Phenibut

  • β -phenyl- γ - aminobutyric acid
  • (RS )-4- amino-3- phenylbutanoic (IUPAC)
  • Fenibut
  • Phenybut
  • PhGABA

N06BX22

Anxiolytic

GABAB agonist

Fixed

250-253 ° C ( decomposition)

  • Very slightly soluble in water, ethanol and acetone
  • Practically insoluble in diethyl ether

Template: Infobox chemical / molecular formula search available

Phenibut (including β -phenyl- γ -amino butyric acid ) is a chemical compound selected from the group of the phenylethylamine. The derivative of the naturally occurring inhibitory neurotransmitter γ -aminobutyric acid ( GABA) is used as a drug. The additional phenyl ring enables the compound to cross the blood- brain barrier. Phenibut was discovered in the 1960s in the former Soviet Union. Since it is used there, including the treatment of post-traumatic stress disorder, anxiety and insomnia. The active substance is closely related to the muscle relaxant baclofen. In the U.S. Phenibut sold as a dietary supplement.

The name Phenibut is derived from the chemical name " β -phenyl- γ - aminobutyric acid ".

Clinical information

Areas of application

Phenibut is approved in Russia, Latvia and some Eastern European countries for the treatment of

  • Anxiety and restlessness
  • Sleep disorders in the elderly
  • Stuttering and tics in children
  • Meniere 's disease or vestibular vertigo of other cause

And is used as a prevention

  • In motion sickness
  • To avoid a withdrawal syndrome in alcohol withdrawal

Posology and method of administration

The dose varies between the different fields of application. When anxiety and restlessness, the daily dose is between 750 mg and 1500 mg given three times daily dosing. The application period amounts to 2-3 weeks and can be extended if necessary to 4-6 weeks.

Side effects

Especially at the beginning of treatment or when overdose occurs fatigue and nausea. Rarely, allergic reactions. For longer or higher dosed application Phenibut has a hepatotoxic potential corresponding to a liver monitoring may be required.

Cases of development of tolerance and dependence, and withdrawal symptoms have been described in the literature.

Pharmacology

Phenibut acts similarly to the structurally related baclofen as an agonist at the GABAB receptor. The active substance is different from benzodiazepines, which act as ligands at allosteric GABAA receptor. In higher doses Phenibut binds possibly also to GABAA receptors. From animal studies, there are indications of an additional dopaminergic mechanism of action.

Phenibut is a chiral molecule and thus has a R- and a S- enantiomer. It is used as a pharmaceutically racemate. (R) Phenibut is the pharmacologically active enantiomer, (R) - Phenibut is not active. The dissociation constants at the GABAB receptor for ( RS)- phenibut, (R ) - baclofen and phenibut are respectively 177 ± 2, 92 ± 3 and 6.0 ± 1 uM. This means, baclofen has the highest affinity for the receptor and racemic phenibut the lowest.

In a single dose of 250 mg Phenibut a plasma half- life of 5.3 h was determined. 65 % of the dose was detected in urine unchanged.

History

AI Herzen Leningrad and at the Institute of Experimental Medicine, Academy of Medical Sciences of the USSR by Professor VV Perekalins team was Phenibut for the first time at the Pedagogical Institute synthesized.

CAS registry number PubChem Anatomical Therapeutic Chemical Classification System Active ingredient Balance (ability) GABA receptor Ligand (biochemistry) Digital Object Identifier
646718
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