Seizure Occurring During Baclofen Monotherapy for Phenibut Withdrawal

Abstract

ObjectivePhenibut is a widely available gamma-aminobutyric acid B receptor agonist. When taken chronically, phenibut causes dependence and subsequent withdrawal if stopped. Baclofen, a gamma-aminobutyric acid B receptor agonist structurally related to phenibut, has been used to manage phenibut withdrawal (PW), although baclofen doses for PW are not well defined and may exceed Food and Drug Administration–approved doses. Little data described outcomes from baclofen use.MethodsThis case details a patient who experienced a seizure while on baclofen 10 mg thrice daily as monotherapy for PW and highlights a potential risk of underdosing baclofen as monotherapy in the management of PW.ResultsA man in his early 30s with anxiety, depression, and substance use disorder presented to the emergency department by family for lethargy and confusion starting earlier that day. He had been using 25–30 g of phenibut daily for the past 6 months. On arrival, he was hypertensive, tachycardic, tachypneic, and lethargic. The patient received 1 mg of intravenous lorazepam and was admitted to the hospital for presumed PW. His symptoms improved overnight, and he was discharged on 10 mg of baclofen thrice daily. He returned 28 hours later after having a seizure and required intensive care admission in addition to multimodal drug therapy.ConclusionsPhenibut use is rising, and treatment options for PW, such as baclofen, warrant additional study. Potential risks of underdosing baclofen if used as monotherapy in PW may include seizures as withdrawal progresses. Baclofen's role in therapy may be more appropriate as an adjunct than a cornerstone of therapy. Treatment done in consultation with providers experienced in managing withdrawal such as a toxicologist may help reduce this risk.

Phenibut: Review and Pharmacologic Approaches to Treating Withdrawal

“…8,32,40,50 Palpitations, tachycardia, dizziness, muscle spasms, paranoia, inducible clonus, and seizures have also been observed. 2,6,37,42,43,49,51,54,55,62 As noted above, some of these symptoms may also occur during phenibut intoxication; they are also consistent with symptoms of intoxication or withdrawal from other medications. In some patients, the collection of symptoms may mimic serotonin syndrome.…”

“…However, this approach has been questioned, especially in patients who may be at risk of seizures. 54 Fortunately, there were no reported seizures in any of the published cases after baclofen initiation. However, given the known risk for seizures with of baclofen, caution should be taken when it is used.…”

“…The mean (range) daily baclofen dose that was used when initiating a tapering regimen was 46.5 mg (15 to 130 mg). Durations ranging from days to 6 months have been used 8,32,[36][37][38][39]41,43,[45][46][47]53,54,56,[58][59][60][61] A baclofen dose of 8-10 mg per gram of phenibut has been suggested for replacement therapy to treat phenibut withdrawal. 8 Other clinicians report having used lower baclofen doses with success, especially if other CNS depressants (ie, benzodiazepines or phenobarbital) are coadministered.…”

“…Phenobarbital was the lone/primary TX in 2 cases. One duration of TX was 8 days; others were not reported 37,38,44,53,54,56,58 Phenobarbital has shown less agitation and delirium compared with benzodiazepines when used to treat alcohol withdrawal. 79,80 Phenobarbital has a longer half-life than lorazepam and diazepam, which may be advantageous when tapering therapy…”

“…Lorazepam (n = 13), with repeated doses up to 16 mg/day acutely (1 patient was maintained on 10 mg/day) and diazepam (n = 7), with repeated doses up to 50 mg/day acutely, were the 2 most commonly administered benzodiazepines; others include chlordiazepoxide (n = 2), clonazepam (n = 2), oxazepam (n = 1), delorazepam (n = 1), midazolam (n = 1), and nitrazepam (n = 1). 32,[36][37][38][39][40][41][42][45][46][47][48][51][52][53][54][55][56][57][58][59][60]62 Benzodiazepines were typically used in the first 24 hours to treat symptoms of anxiety and insomnia. In 4 cases benzodiazepines were used as monotherapy.…”