Herb & supplement monograph

Phenibut Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Phenibut interacts with medications. The heart of this page is the interaction list — every drug Phenibut is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Phenibut is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Phenibut Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, Phenibut drug interactions carry a moderate risk of causing real problems for most people, mainly with medications that slow the brain and cause drowsiness. Every listed interaction is rated moderate, none major or minor, though the documentation comes mostly from case reports and theory rather than controlled human studies.

Interactions deserving the most attention

The combinations that deserve the most care involve CNS depressants, meaning medicines that cause sedation, because Phenibut has been linked in case reports to deep sedation and slowed breathing, especially at high doses, and adding another sedating drug could make that worse. Pregabalin (Lyrica) also stands out, since Phenibut is chemically similar to it and both act on the same calming receptors in the brain, so taking them together may pile on side effects like drowsiness.

What the rest of the list means

The long list of interacting medications largely reflects how many drugs have sedating effects, not hundreds of separate proven problems. Most of these concerns are theoretical or drawn from a handful of case reports, and none have been confirmed in well-controlled human studies. Still, the pattern points consistently in one direction: added sleepiness and slowed breathing are the effects to watch for.

Check your medications against Phenibut

Based on HelloPharmacist’s Phenibut interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Phenibut

248 medications have a known interaction with Phenibut, graded by severity. Select any drug for the full evidence-based detail.

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AI summaries are generated from our Phenibut interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

AcepromazineAtravet

Moderate Cns Depressants