/mol
3D model (Jmol)	Interactive image
Melting point	253 °C (487 °F)
SMILES O=C(O)CC(c1ccccc1)CN
InChI InChI=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)^Y Key:DAFOCGYVTAOKAJ-UHFFFAOYSA-N^Y
^NY (what is this?)

Phenibut (fenibut, phenybut; brand names Noofen and Citrocard), contracted from β-phenyl-γ-aminobutyric acid (β-phenyl-GABA), is a central depressant and analog of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), or a GABA analogue. The addition of a phenyl ring allows phenibut to cross the blood–brain barrier. Phenibut was developed in the Soviet Union in the 1960s, and has since been used there as a pharmaceutical drug to treat a wide range of ailments, including posttraumatic stress disorder, anxiety, depression, asthenia, insomnia, alcoholism, stuttering, and vestibular disorders, among other conditions. In some other parts of the world, phenibut is not approved for clinical use, and is instead sold as a nutritional supplement. It has been reported by some researchers to possess nootropic actions for its ability to improve neurological functions, but others have not observed these effects. It is generally accepted that phenibut has anxiolytic effects in both animal models and in humans.

Phenibut is a close structural analogue of GABA, as well as of baclofen (β-(4-chlorophenyl)-GABA), pregabalin (β-isobutyl-GABA), and GABOB (β-hydroxy-GABA). Phenibut is believed to act as a selective GABA_B receptor agonist; studies are conflicting as to whether phenibut also acts as a GABA_A receptor agonist. More recently, phenibut has been found to act preferentially as a blocker of α₂δ subunit-containing voltage-gated calcium channels, similarly to gabapentin and pregabalin. As such, by definition, phenibut is a gabapentinoid.