Phenibut: A drug with one too many "buts".

Phenibut is a gamma aminobutyric acid derivative with activity at γ-aminobutyric acid (GABA)B, A and β-phenethylamine receptors. It was developed as a drug in the former Soviet Union to overcome anxiety and improve cognitive function in military personnel. In the last decade, it has made inroads into the European and U.S. markets, being marketed for purported nootropic properties. Here, we summarize the current knowledge on phenibut, its toxicology, pharmacology, adverse health effects, and patterns of use. Publications in peer-reviewed journals were searched in PubMed, Web of Science, and Google Scholar databases. Available literature points to adverse side effects associated with intoxication, withdrawal, and addiction to phenibut. Some of these effects can be life-threatening, requiring hospitalization and therapeutic interventions. Supportive efforts are often complicated by a lack of knowledge regarding phenibut's toxicology and pharmacology. Ingestion of phenibut was often associated with concomitant use of other substances of abuse. As control over its online marketing seems unrealistic, current efforts need to be focused on the addition of phenibut to current drug screening tests and the development of generally accepted treatment strategies for phenibut-associated toxicities.