|Common names||F-Phenibut, Fluorophenibut, Fluorobut|
f-phenibut (also known as fluorophenibut, and fluorobut) is a central nervous system depressant and closely related structural analog of phenibut. f-phenibut possesses an effect profile similar to phenibut but with a faster onset, significantly increased potency, and shorter total duration. it has recently become available through online research chemical vendors, although little is known about this substance, particularly its potential toxicity and addiction potential.
the substance can be classified as a gabapentinoid, a class which contains other substances such as gabapentin, pregabalin , baclofen, and gabob. it is a derivative of the naturally occurring inhibitory neurotransmitter γ-aminobutyric acid (gaba), with an addition of a phenyl ring that allows it to cross the blood–brain barrier.
as with phenibut, f-phenibut is a derivative of gaba, except with a fluorine-substituted phenyl group in the β-position of the molecule. it is a chiral molecule and thus has two potential configurations as (r)- and (s)-enantiomers. it has an almost identical chemical structure to baclofen (only replacing a chlorine with a fluorine atom in the para-position of the phenyl group). additionally, the widely prescribed gabapentinoid pregabalin also possesses a similar structure as phenibut, except that the phenyl group is instead replaced with an isobutyl group.
due to the lack of research regarding the substance, all discussion regarding the pharmacology of it is purely speculation based upon its structural and subjective effect similarities to other depressants or gabapentinoid such as phenibut, gabapentin, and pregabalin.
among other things, it is likely that this compound exerts its effects by binding to the α2δ-1 site of voltage-gated calcium channels in a manner which is similar to that of other gabapentinoids. by binding to this site, f-phenibut may reduce the release of several excitatory neurotransmitters, including glutamate, substance p, acetylcholine, and norepinephrine. this, in turn, increases gabaergic activity. as the gaba system is the most prevalent inhibitory receptor set within the brain, its modulation may be responsible for the relaxing, sedating, and calming effects of f-phenibut on the central nervous system.