Quantity of phenibut in dietary supplements before and after FDA warnings

Abstract

Introduction

Phenibut is used to treat anxiety, insomnia, alcohol withdrawal and other conditions in Russia. The drug, however, has abuse potential and may cause lethargy, delirium, psychosis and coma. In the United States (US), the US Food and Drug Administration (FDA) has never approved the use of phenibut as a prescription medication, but the drug is available over-the-counter in dietary supplements. More than 80 cases of coma and death have been associated with phenibut consumption and withdrawal, and the FDA recently warned that the drug is not permitted in over-the-counter supplements. We designed our study to determine the presence and quantity of phenibut in over-the-counter supplements before and after the FDA warnings.

Methods

Phenibut products were included if they (a) listed phenibut or a synonym as an ingredient on the label, (b) were labeled as a dietary supplement, and (c) were available for sale both before and after the FDA warning. Supplements were analyzed by liquid chromatography time-of-flight mass spectrometry; quantification was performed by isotope dilution method.

Results

Four brands of dietary supplements labeled as containing phenibut met the inclusion criteria. Prior to the FDA warnings, two of the four brands contained phenibut, at dosages of 484 mg and 487 mg per serving. After the FDA warning, all four products contained phenibut, ranging in dosages from 21 mg to 1,164 mg per serving. Phenibut was first detected only after the FDA warnings in two brands, and the quantity of phenibut increased in three of four products after the FDA warnings. Quantities detected per dose were as much as 450% greater than a typical 250 mg pharmaceutical tablet manufactured in Russia.

Conclusion

Following FDA issuing an advisory that phenibut is not permitted in dietary supplements, the quantity of phenibut increased in 3 of 4 brands of over-the-counter phenibut supplements.

Keywords:

• Dietary supplements
• phenibut
• FDA

Acknowledgements

The authors thank Patricia Redd, MLS of Cambridge Health Alliance and Paul Bain, PhD of Harvard Medical School for their expert assistance in obtaining obscure references.

Disclosure statement

Dr Gerona and Dr Cohen were subjects of a civil suit brought by Hi-Tech Pharmaceuticals, a supplement company, regarding β-methylphenylethylamine; Dr Gerona’s case was dismissed and the jury found in Dr Cohen’s favor. Dr Cohen has received research support from Consumers Union and PEW Charitable Trusts. Mr. Travis is an employee of NSF International, and some of NSF International’s clients are dietary supplement manufacturers. No other disclosures were reported. Mr. Ellison and Dr. Gaufberg have no conflicts of interest to report.

Additional information

Funding

No funding was received for the research reported in this article.