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Phenibut – abuse, addiction & recovery

Home Substance Guide Phenibut – abuse, addiction & recovery

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What is phenibut?

Phenibut (β-phenyl-Ὑ-aminobutyric acid) is a neuropsychotropic drug discovered and developed in the Soviet Union in the 1960s. Given early on to Soviet astronauts to attain relaxation and focus, it is now widely prescribed throughout Eastern European countries like Russia, Latvia, Ukraine and Kazakhstan, where it is known under various trade names such as Noofen, Fenibut and Anfiven.

How does phenibut work?

Its chemical structure is similar to the neurotransmitter GABA, binding to some of the same receptors and producing some of the same effects. Phenibut crosses the blood-brain barrier more effectively than GABA, reducing neural excitability, depressing the central nervous system and thereby inducing a relaxing state and euphoria in high enough doses.

What does phenibut feel like?

Its felt effects are principally tranquilizing: reducing stress, boosting mood and easing sleep. At certain dosages, it can create a sense of well-being and euphoria, potentially leading to an addiction similar to benzodiazepines.

What is phenibut used for?

Phenibut is used chiefly for its anxiolytic (anti-anxiety) effects. Prescribed primarily to treat anxiety disorders in general and social anxiety in particular, other indications include insomnia, pre- and post-operative medication, depression, asthenia (abnormal physical weakness or lethargy), post-traumatic stress disorder, stammering, vestibular or balance disorders, alcoholism, alcohol withdrawal, Menière’s disease, vertigo and motion sickness.

What does phenibut do?

Apart from its main use as an anxiolytic, the two other commonly reported categories of use are euphoric (‘getting high’) and nootropic (to enhance cognitive abilities).

Because phenibut, particularly at low doses, increases dopamine levels, it is sought for its euphoric effects, including greater perceived sociability and mood enhancement.

Its claimed nootropic (so-called “smart drug”) qualities account in part for its popularity on the internet marketplace, with consumer-users reporting augmented focus, alertness and recall.

Is phenibut legal?

In Russia and other Eastern European countries, phenibut is a legal, prescription tranquilizer, used to treat the conditions specified above.

In the United States and the European Union, it is unscheduled and unregulated, neither medically prescribed nor prohibited by law. The reason, in the U.S context, is that phenibut is essentially a chain of amino acids, leading to its classification by the FDA as a dietary supplement tantamount to vitamins and minerals. Consequently, online vendors can sell phenibut legally and in the absence of regulation. However, this should not be confused with it being viewed as a safe supplement or medication. Phenibut has been identified as a drug of abuse with numerous clinical effects in overdose and a withdrawal syndrome with chronic use.

How much phenibut is too much?

Factors such as individual tolerance, contraindications and co-ingested substances, among others, affect its safety. Between 2009-2019 U.S. poison centers reported calls about concerns with phenibut poisonings for patients ingesting 700 mg or more at a time.

Phenibut overdose symptoms

With increased dosages, there is a risk of overdose, including symptoms such as drowsiness, nausea, vomiting, lower blood pressure, psychosis, kidney impairment and liver degeneration.

In severe cases, phenibut overdose can cause seizures and death.

How long does it take for phenibut to kick in?

On average, it takes about two hours to feel the effects of phenibut, when swallowed in capsule form or as a powder mixed with a liquid. However, activation time varies according to the route of administration, with sublingual consumption (placed under the tongue and thereby absorbed into the blood through the skin there) being faster, at an average rate of 30 minutes. Its peak effects emerge, on average, four to six hours after ingestion.

How long does phenibut last?

The duration of phenibut depends on various relative factors, like age, body size, dosage amount and tolerance. In general, however, its primary effects last on average between two and five hours after activation.

How long does phenibut stay in your system?

Phenibut has a half-life of approximately five hours. Half-life is the amount of time it takes for 50% (or half) of a drug’s active substance to be metabolized in your body. That means that the concentration of it in the body is cut to half the original dosage at around five hours after the initial intake. For example, a dosage of 250 mg would reduce to 125 mg.

It’s important to know that the other half isn’t metabolized in another five hours. The half-life process continues, taking 50% of the remaining drug out of your system at each interval. In this case, after another five hours, half of the remaining 125 mg is metabolized out of your system, leaving approximately 62.5 mg in your system.

Therefore, following consumption of 250 mg of phenibut, there would still be a small amount in the body for as long as 36 hours later—although this can vary according to the length of time over which it has been taken, a person’s metabolism, etc.

It remains detectable in the body for up to 26 hours, though this can vary according to the length of time over which it has been taken.

How addictive is phenibut?

Like most substances with potential for abuse, phenibut use carries with it a risk of both physical and psychological dependence, tolerance and withdrawal, which do not take long to develop—in certain cases, after a few times.

Physical dependence arises out of increased stimulation of GABA and dopamine receptors, which induce euphoric effects and can thereby give rise to patterns of compulsion and abuse.

In severe cases, physical dependence can be life threatening due to the possibility of seizures, hallucinations and psychosis. So great care needs to be taken to discontinue use, preferably under medical supervision.

Psychological dependence stems from the habituated reliance on phenibut to perform certain cognitive tasks, engage in social interaction, or simply to sleep, among other behaviors. There emerges a felt sense that the substance is needed to continue involvement in these activities.

When does phenibut withdrawal start?

Once a dependence and tolerance are formed, withdrawal symptoms follow upon suddenly stopping—within several hours to several days.

Withdrawal from phenibut is similar to that of benzodiazepines. The most common withdrawal symptoms are rebound effects, that is, more severe reoccurrences of the symptoms (anxiety, etc.) which the substance was originally used to treat. Anxiety and insomnia are common rebound effects for phenibut.

For long-term users whose nervous systems no longer produce healthy levels of GABA on its own, as well as producing lower levels of dopamine and other related neurotransmitters, withdrawal can start as soon as the remaining amount of phenibut has left their bodies. For other users, withdrawal can begin several days after use is discontinued. Withdrawal symptoms can include anxiety, insomnia, depression, agitation, tachycardia (high heart rate), psychosis, fatigue and loss of appetite.

How long does phenibut withdrawal last?

Phenibut withdrawal symptoms vary according to the frequency and amount of use, taper schedule and interaction with other substances or supplements. Acute symptoms usually last between two days and two weeks.  Lingering effects, however, can persist for several weeks, hinging on the degree of dependence and tolerance effected by long-term consumption. In some severe cases, post-acute withdrawal symptoms (PAWS) could emerge, lasting for as long as 24 weeks. Phenibut PAWS symptoms are frequently psychological, surrounding the symptoms of anxiety and depression.

How to taper off phenibut?

Any attempt to taper or wean off of phenibut should be done under the supervision of a physician or qualified clinician. Further care might also be warranted to treat the co-occurring mental health issues which contributed to the abuse of phenibut in the first place.

Medically trained staff can help safely circumvent or mitigate withdrawal symptoms through a gradual taper schedule and the use of other, non-addictive drugs to make you more comfortable during the withdrawal process.

Medication assisted treatment (MAT) for phenibut withdrawal includes taper medications as well as comfort medications to address anxiety and agitation.

If you or a loved one are concerned about a potential problem with phenibut and would like support in stopping, call Recovery Centers of America (844-242-7956) now, where immediate, expert help is available 24 hours/day, 365 days/year.



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