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Received Feb 1, 2018; Accepted Mar 26, 2018
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Background
Phenibut (β-phenyl-γ-aminobutyric acid) is a gamma-aminobutyric acid subtype b (GABA-B) agonist that has both anxiolytic and nootropic activity. Phenibut has been available since the 1960s and is available over-the-counter as a supplement marketed for depression, anxiety, and posttraumatic stress disorder in many parts of the world [1]. Furthermore, it is available without a prescription in retail stores mostly in powder form. Although structurally similar to baclofen (β-(4-chlorophenyl)-GABA), another GABA-B agonist and a commonly prescribed muscle relaxant, it is 30 times less active [1]. In addition, similar to the mechanism of action of gabapentin, a commonly used medication for neuropathic pain, phenibut may decrease the activity of voltage-dependent calcium ionic channels [1, 2].
Tolerance may develop with long-term phenibut use and dosage increases may result in significant side effects. In addition, abrupt discontinuation of phenibut may result in withdrawal which can be severe and require hospitalization. Physical and psychological withdrawal symptoms include anxiety, agitation, decreased appetite, depression, cognitive deficit, fatigue, dizziness, palpitations, insomnia, nausea/vomiting, and tremors. Psychotic symptoms such as auditory/visual hallucinations, disorganization, and delusions have also been reported [3].
Currently, few studies explore the optimal management of phenibut toxicity and withdrawal. Here, we discuss a case of phenibut withdrawal and options for pharmacologic therapy.
2. Case Presentation
A 21-year-old man with a history of anxiety and alcohol abuse presented with three days of insomnia, visual hallucinations, and worsening anxiety after a one-week-long binge of alcohol and concurrent phenibut use. He reported a four-year history of week-long alcohol binges followed by brief periods of sobriety; however, he denied ever experiencing symptoms of alcohol withdrawal. The patient first purchased powdered phenibut from an online retailer several months prior to presentation, reportedly in order to alleviate his anxiety and help him to focus on his schoolwork. He took about one scoop (100–300 mg) as labeled on the product he had, every few days. During an alcohol binge one week prior to admission, the patient began adding one scoop of phenibut to each alcoholic...