OBJECTIVE: Phenibut (4-amino-3-phenyl-butyric acid) is a structural analog of GABA with central nervous system depressant and anxiolytic properties, developed in the former Soviet Union for anxiety, insomnia, and alcohol withdrawal. Its primary mechanism of action is believed to be a GABA-B receptor agonist-with high affinity at the α 2 δ subunit-containing voltage-dependent calcium channels and therefore gabapentinoid activity-as well as, to a lesser extent, GABA-A agonist activity. While not approved or regulated by the FDA, phenibut is easily obtainable online, where it is marketed as a nootropic, or cognitive enhancer. However, phenibut can lead to problems related to intoxication, dependency, and withdrawal, similar to other sedatives.
METHODS: We present a case of phenibut intoxication and withdrawal delirium that provided diagnostic and management challenges because of a patient that was initially not forthcoming about his phenibut use which resulted in five presentations to the hospital including two admissions.
RESULTS: Initial differential including adrenergic, serotonergic or anticholinergic toxidrome based on clinical picture and history reported at that time, however phenibut use of 50 g daily was eventually revealed, an amount exceeding the highest reported cases in our review of the English literature.
CONCLUSIONS: High-dose phenibut intoxication and withdrawal can appear as dramatic and dangerous as high-dose sedative withdrawal, however given its specified receptor affinity and binding profile we found that a pharmacotherapeutic approach targeting GABA-B, GABA-A, and gabapentenoid receptors were effective in stabilizing this patient, eventually leading to the patient\'s full and sustained recovery.

Phenibut is a nootropic drug that exerts anxiolytic and antinociceptive effects by acting on the GABAB receptor and the α2-δ subunit of voltage-dependent calcium channels. An increased number of reports of dependence to and intoxication by phenibut purchased online on the one hand and the wide prescription of phenibut in Eastern Europe for more than half a century on the other hand have resulted in a number of controversies regarding its use. In this review, we have summarized currently available information from case reports of phenibut dependence and intoxication and safety data from clinical trials. We included 14 dependence and intoxication case reports (16 patients) and reviewed 11 phenibut clinical trials (583 patients). The clinical symptoms in the case reports included cardiovascular effects, insomnia, anxiety and agitation, hallucinations, and depressed level of consciousness. In addition, the doses used (0.5-100 g/day) were much higher than the recommended daily dose (0.25-2 g/day). An analysis of phenibut side effects described in the clinical trials showed adverse events in only 5.66% of patients, and the most reported side effect was somnolence (1.89%). There are discrepancies in the reported side effects of phenibut in clinical trials compared to those reported in cases of online-purchased phenibut dependence and intoxication. The current systematic review provides evidence that, at therapeutic doses, phenibut is safe and well tolerated with minor adverse effects, but questions regarding the quality of phenibut obtained online and the contribution of alcohol and other drug abuse to phenibut dependence and intoxication remain open.

BACKGROUND: Vascular cognitive impairment (VCI) is a common cause of dementia. Research suggests that hereditary factors (gene mutations) play an important role in the pathogenesis of VCI, and a mutation of the NOTCH3 locus is frequently identified in affected patients. Herein, we report the case of a patient with confirmed VCI associated with a NOTCH3 exon 33 gene mutation and review the relevant VCI literature.
UNASSIGNED: A 48-year-old man presented to our neurology clinic with gradually progressive cognitive impairment.
UNASSIGNED: Brain magnetic resonance imaging revealed multiple punctate hyperintensities in the patient\'s periventricular white matter. Genetic analysis showed a c.6744C > T, p. Ala2223Val substitution in exon 33 of the NOTCH3 gene. We diagnosed thepatient with VCI secondary to a NOTCH3 gene mutation.
METHODS: Donepezil (5 mg) and memantine (5 mg) daily.
RESULTS: The patient showed symptom improvement at his 3-month and 6-month follow-up appointments.
CONCLUSIONS: This patient may have a new type of mutation that is different from the one seen in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, although it involves a NOTCH3 defect. We propose that the entire NOTCH3 gene should be sequenced in patients with suspected hereditary VCI. This practice could facilitate the discovery of newpathogenic mutations and diseases.

A 26-year-old female presented with vision loss accompanied by migraine-like headaches. A contrast-enhanced magnetic resonance imaging of the brain was performed which revealed findings suggestive of stroke-like migraine attacks after radiation therapy (SMART) syndrome. SMART syndrome is a delayed complication of brain radiation characterized by neurologic symptoms including migraine-like headaches, seizures, and hemispheric impairment. The purpose of this article is to make the readers aware of this rare complication of brain irradiation. Appropriate diagnosis of SMART syndrome is essential to avoid invasive tests.

BACKGROUND: Delayed encephalopathy due to carbon monoxide (CO) poisoning can even occur in patients with mild symptoms of acute CO poisoning. Some cases taking conventional hyperbaric oxygen (HBO) therapy or steroid-pulse therapy may be insufficient, and AchEI may be effective.
METHODS: We report two cases of delayed encephalopathy after acute CO poisoning involving two women aged 69 (Case 1) and 60 years (Case 2) whose cognitive function improved with acetylcholinesterase inhibitor (AchEI) treatment. Delayed encephalopathy occurred 25 and 35 days after acute CO poisoning in Case 1 and Case 2, respectively. Both patients demonstrated cognitive impairment, apathy, and hypokinesia on admission.
RESULTS: Although hyperbaric oxygen therapy did not yield any significant improvements, cognitive dysfunction improved substantially. This was evidenced by an improved Mini-Mental State Examination score ffom 9 to 28 points in Case 1 and an improved Hasegawa\'s dementia rating scale score from 4 to 25 points in Case 2 after administration of an AchEI. In Case 1, we administered galantamine hydrobromide, which was related with improved white matter lesions initially detected on brain magnetic resonance imaging. However, in Case 2 white matter lesions persisted despite AchEI treatment. AchEI treatment may result in improved cognitive and frontal lobe function by increasing low acetylcholine concentrations in the hippocampus and frontal lobe caused by decreased nicotinic acetylcholine receptor levels in delayed encephalopathy after CO poisoning.
CONCLUSIONS: Physicians should consider AchEIs for patients demonstrating delayed encephalopathy due to CO poisoning.

BACKGROUND: A possible association between benzodiazepine use and Alzheimer\'s disease (AD) has been hypothesized in previous studies.
OBJECTIVE: Using claims data from the Helsana Group, a large Swiss health insurance provider, we examined the association between previous benzodiazepine use and the risk of AD.
METHODS: We conducted a matched case-control study and identified 1438 incident AD cases between 2013 and 2014 based on recorded first-time use of drugs used to treat AD [i.e., acetylcholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and the N-methyl-D-aspartate receptor antagonist memantine] and matched one control to each case on age, sex, index date, and residence (canton). Because the initiation of benzodiazepine use shortly before the AD diagnosis date may occur as a result of symptomatic treatment of prodromal symptoms of early major neurocognitive disorder, we introduced an induction period of 2 years before the AD diagnosis date. Additionally, we categorized medication use by duration of use prior to the index date using prescriptions. We applied conditional logistic regression analyses to calculate odds ratios with 95% confidence intervals and adjusted for use of antidepressants.
RESULTS: The crude odds ratio (95% confidence interval) of developing AD for patients starting benzodiazepine treatment was 1.71 (1.17-2.99) in the year before diagnosis and 1.19 (0.82-1.72) in the third year before diagnosis. After accounting for benzodiazepine use initiated during the prodromal phase, benzodiazepine use was not associated with an increased risk of developing AD; long-term benzodiazepine use (≥30 prescriptions) yielded an adjusted odds ratio of 0.78 (0.53-1.14).
CONCLUSIONS: After taking into consideration a possible protopathic bias in the 2 years preceding the AD diagnosis date, benzodiazepine use was not associated with an increased risk of developing AD.

BACKGROUND: Aromatic l-amino acid decarboxylase (AADC) deficiency is an autosomal recessive disorder, caused by defects in the DDC gene. AADC catalyzes the synthesis of the neurotransmitters dopamine and serotonin from l-dopa and 5-HT respectively. Most patients are bed ridden for life, with little response to treatment. We now report one female patient who improved her motor and cognitive function after being prescribed a MAO-B inhibitor.
METHODS: A five years old female presented with the typical clinical features of AADC deficiency. She was floppy, with no head control, had intermittent limb dystonia, and an upward deviation of the eyes (oculogyric crisis). This patient possessed compound heterozygous mutations in DDC (p.Trp105Cys, p.Pro129Ser), with a CSF draw indicating abnormal patterns of biogenic amine metabolites, compatible with AADC deficiency.
RESULTS: After her diagnosis at 3years of age, medication with levodopa and vitamin B6 failed to show any efficacy. Subsequent administration with a MAO-B inhibitor improved her psychomotor functions to the extent that at 5years of age she could walk several meters with support.
CONCLUSIONS: Our analyses of chemical findings, together with in silico structure predictions, lead us to hypothesize that this patient retained some AADC activity. In these cases, accurate diagnosis and early treatment should improve patient outcome.

Obsessive-compulsive disorder (OCD) is one of the most common and disabling psychiatric disorders. Treatment with serotonin selective reuptake inhibitors (SSRIs) shows significant improvement; however, residual symptoms remain in most patients despite continued adequate OCD treatment. For patients exhibiting partial or no response to multiple SSRIs, augmentation strategies are usually recommended. Here, we introduce a retrospective consecutive sample of aged patients with resistant OCD treated with donepezil augmentation to regular pharmacotherapy.
METHODS: Ten patients (5 males, 5 females; mean [SD] age, 63.8 [7.5] years), suffering from resistant OCD, were openly treated with donepezil 10 mg/d as add-on. Efficacy was assessed at baseline and after 8 weeks of treatment using the Yale-Brown Obsessive Compulsive Scale, Clinical Global Impression-Severity, and Clinical Global Impression-Improvement.
RESULTS: The treatment was generally well tolerated without adverse events. In all patients, mean (SD) Yale-Brown Obsessive Compulsive Scale scores diminished from 27.3 (4.3) points at baseline to 16.9 (4.5) points at week 8 (P < 0.0001). Mean (SD) Clinical Global Impression-Severity scores diminished from 5.5 (0.7) points to 3.1 (1.0) points, (P < 0.001). According to Clinical Global Impression-Improvement, 7 patients demonstrated \"very much\" or \"much\" improvement and 3 patients did not demonstrate any improvement.
CONCLUSIONS: Donepezil was a well-tolerated add-on to regular pharmacotherapy in treatment-resistant OCD patients in this small cases series. Donepezil could be a promising optional therapy for patients suffering from resistant OCD, but further randomized controlled studies are necessary.

OBJECTIVE: Reports of manic episodes associated with the use of cholinesterase inhibitors (including donepezil) are limited. Despite the previous notion of procholinergic drugs potentially inducing depression, the contemporary evidence for cholinesterase inhibitors appears to also indicate a trend for elevated mood (in patients with or without a history of depressive disorder).
METHODS: Case report.
RESULTS: The authors report a case of a manic episode with psychotic features associated with the up-titration of donepezil in a patient with Alzheimer\'s disease and a distant history of major depression but without a preexisting bipolar disorder.
CONCLUSIONS: Pathophysiology of donepezil-induced mania appears to contradict the traditional cholinergic-adrenergic hypothesis. Donepezil-associated mania should be suspected after donepezil initiation/dose up-titration when correlated to new onset of mania. Donepezil should be used more cautiously in patients with current or previous mood episodes or in those who are otherwise at high risk for manic episodes (e.g., cerebrovascular disease). Although this requires further investigation in different patient populations, there may be subtypes of older patients with neurocognitive disorders who are particularly vulnerable to activation effects of cholinesterase inhibitors.

An 80-year-old woman with Alzheimer\'s dementia presented with diarrhoea, vomiting and worsening confusion following an increase in donepezil dose from 5 to 10 mg. The ECG revealed prolongation of QTc interval. Soon after admission, she became unresponsive with polymorphic ventricular tachycardia (VT). Cardiopulmonary resuscitation with a 200 J shock was successful in establishing cardiac output. Following the discontinuation of donepezil, the QTc interval normalised and no further arrhythmias were recorded. Treatment with anticholinesterase inhibitors may result in life-threatening VT. Vigilance is required for the identification of this condition in patients presenting with presyncope, syncope or seizures.