Phenibut - Lyrica (Pregabalin) Interaction
Herbal: Phenibut
Also Known As: Beta-phenyl-gamma-aminobutyric acid, 4-Amino-3-Phenylbutyric Acid, B-(Aminomethyl)-Benzenepropanoic Acid, Beta-(Aminomethyl)-Hydrocinnamic Acid, B-Phenyl-Gamma-Aminobutyric Acid, Beta-Phenyl-GABA, Beta-Phenyl-Gamma-Aminobutyric Acid, Fenibut, Phénibut, Phenigam
Drug: Pregabalin
Brand names:
Lyrica, Lyrica CR

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Pregabalin is classified as belonging to the following category: Cns Depressants
Theoretically, phenibut might increase the risk of sedation and respiratory depression when taken with CNS depressants.
Phenibut has been associated with sedation and respiratory depression in several case reports, especially when taken at high doses.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Downes MA, Berling IL, Mostafa A, Grice J, Roberts MS, Isbister GK. Acute behavioural disturbance associated with phenibut purchased via an internet supplier. Clin Toxicol (Phila). 2015;53(7):636-8.
- O'Connell CW, Schneir AB, Hwang JQ, Cantrell FL. Phenibut, the appearance of another potentially dangerous product in the United States. Am J Med. 2014 Aug;127(8):e3-4.
- Sankary S, Canino P, Jackson J. Phenibut overdose. AM J Emerg Med. 2017 Mar;35(3):516.e1-516.e2.
- Graves JM, Dilley J, Kubsad S, Liebelt E. Notes from the field: phenibut exposures reported to poison centers - United States, 2009-2019. MMWR Morb Mortal Wkly Rep 2020;69(35):1227-8.
Interaction Details
Pregabalin is classified as belonging to the following category: Pregabalin (Lyrica)
Theoretically, phenibut might increase the risk for additive adverse effects, including sedation, when taken with pregabalin.
Phenibut is structurally related to pregabalin, and both chemicals act at GABA receptors in the brain. In a case report, a patient who had experienced tolerance to the effects of pregabalin for treatment of chronic neuropathic pain experienced a reduction in tolerance when phenibut was taken concurrently.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Tamarelli C, Hosanagar A. Phenibut use in a patient prescribed gabapentinoids (letter). Pain Med 2020; Aug 4:pnaa205. doi: 10.1093/pm/pnaa205.
Phenibut Overview

Pregabalin Overview
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Pregabalin capsules, oral solution (liquid), and extended-release (long-acting) tablets are used to relieve neuropathic pain (pain from damaged nerves) that can occur in your arms, hands, fingers, legs, feet, or toes if you have diabetes and postherpetic neuralgia (PHN; the burning, stabbing pain or aches that may last for months or years after an attack of shingles). Pregabalin capsules and oral solution are also used to relieve neuropathic pain that can occur after a spinal cord injury and to treat fibromyalgia (a long-lasting condition that may cause pain, muscle stiffness and tenderness, tiredness, and difficulty falling asleep or staying asleep). Pregabalin capsules and oral solution are used along with other medications to treat certain types of seizures in adults and children 1 month of age and older. Pregabalin is in a class of medications called anticonvulsants. It works by decreasing the number of pain signals that are sent out by damaged nerves in the body.
Phenibut - More Interactions
Phenibut interacts with 247 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.