Phenibut

Death may occur when phenibut is combined with depressants such as opiates, benzodiazepines, thienodiazepines or other GABAergic substances. It is strongly discouraged to consume moderate to heavy dosages of these substances together.

This article requires proofreading. As such, it likely contains incorrect grammar, spelling, and punctuation.

Phenibut
Molecular structure of Phenibut
Chemical Nomenclature
Common names	Phenibut, Fenibut, Phenybut, PhGABA
Substitutive name	Noofen
Systematic name	(RS)-4-amino-3-phenyl-butyric acid
Class Membership
Psychoactive class	Depressant
Chemical class	GABAergic
Routes of Administration
Oral Dosage WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section. DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation. This dosage and duration information has been sourced from TripSit Threshold 250 - 300 mg Light 300 - 600 mg Common 600 - 1200 mg Strong 1200 - 1800 mg Heavy 1800 mg + Duration Total 9 - 16 hours Onset 2 - 3 hours

Summary sheet: Phenibut

Phenibut (also known as fenibut, phenybut, Noofen, Citrocard, or β-phenyl-γ-aminobutyric acid) is a central depressant and derivative of the naturally occurring inhibitory neurotransmitter γ-aminobutyric acid (GABA). 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 Post-traumatic stress disorder, anxiety, depression, asthenia, insomnia, alcoholism, stuttering, and vestibular disorders, among other conditions. In the rest 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, pregabalin, and GABOB. In terms of its pharmacology, this compound is classed as a gabapentinoid.

Chemistry

This chemistry section is incomplete. You can help by adding to it.

In terms of chemical structure, phenibut is a derivative of GABA with a phenyl group in the β-position. It is a chiral molecule and thus has two potential configurations, as (R)- and (S)-enantiomers. It has almost the same structure of baclofen (lacking only a chlorine atom in the para-position of the phenyl group) and contains phenethylamine in its structure. Pregabalin has the same structure as phenibut, except that the phenyl group is instead an isobutyl group.

Phenibut HCL, being highly acidic, needs an acidic environment to become unionised and absorbed. Eating will dramatically increase (decrease acidity) of stomach pH. Caffeine promotes gastric acid/H+ secretion into the gut. Thus, an empty stomach coupled with increased gut acidity will dramatically increase the oral absorption of phenibut HCL.

Most commercial phenibut is in the form of the hydrochloride salt (HCL). In this form, the gamma-Aminobutyric acid phenibut is reacted with hydrochloric acid to form a stable, easily dissolvable, acidic, crystalline salt.

Alternatively, phenibut can exist as a Free Amino Acid (FAA). In this form, phenibut is close to pH neutral, non-crystalline, slow to dissolve and mildly bitter. The FAA form has about 20% more phenibut molecules on an equal mass basis compared to phenibut HCL. Phenibut FAA has the advantage of being suitable for sublingual, rectal, or intranasal use, which can be more efficient, faster acting, and predictable for some. Phenibut FAA is converted to phenibut HCL in the stomach. Equal masses of the two forms will have roughly equivalent effects when taken the same way (FAA may be slightly stronger).

Pharmacology

Phenibut has a considerably complex pharmacology in comparison to many other commonly used depressants. It acts as an agonist of the GABA_B receptor (specifically, as a full agonist), similarly to baclofen and GHB, and at higher doses also of the GABA_A receptor. It has some 30- to 68-fold lower affinity for the GABA_B receptor relative to baclofen, which is active at far lower doses in comparison.

Phenibut is also thought to bind to the GABA_A receptor, but according to certain studies, it does not. It is therefore argued that the GABA_A binding likely only occurs at higher concentrations.

Recently, it has been found that phenibut binds to and blocks α2δ subunit-containing voltage-gated calcium channels (VGCCs), similarly to gabapentin and pregabalin. Both enantiomers of phenibut show this action with similar efficacy. Moreover, the R-enantiomer possesses five-fold greater affinity for this site relative to the GABA_B receptor, while the S-enantiomer does not bind to the GABA_B receptor. As such, phenibut is likely to have much greater effect on α2δ subunit-containing VGCCs than on the GABA_B receptor. Notably, the pain relieving effects of phenibut in rodents are mediated not by the GABA_B receptor but by blockade of α2δ subunit-containing VGCCs.

Phenibut has been found to increase dopamine levels within the brain. It was suggested that phenibut may activate dopaminergic processes and that this may be involved in its effects.

In simpler terms, phenibut increases activity within the GABA system through a variety of mechanisms. As the GABA site is the most prolific inhibitory receptor set within the brain, its modulation results in the sedating (or calming effects) of phenibut on the nervous system.

Subjective effects

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. The listed effects will rarely (if ever) occur all at once, but heavier dosages will increase the chances and are more likely to induce a full range of effects.

In comparison to other commonly used GABAgenic depressants such as alcohol or benzodiazepines, this compound is significantly longer lasting, more euphoric and more recreational.

Physical effects

• Stimulation and Sedation - At lower doses, phenibut has a mild physical and mental stimulation effect, encouraging movement, wakefulness, and productivity. At higher doses, however, it becomes physically sedating, encouraging sleep and lethargy. Sleeping after dosing a small amount results in a deep, restful sleep which can leave the user feeling refreshed and alert upon waking.
• Respiratory depression
• Nausea - Phenibut can induce mild to extreme nausea depending greatly on dose and tolerance. It usually manifests roughly 5 hours after the initial dose and generally involves waves of nausea accompanied by excessive sweating and vomiting.
• Increased perspiration
• Motor control loss
• Stomach cramps
• Dizziness
• Dehydration - Dehydration is reported to occur from regular multi-day usage or overdoses.
• Headaches - Moderate to high doses can induce a mild headache many hours after dosing.
• Physical euphoria
• Muscle cramps - Muscle cramps and joint pain are sometimes accompanied at high doses.
• Difficulty urinating - This effect generally only occurs after frequent usage.
• Increased blood pressure
• Temperature regulation loss
• Appetite enhancement

Cognitive effects

• Empathy, love and sociability enhancement - Unlike alcohol which merely increases sociability through disinhibition, phenibut presents strong entactogenic effects which, although much weaker than that of traditional entactogens such as MDMA, are still prominent and well-defined even at light doses.
• Disinhibition
• Information processing suppression - High doses will usually induce a state of mild stupor and confusion.
• Thought deceleration
• Cognitive euphoria
• Motivation enhancement
• Anxiety suppression
• Depression - A low mood can be experienced as an after-effect of high or frequent dosing.
• Amnesia

Toxicity and harm potential

Phenibut likely has a low toxicity relative to dose. However, it is potentially lethal when mixed with depressants like alcohol, benzodiazepines or opioids.

Phenibut hydrochloride is highly caustic and in many sensitive users can cause intestinal discomfort and diarrhoea with some lower digestive tract bleeding. The digestive issues can present themselves within an hour of dosing, or not occur until the next morning. This compound should therefore be taken on an empty stomach as the ionization state of the compound dictates its absorption. After dosing there will be an acute rise in stomach acidity and high doses can cause acid reflux, vomiting, and nausea.

Due to the extremely long come up of phenibut in comparison to other drugs, some users may have an urge to redose as they believe it is not working. This should be avoided to prevent overdose of the drug.

It is strongly recommended that one use harm reduction practices when using this drug.

Tolerance and addiction potential

Phenibut is extremely physically and psychologically addictive.

Tolerance will develop to the sedative-hypnotic effects within a couple of days of continuous use. After cessation, the tolerance returns to baseline in 7 - 14 days. Withdrawal symptoms or rebound symptoms may occur after ceasing treatment abruptly following a few weeks or longer of steady dosing, and may necessitate a gradual dose reduction.

Withdrawal symptoms include severe anxiety, nervousness, hallucinations, tremors, agitation, dizziness, tension, irritation, rapid heartbeat, fatigue, loss of appetite, nausea, vomiting, psychosis, and insomnia.

Phenibut presents cross-tolerance with all GABAgenic depressants, meaning that after its consumption most depressants will have a reduced effect.

Dangerous interactions

Although many drugs are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses of each but still increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.

• Depressants (1,4-Butanediol, 2-methyl-2-butanol, alcohol, barbiturates, GHB/GBL, methaqualone, opioids) - This combination can result in dangerous or even fatal levels of respiratory depression. These substances potentiate the muscle relaxation, sedation and amnesia caused by one another and can lead to unexpected loss of consciousness at high doses. There is also an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
• Dissociatives - This combination can result in an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
• Stimulants - It is dangerous to combine phenibut with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of phenibut, which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of phenibut will be significantly increased, leading to intensified disinhibition as well as other effects. If combined, one should strictly limit themselves to only dosing a certain amount of phenibut per hour. This combination can also potentially result in severe dehydration if hydration is not monitored.

Legal issues

This legality section is a stub. As such, it likely contains incomplete or wrong information. You can help by expanding it.

• United States - Phenibut is uncontrolled, meaning it is legal to possess without any sort of license or prescription.
• United Kingdom - Phenibut is uncontrolled and is legal to possess. The sale, import or export of phenibut may be illegal under the Psychoactive Substance Act, which came into effect on May 26th, 2016.

See also

• Responsible use
• Nootropics
• Gabapentin
• Pregabalin
• Depressants

External links

• Phenibut (Wikipedia)
• Phenibut (Erowid)
• Phenibut (Drugs-Forum)
• Phenibut (Tripsit)
• Phenibut.org