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Owen NE, Barker RA, Voysey ZJ. Sleep Dysfunction in Huntington's Disease: Impacts of Current Medications and Prospects for Treatment. J Huntingtons Dis 2023; 12:149-161. [PMID: 37248911 PMCID: PMC10473096 DOI: 10.3233/jhd-230567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2023] [Indexed: 05/31/2023]
Abstract
Sleep dysfunction is highly prevalent in Huntington's disease (HD). Increasing evidence suggests that such dysfunction not only impairs quality of life and exacerbates symptoms but may even accelerate the underlying disease process. Despite this, current HD treatment approaches neither consider the impact of commonly used medications on sleep, nor directly tackle sleep dysfunction. In this review, we discuss approaches to these two areas, evaluating not only literature from clinical studies in HD, but also that from parallel neurodegenerative conditions and preclinical models of HD. We conclude by summarizing a hierarchical framework of current medications with regard to their impact on sleep, and by outlining key emerging sleep therapies.
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Affiliation(s)
- Natalia E. Owen
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
| | - Roger A. Barker
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Zanna J. Voysey
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
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Schneider F, Darpo B, Loupe PS, Xue H, Knebel H, Gutierrez M, Gordon MF, Rabinovich-Guilatt L. Evaluation of Deutetrabenazine's Potential to Delay Cardiac Repolarization Using Concentration-QTc Analysis. Clin Pharmacol Drug Dev 2023; 12:94-106. [PMID: 36098670 PMCID: PMC10086964 DOI: 10.1002/cpdd.1161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023]
Abstract
Deutetrabenazine (Austedo) is indicated in adults for chorea associated with Huntington disease and tardive dyskinesia. Escalating deutetrabenazine doses were administered to healthy volunteers who were cytochrome P450 2D6 extensive/intermediate metabolizers (EMs) or poor metabolizers (PMs) to determine pharmacokinetic exposure of parent drug and active metabolites (α-dihydrotetrabenazine [α-HTBZ] and β-dihydrotetrabenazine [β-HTBZ]), and collect corresponding electrocardiograms (ECGs) for evaluation of the cardiodynamic effect using concentration-QTc (C-QTc) modeling. Participants (12 EMs, 24 PMs) received placebo or single doses of deutetrabenazine (24, 48, and 72 mg) to achieve plasma concentrations exceeding therapeutic range in both cohorts. Pharmacokinetic samples were obtained over 72 hours after dosing and were time matched with 12-lead ECGs extracted from continuous ECG recordings. C-QTc analysis, using linear mixed-effects modeling and model selection procedure, characterized the relationship between plasma concentrations of deutetrabenazine, deuterated α-HTBZ and β-HTBZ, and the change from baseline in QT interval corrected using Fridericia's formula. Deutetrabenazine exhibited linear kinetics, and a C-QTc model with deuterated α-HTBZ and β-HTBZ was selected to best describe the C-QTc relationship in pooled EM and PM data. This model predicted a placebo-corrected Fridericia corrected QT interval prolongation higher than 10 milliseconds can be excluded at concentrations associated with the maximum recommended doses in both populations. Adverse events increased with higher exposure as reflected by the higher event number in the PM cohort receiving 48 and 72 mg doses. No subject discontinued due to cardiac-related adverse events and no clinically relevant ECG findings were reported. Thus, this study found that deutetrabenazine does not have a clinically relevant effect on QT prolongation at maximum recommended doses in either cytochrome P450 2D6 EMs or PMs.
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Affiliation(s)
| | | | - Pippa S Loupe
- Teva Pharmaceuticals, West Chester, Pennsylvania, USA
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3
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Spontaneous changes in brain striatal dopamine synthesis and storage dynamics ex vivo reveal end-product feedback-inhibition of tyrosine hydroxylase. Neuropharmacology 2022; 212:109058. [DOI: 10.1016/j.neuropharm.2022.109058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/09/2022] [Accepted: 04/05/2022] [Indexed: 11/18/2022]
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Schneider F, Stamler D, Bradbury MJ, Loupe PS, Gordon MF, Rabinovich-Guilatt L. The effect of potent CYP2D6 inhibition on the pharmacokinetics and safety of deutetrabenazine in healthy volunteers. Eur J Clin Pharmacol 2021; 78:11-18. [PMID: 34491372 PMCID: PMC8724172 DOI: 10.1007/s00228-021-03202-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/12/2021] [Indexed: 11/05/2022]
Abstract
Purpose Deutetrabenazine is a deuterated form of tetrabenazine with a confirmed lower rate of CYP2D6 metabolism of the active metabolites, α- and β-HTBZ. In this study, we assessed the effect of paroxetine, a potent CYP2D6 inhibitor, on the pharmacokinetics and safety of deutetrabenazine and its metabolites. Methods In this open-label sequential drug-drug-interaction study, 24 healthy adults who were CYP2D6 extensive or intermediate metabolizers received a single deutetrabenazine 22.5-mg oral dose on days 1 and 11 and a single paroxetine 20-mg oral daily dose on days 4–12. Pharmacokinetics of deutetrabenazine and its metabolites were assessed on days 1–4 and 11–14. Paroxetine trough concentrations were obtained pre-dose on days 9–13. Safety examinations occurred throughout the study. Results Paroxetine administered under steady-state conditions, increased exposure of the deuterated active metabolites, α-HTBZ (1.2-fold Cmax and 1.8-fold AUC0–∞) and β-HTBZ (2.1-fold Cmax and 5.6-fold AUC0–∞), and correspondingly, 1.6-fold Cmax and threefold AUC0–∞ for total (α + β)-HTBZ. Sixteen subjects reported 45 adverse events and most were mild. Headache was the most common AE reported 8 times by 7 subjects (5 following paroxetine alone; 2 following deutetrabenazine + paroxetine). Conclusions Paroxetine-induced increases in exposure to the active deutetrabenazine metabolites were less than those previously reported for tetrabenazine, a finding expected to reduce the burden of drug interaction. In addition, single doses of 22.5 mg deutetrabenazine, when given alone or in the presence of steady-state paroxetine (20 mg daily), were safe. Supplementary information The online version contains supplementary material available at 10.1007/s00228-021-03202-0.
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Affiliation(s)
- F Schneider
- Teva Pharmaceutical Industries Ltd, Ratiopharm GmbH, Ulm, Germany.
| | - D Stamler
- Formerly of Teva Pharmaceutical Industries Ltd, Currently Alterity Therapeutics Limited, Newark, CA, USA
| | - M J Bradbury
- Formerly of Teva Pharmaceutical Industries Ltd, Currently Alterity Therapeutics Limited, Newark, CA, USA
| | - P S Loupe
- Teva Pharmaceutical Industries Ltd, West Chester, PA, USA
| | - M F Gordon
- Teva Pharmaceutical Industries Ltd, West Chester, PA, USA
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Paek SM. Synthesis of Tetrabenazine and Its Derivatives, Pursuing Efficiency and Selectivity. Molecules 2020; 25:molecules25051175. [PMID: 32151010 PMCID: PMC7179236 DOI: 10.3390/molecules25051175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 12/30/2022] Open
Abstract
Tetrabenazine is a US Food and Drug Administration (FDA)-approved drug that exhibits a dopamine depleting effect and is used for the treatment of chorea in Huntington’s disease. Mechanistically, tetrabenazine binds and inhibits vesicular monoamine transporter type 2, which is responsible for importing neurotransmitters from the cytosol to the vesicles in neuronal cells. This transportation contributes to the release of neurotransmitters inside the cell to the synaptic cleft, resulting in dopaminergic signal transmission. The highly potent inhibitory activity of tetrabenazine has led to its advanced applications and in-depth investigation of prodrug design and metabolite drug discovery. In addition, the synthesis of enantiomerically pure tetrabenazine has been pursued. After a series of research studies, tetrabenazine derivatives such as valbenazine and deutetrabenazine have been approved by the US FDA. In addition, radioisotopically labeled tetrabenazine permits the early diagnosis of Parkinson’s disease, which is difficult to treat during the later stages of this disease. These applications were made possible by the synthetic efforts aimed toward the efficient and asymmetric synthesis of tetrabenazine. In this review, various syntheses of tetrabenazine and its derivatives have been summarized.
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Affiliation(s)
- Seung-Mann Paek
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju Daero 501, Jinju, Gyeongnam 52828, Korea
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Sherman CW, Iyer R, Abler V, Antonelli A, Carlozzi NE. Perceptions of the impact of chorea on health-related quality of life in Huntington disease (HD): A qualitative analysis of individuals across the HD spectrum, family members, and clinicians. Neuropsychol Rehabil 2019; 30:1150-1168. [PMID: 30849283 DOI: 10.1080/09602011.2018.1564675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chorea, a hallmark symptom of Huntington's disease (HD), is characterized by jerky involuntary movements affecting the whole body that can interfere with daily functioning and impact health-related quality of life (HRQOL). To characterize chorea's impact on everyday functioning and HRQOL and identify patterns of perception and experiences of chorea among patients, caregivers, and providers. Data from focus groups of individuals with manifest HD (n = 8 early-stage HD; n = 16 late-stage HD), individuals at-risk or prodromal HD (n = 16), family HD caregivers (n = 17), and HD clinicians (n = 25). Focus group recordings were transcribed verbatim and analysed via constant comparison to identify meaningful and salient themes of living with chorea. Global themes of chorea's impact identified included: watching for chorea, experiences of stigma, and constraints on independence and relationships. Themes distinct to specific respondent groups included: Vigilance (at risk, prodromal); adaptation to chorea (early-stage); loss of autonomy and social life (late-stage); monitoring engagement (family caregivers) and safety (clinical providers). Living with chorea significantly constrains daily functioning, interactions, and HRQOL across the HD disease spectrum. Addressing these impacts via appropriate management of chorea can potentially enhance functioning, HRQOL, and overall satisfaction for persons with HD and their families.
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Affiliation(s)
| | - Ravi Iyer
- Teva Pharmaceutical Industries, Frazer, PA, USA
| | | | | | - Noelle E Carlozzi
- Department of Physical Medicine & Rehabilitation, University of Michigan, Ann Arbor, MI, USA
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Abstract
Tardive dyskinesia is a potentially irreversible, debilitating, hyperkinetic movement disorder that can result from dopamine receptor antagonists. Prompt recognition and resolution of symptoms are instrumental in preventing disease irreversibility, though current treatment options have fallen short of robust, effective, and long-term symptom control. In April 2017, the Food and Drug Administration (FDA) approved 2 new vesicular monoamine transporter 2 (VMAT2) inhibitors, deutetrabenazine and valbenazine, for chorea related to Huntington's disease and tardive dyskinesia, respectively. These agents were pharmacologically modified from tetrabenazine, a VMAT2 inhibitor used off-label in the treatment of tardive dyskinesia. Despite FDA-labeled indications of deutetrabenazine and valbenazine, each agent was explored as a treatment option for those with tardive dyskinesia. In this study, the pharmacologic modifications of the 2 new VMAT2 inhibitors are described, with detailed explanation as to how these may impact clinical practice. The associated case series, observational studies, and clinical trials exploring their use in the treatment of tardive dyskinesia are reported with expert opinion on practice implication.
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Affiliation(s)
- Alyssa M Peckham
- 1 Department of Pharmacy Practice, Midwestern University College of Pharmacy-Glendale, Glendale, AZ, USA
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Of rodents and men: understanding the emergence of motor and cognitive symptoms in Huntington disease. Behav Pharmacol 2017; 27:403-14. [PMID: 26886208 DOI: 10.1097/fbp.0000000000000217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Arguably, one of the most important milestones in Huntington disease research since the discovery of the gene responsible has been the generation of different genetic animal models. Although clinical reports have shown evidence of progressive cognitive impairments in gene carriers before motor symptoms are diagnosed, such symptoms have been much less obvious in animal models. In this review, we summarize the three main classes of animal models for Huntington disease and describe some relevant translational assays for behavioural deficits evaluation. Finally, we argue that a good knowledge of the emergence of motor and cognitive symptoms in mice and rat models is indispensable for the selection of endpoint measures in early preclinical drug screening studies.
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Rangel-Barajas C, Rebec GV. Dysregulation of Corticostriatal Connectivity in Huntington's Disease: A Role for Dopamine Modulation. J Huntingtons Dis 2017; 5:303-331. [PMID: 27983564 PMCID: PMC5181679 DOI: 10.3233/jhd-160221] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aberrant communication between striatum, the main information processing unit of the basal ganglia, and cerebral cortex plays a critical role in the emergence of Huntington’s disease (HD), a fatal monogenetic condition that typically strikes in the prime of life. Although both striatum and cortex undergo substantial cell loss over the course of HD, corticostriatal circuits become dysfunctional long before neurons die. Understanding the dysfunction is key to developing effective strategies for treating a progressively worsening triad of motor, cognitive, and psychiatric symptoms. Cortical output neurons drive striatal activity through the release of glutamate, an excitatory amino acid. Striatal outputs, in turn, release γ-amino butyric acid (GABA) and exert inhibitory control over downstream basal ganglia targets. Ample evidence from transgenic rodent models points to dysregulation of corticostriatal glutamate transmission along with corresponding changes in striatal GABA release as underlying factors in the HD behavioral phenotype. Another contributor is dysregulation of dopamine (DA), a modulator of both glutamate and GABA transmission. In fact, pharmacological manipulation of DA is the only currently available treatment for HD symptoms. Here, we review data from animal models and human patients to evaluate the role of DA in HD, including DA interactions with glutamate and GABA within the context of dysfunctional corticostriatal circuitry.
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Affiliation(s)
| | - George V. Rebec
- Correspondence to: George V. Rebec, PhD, Department of Psychological and Brain Sciences, Program in
Neuroscience, Indiana University, 1101 E. 10th Street, Bloomington, IN 47405-7007, USA. Tel.: +1 812 855 4832;
Fax: +1 812 855 4520; E-mail:
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Abstract
Dystonia is one of the most frequent movement disorders in childhood. It can impede normal motor development and cause significant motor disability. The diagnostic evaluation of childhood dystonia is challenging due to the phenotypic variability and heterogeneous etiologies. Evidence to guide the diagnostic evaluation and treatment is limited. Assessment is primarily directed by clinical history and distinctive examination findings. Neuroimaging is typically necessary to evaluate for acquired or complex inherited dystonias. A trial of levodopa can be both diagnostic and therapeutic in children with dopa-responsive dystonia. However, for the majority of children with early-onset dystonia, treatment is symptomatic with varying efficacy. There is a paucity of therapeutic trials for childhood dystonia and most treatment recommendations are consensus or expert opinion driven. This review summarizes the available evidence and guidelines on the diagnostic evaluation and pharmacological treatment of childhood-onset dystonia and provides practical frameworks to approach both issues based on best evidence.
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Tyebji S, Hannan AJ. Synaptopathic mechanisms of neurodegeneration and dementia: Insights from Huntington's disease. Prog Neurobiol 2017; 153:18-45. [PMID: 28377290 DOI: 10.1016/j.pneurobio.2017.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 03/19/2017] [Accepted: 03/30/2017] [Indexed: 12/20/2022]
Abstract
Dementia encapsulates a set of symptoms that include loss of mental abilities such as memory, problem solving or language, and reduces a person's ability to perform daily activities. Alzheimer's disease is the most common form of dementia, however dementia can also occur in other neurological disorders such as Huntington's disease (HD). Many studies have demonstrated that loss of neuronal cell function manifests pre-symptomatically and thus is a relevant therapeutic target to alleviate symptoms. Synaptopathy, the physiological dysfunction of synapses, is now being approached as the target for many neurological and psychiatric disorders, including HD. HD is an autosomal dominant and progressive degenerative disorder, with clinical manifestations that encompass movement, cognition, mood and behaviour. HD is one of the most common tandem repeat disorders and is caused by a trinucleotide (CAG) repeat expansion, encoding an extended polyglutamine tract in the huntingtin protein. Animal models as well as human studies have provided detailed, although not exhaustive, evidence of synaptic dysfunction in HD. In this review, we discuss the neuropathology of HD and how the changes in synaptic signalling in the diseased brain lead to its symptoms, which include dementia. Here, we review and discuss the mechanisms by which the 'molecular orchestras' and their 'synaptic symphonies' are disrupted in neurodegeneration and dementia, focusing on HD as a model disease. We also explore the therapeutic strategies currently in pre-clinical and clinical testing that are targeted towards improving synaptic function in HD.
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Affiliation(s)
- Shiraz Tyebji
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia; Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia.
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Mason SL, Barker RA. Advancing pharmacotherapy for treating Huntington's disease: a review of the existing literature. Expert Opin Pharmacother 2015; 17:41-52. [PMID: 26536068 DOI: 10.1517/14656566.2016.1109630] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Huntington's disease (HD) is an incurable chronic neurodegenerative disorder that typically presents in mid-life with a range of motor, cognitive and affective problems. Patients are currently managed using a combination of drug treatments and non-pharmacological therapies but at present there is no "gold standard" treatment for any aspect of the disease. AREAS COVERED In this review the empirical evidence supporting the use of drugs commonly used to treat HD was discussed. In particular, we focus on therapeutics that have either reached phase 3 clinical trials or are already in clinical use. EXPERT OPINION The results confirmed that there is a striking lack of evidence to support the efficacy of the drugs currently used in the management of HD. In fact, many drugs are prescribed on the basis of case reports, open label studies, small double blind placebo control trials of limited duration, or personal clinical experience. However of late, the establishment of large international databases, capturing all patients and their clinical details regardless of stage or geographical location has led to an increase in the number of clinical trials conducted on new therapies. Unfortunately, the same is not true for the existing therapies which look set to remain untested for the foreseeable future.
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Affiliation(s)
- Sarah L Mason
- a John Van Geest Centre for Brain Repair , University of Cambridge , Cambridge CB2 0PY , UK
| | - Roger A Barker
- a John Van Geest Centre for Brain Repair , University of Cambridge , Cambridge CB2 0PY , UK.,b Department of Clinical Neuroscience , University of Cambridge , Cambridge CB2 0PY , UK
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Hyperactivation of D1 and A2A receptors contributes to cognitive dysfunction in Huntington's disease. Neurobiol Dis 2015; 74:41-57. [DOI: 10.1016/j.nbd.2014.11.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 10/13/2014] [Accepted: 11/04/2014] [Indexed: 12/22/2022] Open
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Killoran A, Biglan KM. Current therapeutic options for Huntington's disease: good clinical practice versus evidence-based approaches? Mov Disord 2014; 29:1404-13. [PMID: 25164707 DOI: 10.1002/mds.26014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/18/2014] [Accepted: 08/06/2014] [Indexed: 01/17/2023] Open
Abstract
Therapeutic decision-making in Huntington's disease (HD) is often guided by clinical experience, because of the limited empirical evidence available. The only medication for HD that has met the regulatory hurdle for approval is tetrabenazine, indicated for the treatment of chorea. However, its use has limitations, and in the setting of specific contraindications or comorbidities the treatment of choice for chorea is still the multipurpose antipsychotics. For the management of psychiatric disturbances, selective serotonin reuptake inhibitors (SSRIs) and mood stabilizers are often used, although empirical evidence is lacking. Finally, no known effective treatment is available for cognitive dysfunction in HD. We discuss the limited evidence available and current expert opinion on medical treatment of the dominant motor, psychiatric, and cognitive features of HD. This follows a brief introduction on the general principles of HD management and on evidence-based medicine in relation to clinical practice.
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Affiliation(s)
- Annie Killoran
- West Virginia University, Morgantown, West Virginia, USA
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Gupta S, Sharma B. Protective effects of phosphodiesterase-1 (PDE1) and ATP sensitive potassium (KATP) channel modulators against 3-nitropropionic acid induced behavioral and biochemical toxicities in experimental Huntington׳s disease. Eur J Pharmacol 2014; 732:111-22. [DOI: 10.1016/j.ejphar.2014.03.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 03/15/2014] [Accepted: 03/24/2014] [Indexed: 12/16/2022]
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Bernstein AI, Stout KA, Miller GW. The vesicular monoamine transporter 2: an underexplored pharmacological target. Neurochem Int 2014; 73:89-97. [PMID: 24398404 DOI: 10.1016/j.neuint.2013.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 12/21/2022]
Abstract
Active transport of neurotransmitters into synaptic vesicles is required for their subsequent exocytotic release. In the monoamine system, this process is carried out by the vesicular monoamine transporters (VMAT1 and VMAT2). These proteins are responsible for vesicular packaging of dopamine, norepinephrine, serotonin, and histamine. These proteins are essential for proper neuronal function; however, compared to their plasma membrane counterparts, there are few drugs available that target these vesicular proteins. This is partly due to the added complexity of crossing the plasma membrane, but also to the technical difficulty of assaying for vesicular uptake in high throughput. Until recently, reagents to enable high throughput screening for function of these vesicular neurotransmitter transporters have not been available. Fortunately, novel compounds and methods are now making such screening possible; thus, a renewed focus on these transporters as potential targets is timely and necessary.
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Affiliation(s)
- Alison I Bernstein
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Kristen A Stout
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Gary W Miller
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA; Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA; Department of Pharmacology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA.
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Derangula VR, Pilli NR, Nadavala SK, Adireddy V, Inamadugu JK, Ponneri V. Liquid chromatography-tandem mass spectrometric assay for the determination of tetrabenazine and its active metabolites in human plasma: a pharmacokinetic study. Biomed Chromatogr 2013; 27:792-801. [PMID: 23339053 DOI: 10.1002/bmc.2862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/03/2012] [Accepted: 12/03/2012] [Indexed: 01/20/2023]
Abstract
A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of tetrabenazine and its active metabolites α-dihydrotetrabenazine and β-dihydrotetrabenazine in human plasma. Tetrabenazine d7 was used as internal standard (IS). The analytes were extracted from 200 μL aliquots of human plasma via solid-phase extraction using C18 solid-phase extraction cartridges. The reconstituted samples were chromatographed on a Zorbax SB C18 column using a 60:40 (v/v) mixture of acetonitrile and 5 mm ammonium acetate as the mobile phase at a flow rate of 0.8 mL/min. The API-4000 LC-MS/MS in multiple reaction-monitoring mode was used for detection. The calibration curves obtained were linear (r(2) ≥ 0.99) over the concentration range of 0.01-5.03 ng/mL for tetrabenazine and 0.50-100 ng/mL for α-dihydrotetrabenazine and β-dihydrotetrabenazine. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.
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Chen JJ, Ondo WG, Dashtipour K, Swope DM. Tetrabenazine for the Treatment of Hyperkinetic Movement Disorders: A Review of the Literature. Clin Ther 2012; 34:1487-504. [DOI: 10.1016/j.clinthera.2012.06.010] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 11/25/2022]
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