Clinical Reference
Published Phenibut Overdose & Intoxication Reports
This page is a clinical and emergency reference for physicians and toxicologists assessing a suspected phenibut exposure. It links to published case reports and surveillance data. It is hazard and emergency information — it is not dosage, usage, or consumption guidance, and it underscores that the material must not be ingested.
Published reports
Phenibut Overdose — Nedzlek & Michaelis (2022)
A severe phenibut intoxication involving profound altered mental status and agitation requiring sedation, airway management, and mechanical ventilation. Cureus 14:e23913. Read on PubMed (PMID 35530906).
Phenibut Overdose — Sankary et al. (2017)
An emergency-medicine case report documenting phenibut overdose. Read on PubMed (PMID 27666756).
Phenibut Exposures Reported to a Regional Poison Center — McCabe et al. (2019)
A series of 56 phenibut exposures; eleven patients (19.6%) required intubation, with no deaths in this particular series. American Journal of Emergency Medicine 37(11):2066–2071. Read on PubMed (PMID 30878413).
U.S. Poison Centers — CDC/MMWR (2009–2019)
The largest U.S. surveillance dataset: 1,320 reported phenibut exposures; major effects in 12.6% of cases, coma in 80 patients, and three reported deaths. Read the CDC report.
German Clinical Case Series (2024)
Reports 17 phenibut-related cases, including 15 overdoses, with reported amounts ranging from 2–100 g — illustrating the substantial variability between reported amount and clinical severity. Read on PubMed (PMID 38377332).
Phenibut Intoxication with Other CNS-Active Drugs
A clinical report involving confusion, somnolence, and respiratory depression in a patient with other drug exposures — important because co-ingestants complicate attribution of toxicity specifically to phenibut. Read the case report (PMC10479552).
Important clinical note
There is currently no established human lethal dose for phenibut. Published poison-center data document severe toxicity, coma, intubation, and deaths, while individual case reports also document survival following very large reported exposures. Consequently, an animal LD50 or an individual case report should not be converted into a predicted human lethal dose.
Clinical assessment should therefore be based primarily on the patient’s mental status, airway and respiratory function, cardiovascular status, co-ingestants, chronic phenibut use, usual daily intake, reported acute exposure, and time since the last dose.
U.S. Poison Control: 1-800-222-1222. For significant intoxication, severe withdrawal, respiratory compromise, seizures, profound altered mental status, or uncertain mixed exposure, consultation with Poison Control or a medical toxicologist is appropriate.
For Research Use Only. Not for human or animal consumption. Do not ingest. This clinical reference is provided for hazard, safety, and emergency purposes. Nothing here is dosage or usage guidance, and no statement has been evaluated by the U.S. FDA. See our Disclaimer.