Article

Phenibut overdose

Case Report

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American Journal of Emergency Medicine

journal homepage: www. elsevier. com/ locate/ajem

Phenibut overdose

Abstract

A 25-year-old white man presented to the emergency department with altered mental status and stupor. He and his girlfriend were dropped off at the triage entrance by a friend who was concerned after he started behaving erratically, became confused, and possibly had “walk- ing seizures.” He was limp with a decreased level of consciousness and was quickly rushed back to the resuscitation room. The friend stated that the patient had recreationally ingested phenibut pills, which were obtained over the Internet. At this time, no further medical history was available. Physical examination revealed a blood pressure of 121/61, pulse of 60, rectal temperature of 35.3?C, and a respiratory rate of 10 breaths per minute. In general, he was somnolent but arousable with sternal rub. Pupils were dilated to 8 mm bilaterally and were sluggishly reactive. Respirations were shallow without wheezing. Cardiac and Abdominal examinations were benign. The Glasgow Coma Scale was 10 (E2M3V5).

Initial workup revealed a fingerstick glucose of 101 mg/dL and normal complete blood count and comprehensive metabolic profile. His Creatinine kinase was 689 U/L, and urine drug screen was negative. His alcohol level was less than 3 g/dL. Arterial blood gas revealed pH 7.35, pCO2 55, and pO2 114 on 34% fraction of inspired oxygen. Chest x-ray and electrocardiogram were unremarkable. Given the patient’s decreased level of consciousness, he was immediately administered naloxone 1 mg intravenous (IV) without significant clinical improvement. He was covered in warm blankets and received warm IV fluids. The Poison Control Center was consulted for additional information on phenibut and clinical management recommendations.

Phenibut (?-phenyl-?-aminobutyric acid) is an anxiolytic and noot- ropic drug developed in Russia during the 1960s. It is a GABA analog synthesized with an additional phenyl group to facilitate passage through the blood-brain barrier. It has been demonstrated to exert its effects primarily through GABAB receptor agonism [1]. The drug gained prominence when it was included as standard supply in medical kits for cosmonauts on Russian space flights. It was valued for its high tranquil- izing properties and reports of enhanced cognition [2]. Although there is no approved clinical use of phenibut in the United States, the drug is currently marketed as a nutritional supplement aid for anxiety, insom- nia, and cognitive enhancement as well as a mood booster [3]. The Inter- net has played a key role in the accessibility and distribution of phenibut, with most patients easily obtaining the substance through on- line retailers. The first report of phenibut intoxication in the United States occurred in 2010 after a patient used it to self-medicate for anx- iety [4].

The most commonly desired effects of phenibut include the disappearance of social anxiety, hypnosis, and a sense of euphoria [5].

In almost all case reports of phenibut use, patients reported histories of depression, anxiety, insomnia, or concomitant substance abuse [5].

Drug tolerance has been shown to develop within 1 to 2 weeks of phenibut use [5,6]. Cases of acute intoxication usually involve individuals taking Large doses in an attempt to regain the desired effects after drug tolerance develops. Doses as low as 3 g daily for 4 days and as high as a single 30-g dose have been implicated in phenibut intoxication [7,8].

The most common symptom of phenibut intoxication is a stuporous or lethargic altered mental status, often accompanied by dystonia and hypothermia. Pupillary dilation has also been described. The respiratory effects have been mixed from benign to requiring intubation [8,9]. The remainder of the physical examination is benign in most case reports, although hypertension and tachycardia have been noted.

Diagnosis of intoxication is dependent on an accurate history. Physical examination findings of altered mental status, dystonia, and hy- pothermia are not specific to phenibut. Similar findings are seen more commonly with GHB (?-hydroxybutyrate) intoxication. There are no blood or Urine tests available for diagnosis of phenibut intoxication. In one case, intoxication was confirmed using liquid chromatography- tandem mass spectrometry, which is not readily available [10]. There is no known antidote, and management consists of supportive care until the drug is naturally eliminated. Animal models have demonstrated that phenibut is not metabolized, but renally excreted [3]. Almost all cases of phenibut intoxication involve oral administration [5]. Clinicians should have a low threshold for intubation and monitoring in the intensive care unit setting if patients appear at risk for apnea, hypoxia, or aspiration. Most phenibut intoxications resolve within 24 hours [5].

It also appears that there is greater public awareness of phenibut, and with ease of online access, this may portend a greater incidence of phenibut intoxication. This may result in diagnostic and therapeutic challenges to emergency departments and require a greater index of suspicion.

Our patient received supportive care and was admitted to the inten- sive care unit. He was treated primarily with IV fluids to enhance phenibut’s renal excretion. When he became more awake, he left against medical advice.

Seth Sankary, MS4? Peter Canino, MS4 Jennifer Jackson, MD

University of Miami, Miller School of Medicine, Miami, FL

?Corresponding author

E-mail address: [email protected]

http://dx.doi.org/10.1016/j.ajem.2016.08.067

0735-6757/(C) 2016

References

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  2. Neumyvakin I, Krupina T, Polevoi L, Semeikina L. Principles for making up pharmaceutical kits to supply cosmonauts with drug packs. Kosm Biol Aviakosm Med 1978;12:27.
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