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Boothman I, Clayton LM, McCormack M, Driscoll AM, Stevelink R, Moloney P, Krause R, Kunz WS, Diehl S, O’Brien TJ, Sills GJ, de Haan GJ, Zara F, Koeleman BP, Depondt C, Marson AG, Stefansson H, Stefansson K, Craig J, Johnson MR, Striano P, Lerche H, Furney SJ, Delanty N, Sisodiya SM, Cavalleri GL. Testing for pharmacogenomic predictors of ppRNFL thinning in individuals exposed to vigabatrin. Front Neurosci 2023; 17:1156362. [PMID: 37790589 PMCID: PMC10542409 DOI: 10.3389/fnins.2023.1156362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/25/2023] [Indexed: 10/05/2023] Open
Abstract
Background The anti-seizure medication vigabatrin (VGB) is effective for controlling seizures, especially infantile spasms. However, use is limited by VGB-associated visual field loss (VAVFL). The mechanisms by which VGB causes VAVFL remains unknown. Average peripapillary retinal nerve fibre layer (ppRNFL) thickness correlates with the degree of visual field loss (measured by mean radial degrees). Duration of VGB exposure, maximum daily VGB dose, and male sex are associated with ppRNFL thinning. Here we test the hypothesis that common genetic variation is a predictor of ppRNFL thinning in VGB exposed individuals. Identifying pharmacogenomic predictors of ppRNFL thinning in VGB exposed individuals could potentially enable safe prescribing of VGB and broader use of a highly effective drug. Methods Optical coherence topography (OCT) and GWAS data were processed from VGB-exposed individuals (n = 71) recruited through the EpiPGX Consortium. We conducted quantitative GWAS analyses for the following OCT measurements: (1) average ppRNFL, (2) inferior quadrant, (3) nasal quadrant, (4) superior quadrant, (5) temporal quadrant, (6) inferior nasal sector, (7) nasal inferior sector, (8) superior nasal sector, and (9) nasal superior sector. Using the summary statistics from the GWAS analyses we conducted gene-based testing using VEGAS2. We conducted nine different PRS analyses using the OCT measurements. To determine if VGB-exposed individuals were predisposed to having a thinner RNFL, we calculated their polygenic burden for retinal thickness. PRS alleles for retinal thickness were calculated using published summary statistics from a large-scale GWAS of inner retinal morphology using the OCT images of UK Biobank participants. Results The GWAS analyses did not identify a significant association after correction for multiple testing. Similarly, the gene-based and PRS analyses did not reveal a significant association that survived multiple testing. Conclusion We set out to identify common genetic predictors for VGB induced ppRNFL thinning. Results suggest that large-effect common genetic predictors are unlikely to exist for ppRNFL thinning (as a marker of VAVFL). Sample size was a limitation of this study. However, further recruitment is a challenge as VGB is rarely used today because of this adverse reaction. Rare variants may be predictors of this adverse drug reaction and were not studied here.
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Affiliation(s)
- Isabelle Boothman
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
- The SFI Futureneuro Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
- The SFI Centre for Research Training in Genomics Data Science, Galway, Ireland
| | - Lisa M. Clayton
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- Chalfont Centre for Epilepsy, Bucks, United Kingdom
| | - Mark McCormack
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | | | - Remi Stevelink
- Department of Genetics, University Medical Center Utrecht, Utrecht, Netherlands
| | - Patrick Moloney
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Wolfram S. Kunz
- Division of Neurochemistry, Department of Epileptology, University Bonn Medical Center, Bonn, Germany
| | - Sarah Diehl
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Terence J. O’Brien
- Departments of Neuroscience and Neurology, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, VIC, Australia
| | - Graeme J. Sills
- School of Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gerrit-Jan de Haan
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Federico Zara
- "IRCCS”G. Gaslini" Institute, Genova, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genova, Italy
| | - Bobby P. Koeleman
- Department of Genetics, University Medical Center Utrecht, Utrecht, Netherlands
| | - Chantal Depondt
- Department of Neurology, Hôpital Erasme, Hôpital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Anthony G. Marson
- Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, United Kingdom
| | | | | | - John Craig
- Department of Neurology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Michael R. Johnson
- Division of Brain Sciences, Imperial College Faculty of Medicine, London, United Kingdom
| | - Pasquale Striano
- "IRCCS”G. Gaslini" Institute, Genova, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genova, Italy
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Simon J. Furney
- Genomic Oncology Research Group, Deptartment of Physiology and Medical Physics, Royal College of Surgeons in Ireland (RCSI), Dublin, Ireland
| | - Norman Delanty
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Sanjay M. Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- Chalfont Centre for Epilepsy, Bucks, United Kingdom
| | - Gianpiero L. Cavalleri
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
- The SFI Futureneuro Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
- The SFI Centre for Research Training in Genomics Data Science, Galway, Ireland
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Schein Y, Miller KD, Han Y, Yu Y, de Alba Campomanes AG, Binenbaum G, Oatts JT. Ocular examinations, findings, and toxicity in children taking vigabatrin. J AAPOS 2022; 26:187.e1-187.e6. [PMID: 35817277 PMCID: PMC10947413 DOI: 10.1016/j.jaapos.2022.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/21/2022] [Accepted: 05/01/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND The antiepileptic medication vigabatrin has been associated with ocular toxicity, and close ophthalmic monitoring has been recommended; however, there is no clear consensus regarding the value and feasibility of such monitoring in children. We describe ophthalmic assessments in children in a real-world clinical setting, the incidence of vigabatrin-related ocular toxicity, and the utility of regular screening or ancillary testing in children taking vigabatrin. METHODS The medical records of children taking vigabatrin with one or more ophthalmic assessments at Children's Hospital of Philadelphia or University of California, San Francisco, between May 2010 and May 2021, were reviewed retrospectively. Abnormalities on ophthalmic examination, visual field (VF), electroretinogram (ERG), and optical coherence tomography (OCT) were reviewed and categorized as attributable to vigabatrin, possibly attributable to vigabatrin, or not attributable to vigabatrin. RESULTS A total of 1,281 assessments of 284 children (mean age, 2.09 years) were included. Of these, 283 (99.6%) had funduscopic examination(s), 37 (13.0%) had ERG, 19 (6.7%) had OCT, and 6 (2.1%) had formal VF. Rate of examinations and ERGs per child decreased over the 10-year study period. Two children (0.7%) had definite vigabatrin-related ocular toxicity, both identified on ERG. An additional 4 children (1.4%) had optic atrophy of unclear relation to vigabatrin, categorized as possible toxicity. The remaining 278 children did not have abnormal examination or testing findings attributable to vigabatrin. CONCLUSIONS The incidence of vigabatrin-related ocular toxicity in children was low in our cohort. Ocular and neurologic comorbidities and limited examinations in children make identification of such toxicity challenging and the value of screening is unclear.
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Affiliation(s)
- Yvette Schein
- Division of Ophthalmology, Children's Hospital of Philadelphia, Pennsylvania
| | | | - Ying Han
- Department of Ophthalmology, University of California, San Francisco
| | - Yinxi Yu
- Scheie Eye Institute, Center for Preventive Ophthalmology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | | | - Gil Binenbaum
- Division of Ophthalmology, Children's Hospital of Philadelphia, Pennsylvania
| | - Julius T Oatts
- Department of Ophthalmology, University of California, San Francisco.
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Mohammadian E, Rahimpour E, Foroumadi A, Alizadeh-Sani M, Hasanvand Z, Jouyban A. Derivatization of γ-Amino Butyric Acid Analogues for Their Determination in the Biological Samples and Pharmaceutical Preparations: A Comprehensive Review. Crit Rev Anal Chem 2021; 52:1727-1754. [PMID: 34096806 DOI: 10.1080/10408347.2021.1916733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
γ-Aminobutyric acid (GABA) plays an important role in regulating neuronal excitability. Four structurally related drugs to GABA including pregabalin (PGB), gabapentin (GBP), vigabatrin (VGB), and baclofen are used for the treatment of central nervous system disorders. These drugs are small aliphatic molecules having neither fluorescent nor strong absorbance in the ultraviolet/visible region; therefore, direct determination of these analytes by optical methods is difficult. Additionally, their high boiling point makes gas chromatography impossible. Accordingly, the amine or acid moiety in these drugs is derivatized in order to improve their selectivity and sensitivity during determination in the biological samples. This review focuses on derivatization based methods and their different reactions for determination of PGB, GBP, VGB, and baclofen in the biological samples and pharmaceutical preparations reported between 1980 and 2020. High-performance liquid chromatography methods coupled with different detectors are a commonly used methods for determination of GABA analogs after derivatization. These methods cover 38.89% of all developed methods for determination of GABA analogs.
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Affiliation(s)
- Esmaeil Mohammadian
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Pharmaceutical Analysis Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Elaheh Rahimpour
- Pharmaceutical Analysis Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Foroumadi
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Drug Design and Development Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Alizadeh-Sani
- Student's Scientific Research Center, Department of Food Safety and Hygiene, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Zaman Hasanvand
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Abolghasem Jouyban
- Pharmaceutical Analysis Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Strzelczyk A, Grau J, Bast T, Bertsche A, Bettendorf U, Hahn A, Hartmann H, Hertzberg C, Hornemann F, Immisch I, Jacobs J, Klotz KA, Kluger G, Knake S, Knuf M, Kurlemann G, Marquard K, Mayer T, Meyer S, Muhle H, Müller-Schlüter K, von Podewils F, Rosenow F, Ruf S, Sauter M, Schäfer H, Schlump JU, Schubert-Bast S, Syrbe S, Thiels C, Trollmann R, Wiemer-Kruel A, Wilken B, Zukunft B, Zöllner JP. Prescription patterns of antiseizure drugs in tuberous sclerosis complex (TSC)-associated epilepsy: a multicenter cohort study from Germany and review of the literature. Expert Rev Clin Pharmacol 2021; 14:749-760. [PMID: 33792454 DOI: 10.1080/17512433.2021.1911643] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Seizures are a primary and early disease manifestation of Tuberous Sclerosis Complex (TSC). We aimed to describe the age-stratified patterns of antiseizure drug (ASD) treatments among children, adolescents, and adults with TSC in Germany. Additionally, we reviewed real-world and clinical study evidence regarding ASD utilization in patients with TSC. METHODS We evaluated the pattern of routine ASD use and everolimus prescriptions based on a 2019 multicenter survey of 268 individuals with TSC-associated epilepsy. We contextualized the results with a structured review of real-world and clinical study evidence. RESULTS TSC-associated epilepsy treatment comprises a wide variety of ASDs. In this German sample, the majority of patients were treated with polytherapy, and lamotrigine (34.7%), valproate (32.8%), oxcarbazepine (28.7%), vigabatrin (19.0%), and levetiracetam (17.9%) were identified as the most-commonly used ASDs. In addition, everolimus was used by 32.5% of patients. In adherence to current TSC guidelines, the disease-modifying ASD vigabatrin was widely used in children (58% below the age of 5 years), whereas treatment in adults did not necessarily reflect guideline preference for (partial) GABAergic ASDs. CONCLUSIONS The selection of ASDs for patients with TSC-associated epilepsy follows well-evaluated recommendations, including the guidelines regarding vigabatrin use in children. Several characteristics, such as the comparatively high frequency of valproate use and polytherapy, reflect the severity of TSC-associated epilepsy.
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Affiliation(s)
- Adam Strzelczyk
- Goethe-University Frankfurt, Frankfurt am Main, Germany.,LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt am Main, Germany.,Epilepsy Center Hessen and Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - Janina Grau
- Goethe-University Frankfurt, Frankfurt am Main, Germany.,LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Thomas Bast
- Epilepsy Center Kork, Clinic for Children and Adolescents, Kehl-Kork, Germany
| | - Astrid Bertsche
- Department of Neuropediatrics, University Hospital for Children and Adolescents, Rostock, Germany
| | | | - Andreas Hahn
- Department of Neuropediatrics, Justus-Liebig-University Gießen, Gießen, Germany
| | - Hans Hartmann
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | | | - Frauke Hornemann
- Department of Neuropediatrics, Leipzig University Hospital for Children and Adolescents, Leipzig, Germany
| | - Ilka Immisch
- Epilepsy Center Hessen and Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - Julia Jacobs
- Department of Neuropediatrics and Muscle Disorders, Center for Pediatrics, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg i.Br., Germany.,Department of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kerstin A Klotz
- Department of Neuropediatrics and Muscle Disorders, Center for Pediatrics, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg i.Br., Germany.,Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg i.Br., Germany
| | - Gerhard Kluger
- Clinic for Neuropediatrics and Neurorehabilitation, Epilepsy Center for Children and Adolescents, Schön Klinikum Vogtareuth, Germany.,Research Institute, Rehabilitation, Transition and Palliation, PMU Salzburg, Salzburg, Austria
| | - Susanne Knake
- Epilepsy Center Hessen and Department of Neurology, Philipps-University Marburg, Marburg, Germany
| | - Markus Knuf
- Department of Pediatrics, Helios Dr. Horst Schmidt Kliniken Wiesbaden, Wiesbaden, Germany.,Department of Pediatrics, University Medicine Mainz, Mainz, Germany
| | | | - Klaus Marquard
- Department of Pediatric Neurology, Psychosomatics and Pain Management, Klinikum of Stuttgart, Stuttgart, Germany
| | - Thomas Mayer
- Epilepsy Center Kleinwachau, Dresden-Radeberg, Germany
| | - Sascha Meyer
- Department of Neuropediatrics, University Children´s Hospital of Saarland, Homburg, Germany
| | - Hiltrud Muhle
- Department of Neuropediatrics, Christian-Albrechts-University Kiel & University Hospital Schleswig-Holstein, Campus Kiel, Germany
| | - Karen Müller-Schlüter
- Epilepsy Center for Children, University Hospital Neuruppin, Brandenburg Medical School, Neuruppin, Germany
| | - Felix von Podewils
- Departmental of Neurology, Epilepsy Center, University Medicine Greifswald, Greifswald, Germany
| | - Felix Rosenow
- Goethe-University Frankfurt, Frankfurt am Main, Germany.,LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Susanne Ruf
- Department of Neuropediatrics, University Hospital Tübingen, Tübingen, Germany
| | - Matthias Sauter
- Klinikum Kempten, Klinikverbund Allgäu, Kempten/Allgäu, Germany
| | - Hannah Schäfer
- Division of Nephrology, Medizinische Klinik Und Poliklinik IV, Klinikum der LMU München - Innenstadt, München, Germany.,Department of Nephrology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany
| | - Jan-Ulrich Schlump
- Department of Neuropediatrics, University of Witten/Herdecke, Herdecke, Germany
| | - Susanne Schubert-Bast
- Goethe-University Frankfurt, Frankfurt am Main, Germany.,LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt am Main, Germany.,Department of Neuropediatrics, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Charlotte Thiels
- Department of Neuropediatrics and Social Pediatrics, St. Josef-Hospital, University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum, Bochum, Germany
| | - Regina Trollmann
- Department of Neuropediatrics, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | | | - Bernd Wilken
- Department of Neuropediatrics, Klinikum Kassel, Kassel, Germany
| | - Bianca Zukunft
- Department of Nephrology and Internal Intensive Care, Charité - University Medicine Berlin, Berlin, Germany
| | - Johann Philipp Zöllner
- Goethe-University Frankfurt, Frankfurt am Main, Germany.,LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe-University Frankfurt, Frankfurt am Main, Germany
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Strong AD, Sturdy A, McCourt EA, Braverman RS, Singh JK, Enzenauer RW, Jung JL. Clinical Utility of Electroretinograms for Evaluating Vigabatrin Toxicity in Children. J Pediatr Ophthalmol Strabismus 2021; 58:174-179. [PMID: 34039156 DOI: 10.3928/01913913-20210111-03] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine changes in the clinical treatment of pediatric patients taking vigabatrin for seizure control in response to results of electroretinogram (ERG) performed for retinal toxicity screening. METHODS The authors retrospectively reviewed the medical records of patients who received ERGs at Children's Hospital of Colorado from 2009 to 2012. Age, indication for ERG, ERG data, and clinical management of vigabatrin were extracted from the records. ERGs were interpreted according to LKC Technologies normative values. A physician trained in ERG analysis interpreted each ERG. RESULTS One hundred seventy ERGs were performed during the study period, and 147 ERGs were available for analysis. Every patient received general anesthesia for the procedure. Thirty-three ERGs were performed in 29 patients specifically as screening for retinal toxicity due to vigabatrin use, and 30 were available for analysis. Within this cohort, only 2 ERGs were normal (6.6%), and 28 were abnormal (93.3%). In patients who received abnormal results, 1 patient discontinued vigabatrin in response to the screening. CONCLUSIONS In this study cohort, clinical management generally did not change in response to an abnormal screening result. Given the need for general anesthesia in the pediatric population receiving ERG testing, and minimal change in clinical decision-making in the face of abnormal results, ERG screening for retinal toxicity due to vigabatrin in the pediatric cohort should be reconsidered. [J Pediatr Ophthalmol Strabismus. 2021;58(3):174-179.].
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Walsh SJ, Chen RJ, Ershad M, Krueger JA. The Toxicity of Newer and Lesser-Known Anticonvulsant Drugs. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2020. [DOI: 10.1007/s40138-020-00220-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Objective Derivation of the Morphology and Staging of Visual Field Loss Associated with Long-Term Vigabatrin Therapy. CNS Drugs 2019; 33:817-829. [PMID: 31250314 DOI: 10.1007/s40263-019-00634-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The morphology and between-eye symmetry of the visual field loss associated with the antiepileptic drug vigabatrin (VAVFL) has received little attention. OBJECTIVE Our objective was to model the appearance and ensuing staging of VAVFL derived with the European Medicines Agency-approved perimetric protocol. METHODS This was a retrospective, cross-sectional, observational study that identified 123 adults who had received vigabatrin for refractory seizures and who had no evidence of co-existing retino-geniculo-cortical visual pathway abnormality. A further 38 adults with refractory seizures and identical inclusion criteria but no exposure to vigabatrin acted as controls. For each group, the median outcome at each stimulus location in each eye (of absolute loss, relative loss or Pattern Deviation probability level, as appropriate) was derived for each successive ten pairs of fields, ranked for severity. Between-eye symmetry was quantified by an index that accounted for severity of loss and that was referenced to the likelihood of the occurrence of symmetry due to chance. RESULTS The modelled VAVFL was bilateral and highly symmetrical and was described by six stages that were all independent of the extent of vigabatrin exposure. The loss originated in the extreme temporal periphery and encroached centripetally along all meridians towards fixation. The initial appearance within the central field (Stage 2) occurred inferior-nasally. Subsequent stages exhibited increasing loss, which was greater nasally than temporally. Stage 6 described concentric loss extending to approximately 15° eccentricity from fixation. CONCLUSION The model exhibited a consistent pattern of VAVFL. The staging of the loss could assist the risk:benefit analysis of vigabatrin for the treatment of epilepsy.
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Abstract
INTRODUCTION Epilepsy is a serious chronic neurological disorder manifested by an enduring symptomatic predisposition to seizures. Newly diagnosed individuals face increased morbidity, mortality, and socioeconomic costs. Anti-epileptic drug therapy is the treatment usually prescribed, which has efficacy in seizure control and mitigating long-term mortality. AREAS COVERED Safety of anti-epileptic drug therapy in adults with a focus in newly diagnosed patients. Areas covered include the most commonly experienced adverse drug effects, as well as those with the highest impacts on drug tolerability, quality of life, morbidity and mortality. Evidence was also reviewed to identify clinical strategies to improve the safety of anti-epileptic drug therapy. EXPERT OPINION Anti-epileptic drugs (AEDs) are mostly effective and well tolerated. However, a lack of standardised reporting of adverse drug effects in trials and in clinical practice provides an obstacle for evaluation of which adverse drug effects need to be prioritised in management. Improvement in the reporting of cognitive and other effects, as well as improved precision medicine and pharmacogenomics to target the incidence of high-mortality idiosyncratic reactions, will help to reduce the harm of AEDs in people newly diagnosed with epilepsy.
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Affiliation(s)
- Sameer Sharma
- a Department of Neuroscience , Central Clinical School, Monash University , Melbourne , Australia
| | - Patrick Kwan
- a Department of Neuroscience , Central Clinical School, Monash University , Melbourne , Australia.,b Department of Medicine , Royal Melbourne Hospital, The University of Melbourne , Melbourne , Australia.,c School of Public Health and Preventive Medicine , Monash University , Melbourne , Australia
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Hamed SA. Ocular dysfunctions and toxicities induced by antiepileptic medications: Types, pathogenic mechanisms, and treatment strategies. Expert Rev Clin Pharmacol 2019; 12:309-328. [PMID: 30840840 DOI: 10.1080/17512433.2019.1591274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Ocular dysfunctions and toxicities induced by antiepileptic drugs (AEDs) are rarely reviewed and not frequently received attention by treating physicians compared to other adverse effects (e.g. endocrinologic, cognitive and metabolic). However, some are frequent and progressive even in therapeutic concentrations or result in permanent blindness. Although some adverse effects are non-specific, others are related to the specific pharmacodynamics of the drug. Areas covered: This review was written after detailed search in PubMed, EMBASE, ISI web, SciELO, Scopus, and Cochrane Central Register databases (from 1970 to 2019). It summarized the reported ophthalmologic adverse effects of the currently available AEDs; their risks and possible pathogenic mechanisms. They include ocular motility dysfunctions, retinopathy, maculopathy, glaucoma, myopia, optic neuropathy, and impaired retinal vascular autoregulation. In general, ophthalmo-neuro- or retino-toxic adverse effects of AEDs are classified as type A (dose-dependent), type B (host-dependent or idiosyncratic) or type C which is due to the cumulative effect from long-term use. Expert opinion: Ocular adverse effects of AEDs are rarely reviewed although some are frequent or may result in permanent blindness. Increasing knowledge of their incidence and improving understanding of their risks and pathogenic mechanisms are crucial for monitoring, prevention, and management of patients' at risk.
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Affiliation(s)
- Sherifa A Hamed
- a Department of Neurology and Psychiatry , Assiut University Hospital , Assiut , Egypt
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10
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Hand-held, dilation-free, electroretinography in children under 3 years of age treated with vigabatrin. Doc Ophthalmol 2019; 138:195-203. [DOI: 10.1007/s10633-019-09684-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 02/22/2019] [Indexed: 10/27/2022]
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Wild JM, Aljarudi S, Smith PEM, Knupp C. The Topographical Relationship between Visual Field Loss and Peripapillary Retinal Nerve Fibre Layer Thinning Arising from Long-Term Exposure to Vigabatrin. CNS Drugs 2019; 33:161-173. [PMID: 30637668 DOI: 10.1007/s40263-018-0583-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The antiepileptic drug vigabatrin is associated with characteristic visual field loss (VAVFL) and thinning of the peripapillary retinal nerve fibre layer (PPRNFL); however, the relationship is equivocal. OBJECTIVE The aim of this study was to determine the function-structure relationship associated with long-term exposure to vigabatrin, thereby improving the risk/benefit analysis of the drug. METHODS A cross-sectional observational design identified 40 adults who had received long-term vigabatrin for refractory seizures, who had no evidence of co-existing retino-geniculo-cortical visual pathway abnormality, and who had undergone a standardized protocol of perimetry and of optical coherence tomography (OCT) of the PPRNFL. Vigabatrin toxicity was defined as the presence of VAVFL. The function-structure relationship for the superior and inferior retinal quadrants was evaluated by two established models applicable to other optic neuropathies. RESULTS The function-structure relationship for each model was consistent with an optic neuropathy. PPRNFL thinning, expressed in micrometres, asymptoted at an equivalent visual field loss of worse than approximately - 10.0 dB, thereby preventing assessment of more substantial thinning. Transformation of the outcomes to retinal ganglion cell soma and axon estimates, respectively, resulted in a linear relationship. CONCLUSIONS Functional and structural abnormality is strongly related in individuals with vigabatrin toxicity and no evidence of visual pathway comorbidity, thereby implicating retinal ganglion cell dysfunction. OCT affords a limited measurement range compared with perimetry: severity cannot be directly assessed when the PPRNFL quadrant thickness is less than approximately 65 µm, depending on the tomographer. This limitation can be overcome by transformation of thickness to remaining axons, an outcome requiring input from perimetry.
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Affiliation(s)
- John M Wild
- College of Biomedical Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK.
| | - Saleh Aljarudi
- College of Biomedical Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK.,Dhahran Eye Specialist Hospital, Dhahran, 7500, Saudi Arabia
| | - Philip E M Smith
- Alan Richens Unit, Welsh Epilepsy Centre, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK
| | - Carlo Knupp
- College of Biomedical Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
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Hui A, Liu D, Wong K, Man B, Leung T, Lam P, Lam D. Vigabatrin-Induced Visual Dysfunction in Chinese Patients with Refractory Epilepsy. Eur J Ophthalmol 2018; 18:624-7. [PMID: 18609486 DOI: 10.1177/112067210801800421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- A.C.F. Hui
- Division of Neurology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - D.T.L. Liu
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - K.K. Wong
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - B.L. Man
- Division of Neurology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - T. Leung
- Division of Neurology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - P.T.H. Lam
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
| | - D.S.C. Lam
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong - PR China
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VIGABATRIN TOXICITY IN INFANCY IS ASSOCIATED WITH RETINAL DEFECT IN ADOLESCENCE: A Prospective Observational Study. Retina 2017; 37:858-866. [PMID: 27552291 DOI: 10.1097/iae.0000000000001246] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose was to determine whether vigabatrin (VGB) (Sabril)-attributed retinal toxicity defined by electroretinogram in early childhood is associated with visual system defect in adolescents after discontinuation of VGB. METHODS This prospective cross-sectional study included 24 children previously treated with VGB and monitored in early childhood by electroretinogram for VGB-attributed retinal defects. Ten had been diagnosed with VGB-attributed retinal defect (Group I) and 14 had no VGB-attributed retinal defect (Group II). Outcome measures were extent of monocular visual fields using Goldmann kinetic perimetry and RNFL thickness at the optic nerve head, using optical coherence tomography. RESULTS Of those able to complete testing (6 eyes Group I and 16 eyes Group II), Goldmann results revealed results of visual field loss in Group I and not in Group II. The optical coherence tomography results demonstrated attenuation of the RNFL in all 6 eyes of Group I participants and in only 1 eye of 10 Group II participants. Optical coherence tomography data were nonoverlapping between Group 1 and Group II eyes. CONCLUSION The VGB-attributed retinal toxicity identified by means of electroretinogram in infancy was associated with visual field loss and RNFL attenuation of the retinal nerve when tested in adolescence.
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Dettoraki M, Moschos MM. The Role of Multifocal Electroretinography in the Assessment of Drug-Induced Retinopathy: A Review of the Literature. Ophthalmic Res 2016; 56:169-177. [PMID: 27351191 DOI: 10.1159/000446321] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/19/2016] [Indexed: 11/19/2022]
Abstract
Multifocal electroretinography (mfERG) is an objective, noninvasive examination for the assessment of visual function. It enables the stimulation of multiple retinal areas simultaneously and recording of each response independently, providing a topographic measure of retinal electrophysiological activity in the central 40-50° of the retina. A clinical application of mfERG represents the assessment of retinal toxicity associated with systemic medications. Drug-induced retinopathy represents a disease that, although not common, requires early recognition: if not detected early, it may progress and cause irreversible retinal dysfunction with subsequent visual impairment. This review aims to evaluate the use of mfERG in the assessment of retinal dysfunction associated with various systemic pharmacological agents based on the currently available literature. The most commonly recognized systemic medications affecting retinal function are included, such as chloroquine and hydroxychloroquine, vigabatrin, deferoxamine, ethambutol, interferon-α, tamoxifen, digoxin, sildenafil, canthaxanthin, amiodarone and nefazodone. The role of mfERG in the early diagnosis of retinal toxicity and the evaluation of disease severity is reviewed, as well as its clinical value in monitoring disease progression or recovery after drug cessation.
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Affiliation(s)
- Maria Dettoraki
- Department of Ophthalmology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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15
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Hébert-Lalonde N, Carmant L, Major P, Roy MS, Lassonde M, Saint-Amour D. Electrophysiological Evidences of Visual Field Alterations in Children Exposed to Vigabatrin Early in Life. Pediatr Neurol 2016; 59:47-53. [PMID: 27105764 DOI: 10.1016/j.pediatrneurol.2016.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 03/04/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND We assessed central and peripheral visual field processing in children with epilepsy who were exposed to vigabatrin during infancy. METHODS Steady-state visual evoked potentials and pattern electroretinograms to field-specific radial checkerboards flickering at two cycle frequencies (7.5 and 6 Hz for central and peripheral stimulations, respectively) were recorded from Oz and at the eye in seven school-age children (10.1 ± 3.5 years) exposed to vigabatrin early in life, compared with children early exposed to other antiepileptic drugs (n = 9) and healthy children (n = 8). The stimulation was made of two concentric circles (0 to 5 and 30 to 60 degrees of angle) and presented at four contrast levels (96%, 64%, 32%, and 16%). RESULTS Ocular responses were similar in all groups for central but not for the peripheral stimulations, which were significantly lower in the vigabatrin-exposed group at high contrast level. This peripheral retinal response was negatively correlated to vigabatrin exposure duration. Cortical responses to central stimulations, including contrast response functions in the children with epilepsy in both groups, were lower than those in normally developing children. CONCLUSIONS Alteration of ocular processing was found only in the vigabatrin-exposed children. Central cortical processing, however, was impaired in both epileptic groups, with more pronounced effects in vigabatrin-exposed children. Our study suggests that asymptomatic long-term visual toxicity may still be present at school age, even several years after discontinuation of drug therapy.
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Affiliation(s)
- Noémie Hébert-Lalonde
- Department of Psychology, Université de Montréal, Montreal, Quebec, Canada; Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Lionel Carmant
- Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Division of Neurology, Department of Pediatrics, Sainte-Justine Hospital, Université de Montréal, Montreal, Quebec, Canada
| | - Philippe Major
- Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Division of Neurology, Department of Pediatrics, Sainte-Justine Hospital, Université de Montréal, Montreal, Quebec, Canada
| | | | - Maryse Lassonde
- Department of Psychology, Université de Montréal, Montreal, Quebec, Canada; Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Dave Saint-Amour
- Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Department of Ophtalmology, Université de Montréal, Montreal, Quebec, Canada; Department of Psychology, Université du Québec à Montréal, Montreal, Quebec, Canada.
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16
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Kotagal P. Limiting Retinal Toxicity of Vigabatrin in Children With Infantile Spasms. Epilepsy Curr 2015; 15:327-9. [PMID: 26633952 PMCID: PMC4657771 DOI: 10.5698/1535-7511-15.6.327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Moreno MC, Giagante B, Saidon P, Kochen S, Benozzi J, Rosenstein RE. Visual Defects Associated with Vigabatrin: A Study of Epileptic Argentine Patients. Can J Neurol Sci 2014; 32:459-64. [PMID: 16408575 DOI: 10.1017/s0317167100004443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
ABSTRACT:Objective:The aim of the present study was to assess visual alterations in a population of Argentine patients treated with the antiepileptic drug vigabatrin.Methods:Twenty patients receiving vigabatrin and 15 patients receiving carbamazepine were examined with automated perimetry using a Humphrey 120-point full screening strategy. In addition, scotopic flash electroretinograms were performed.Results:Of 20 patients treated with vigabatrin, two were unable to cooperate with testing. Of the remaining 18 patients, all but two showed at least one non-detected point inside the central 40° of the visual field of each eye. Of the 15 carbamazepine-treated patients, three were unable to perform the study. None of the remaining 12 patients showed visual field defects. Both a- and b-wave amplitudes of the scotopic electroretinogram were significantly reduced in 12 patients receiving vigabatrin.Conclusions:Visual field defects among patients on vigabatrin therapy may occur with a higher frequency than previously recognized. The Humphrey 120-points full field screening test and electroretinography are useful tools to assess the visual dysfunction associated with vigabatrin.
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Affiliation(s)
- María Cecilia Moreno
- Laboratory of Retinal Neurochemistry, Epilepsy Center, Ramos Mejia Hospital, School of Medicine, University of Buenos Aires, Paraguay 2155, 50 P, Buenos Aires, Argentina
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18
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Abstract
Several new antiepileptic drugs (AED's) have been approved by the FDA in the last 2 decades. The newer AED's score over the older ones, in terms of improved tolerability, safety, improved pharmacokinetics and lower drug-drug interactions. However, efficacy may not be significantly higher. This article reviews the newer antiepileptics approved in the pediatric age group and the evidence for or against their clinical use.
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Cooke Bailey JN, Yaspan BL, Pasquale LR, Hauser MA, Kang JH, Loomis SJ, Brilliant M, Budenz DL, Christen WG, Fingert J, Gaasterland D, Gaasterland T, Kraft P, Lee RK, Lichter PR, Liu Y, McCarty CA, Moroi SE, Richards JE, Realini T, Schuman JS, Scott WK, Singh K, Sit AJ, Vollrath D, Wollstein G, Zack DJ, Zhang K, Pericak-Vance MA, Allingham RR, Weinreb RN, Haines JL, Wiggs JL. Hypothesis-independent pathway analysis implicates GABA and acetyl-CoA metabolism in primary open-angle glaucoma and normal-pressure glaucoma. Hum Genet 2014; 133:1319-30. [PMID: 25037249 PMCID: PMC4273559 DOI: 10.1007/s00439-014-1468-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/08/2014] [Indexed: 12/15/2022]
Abstract
Primary open-angle glaucoma (POAG) is a leading cause of blindness worldwide. Using genome-wide association single-nucleotide polymorphism data from the Glaucoma Genes and Environment study and National Eye Institute Glaucoma Human Genetics Collaboration comprising 3,108 cases and 3,430 controls, we assessed biologic pathways as annotated in the KEGG database for association with risk of POAG. After correction for genic overlap among pathways, we found 4 pathways, butanoate metabolism (hsa00650), hematopoietic cell lineage (hsa04640), lysine degradation (hsa00310) and basal transcription factors (hsa03022) related to POAG with permuted p < 0.001. In addition, the human leukocyte antigen (HLA) gene family was significantly associated with POAG (p < 0.001). In the POAG subset with normal-pressure glaucoma (NPG), the butanoate metabolism pathway was also significantly associated (p < 0.001) as well as the MAPK and Hedgehog signaling pathways (hsa04010 and hsa04340), glycosaminoglycan biosynthesis-heparan sulfate pathway (hsa00534) and the phenylalanine, tyrosine and tryptophan biosynthesis pathway (hsa0400). The butanoate metabolism pathway overall, and specifically the aspects of the pathway that contribute to GABA and acetyl-CoA metabolism, was the only pathway significantly associated with both POAG and NPG. Collectively these results implicate GABA and acetyl-CoA metabolism in glaucoma pathogenesis, and suggest new potential therapeutic targets.
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Affiliation(s)
| | - Brian L. Yaspan
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN, USA
| | - Louis R. Pasquale
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael A. Hauser
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Jae H. Kang
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Stephanie J. Loomis
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Murray Brilliant
- Center for Human Genetics, Marshfield Clinic Research Foundation, Marshfield, WI, USA
| | - Donald L. Budenz
- Department of Ophthalmology, University of North Carolina, Chapel Hill, NC, USA
| | | | - John Fingert
- Department of Ophthalmology, College of Medicine, University of Iowa, Iowa City, IO, USA
- Department of A natomy/Cell Biology, College of Medicine, University of Iowa, Iowa City, IO, USA
| | | | - Terry Gaasterland
- Scripps Genome Center, University of California at San Diego, San Diego, CA, USA
| | - Peter Kraft
- Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA
| | - Richard K. Lee
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Paul R. Lichter
- Department of Ophthalmology and V isual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Yutao Liu
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | | | - Sayoko E. Moroi
- Department of Ophthalmology and V isual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Julia E. Richards
- Department of Ophthalmology and V isual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Tony Realini
- Department of Ophthalmology, WVU Eye Institute, Morgantown, WV, USA
| | - Joel S. Schuman
- Department of Ophthalmology, UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - William K. Scott
- Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Kuldev Singh
- Department of Ophthalmology, Stanford University, Palo Alto, CA, USA
| | - Arthur J. Sit
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
| | | | - Gadi Wollstein
- Department of Ophthalmology, UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA, USA
| | - Donald J. Zack
- Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, MD, USA
| | - Kang Zhang
- Department of Ophthalmology, Hamilton Eye Center, University of California, San Diego, CA, USA
| | | | - R. Rand Allingham
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Robert N. Weinreb
- Department of Ophthalmology, Hamilton Eye Center, University of California, San Diego, CA, USA
| | - Jonathan L. Haines
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN, USA
| | - Janey L. Wiggs
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
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Froger N, Moutsimilli L, Cadetti L, Jammoul F, Wang QP, Fan Y, Gaucher D, Rosolen SG, Neveux N, Cynober L, Sahel JA, Picaud S. Taurine: the comeback of a neutraceutical in the prevention of retinal degenerations. Prog Retin Eye Res 2014; 41:44-63. [PMID: 24721186 DOI: 10.1016/j.preteyeres.2014.03.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 12/21/2022]
Abstract
Taurine is the most abundant amino acid in the retina. In the 1970s, it was thought to be involved in retinal diseases with photoreceptor degeneration, because cats on a taurine-free diet presented photoreceptor loss. However, with the exception of its introduction into baby milk and parenteral nutrition, taurine has not yet been incorporated into any commercial treatment with the aim of slowing photoreceptor degeneration. Our recent discovery that taurine depletion is involved in the retinal toxicity of the antiepileptic drug vigabatrin has returned taurine to the limelight in the field of neuroprotection. However, although the retinal toxicity of vigabatrin principally involves a deleterious effect on photoreceptors, retinal ganglion cells (RGCs) are also affected. These findings led us to investigate the possible role of taurine depletion in retinal diseases with RGC degeneration, such as glaucoma and diabetic retinopathy. The major antioxidant properties of taurine may influence disease processes. In addition, the efficacy of taurine is dependent on its uptake into retinal cells, microvascular endothelial cells and the retinal pigment epithelium. Disturbances of retinal vascular perfusion in these retinal diseases may therefore affect the retinal uptake of taurine, resulting in local depletion. The low plasma taurine concentrations observed in diabetic patients may further enhance such local decreases in taurine concentration. We here review the evidence for a role of taurine in retinal ganglion cell survival and studies suggesting that this compound may be involved in the pathophysiology of glaucoma or diabetic retinopathy. Along with other antioxidant molecules, taurine should therefore be seriously reconsidered as a potential treatment for such retinal diseases.
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Affiliation(s)
- Nicolas Froger
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France.
| | - Larissa Moutsimilli
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - Lucia Cadetti
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - Firas Jammoul
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - Qing-Ping Wang
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - Yichao Fan
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - David Gaucher
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; Nouvel hôpital civil, hôpitaux universitaires de Strasbourg and Laboratoire de Bactériologie (EA-7290), Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, France
| | - Serge G Rosolen
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France
| | - Nathalie Neveux
- Department of Nutrition, Faculty of Pharmacy, Paris Descartes University, Paris, France; Clinical Chemistry, Hôtel-Dieu-Cochin Hospitals, AP-HP, Paris, France
| | - Luc Cynober
- Department of Nutrition, Faculty of Pharmacy, Paris Descartes University, Paris, France; Clinical Chemistry, Hôtel-Dieu-Cochin Hospitals, AP-HP, Paris, France
| | - José-Alain Sahel
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; Institute of Ophthalmology, University College of London, UK; Fondation Ophtalmologique Adolphe de Rothschild, Paris, France; French Academy of Sciences, Paris, France
| | - Serge Picaud
- INSERM, U968, Institut de la Vision, Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S 968, Institut de la Vision, Paris, France; CNRS, UMR 7210, Institut de la Vision, Paris, France; Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.
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Kjellström U, Andréasson S, Ponjavic V. Attenuation of the retinal nerve fibre layer and reduced retinal function assessed by optical coherence tomography and full-field electroretinography in patients exposed to vigabatrin medication. Acta Ophthalmol 2014; 92:149-57. [PMID: 23387307 DOI: 10.1111/aos.12030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To investigate the clinical value of assessment of peripapillary retinal nerve fibre layer (RNFL) thickness with OCT in addition to the evaluation of retinal function measured by full-field electroretinography (ff-ERG) in patients with suspected vigabatrin (VGB)-attributed visual field defects. METHODS Visual fields from adult patients in our clinical follow-up program for VGB medication were analysed. Twelve patients with suspected VGB-attributed visual field defects were selected for the study. They were re-examined with computerized kinetic perimetry, ff-ERG and OCT (2D circle scan). RESULTS Constricted visual fields were found in all patients. Comparative analysis of ff-ERG parameters showed reduced b-wave amplitudes for the isolated and the combined rod and cone responses (p < 0.0001). The a-wave, reflecting photoreceptor activity, was reduced (p = 0.001), as well as the summed amplitude of oscillatory potentials (p = 0.029), corresponding to inner retinal function. OCT measurements demonstrated attenuation of the RNFL in nine of 12 patients, most frequently superiorly and/or inferiorly. No temporal attenuation was found. Significant positive correlations were found between the total averaged RNFL thickness, superior and inferior RNFL thickness and reduced ff-ERG parameters. Positive correlations were also found between RNFL thickness and isopter areas. CONCLUSION OCT measurements can detect attenuation of the RNFL in patients exposed to VGB medication. RNFL thickness correlates with reduced ff-ERG parameters and isopter areas of constricted visual fields, indicating that VGB is retino-toxic on several levels, from photoreceptors to ganglion cells. The study also supports previous studies, suggesting that OCT measurement of the RNFL thickness may be of clinical value in monitoring patients on vigabatrin therapy.
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Guerrini R, Rosati A, Bradshaw K, Giorgi L. Adjunctive zonisamide therapy in the long-term treatment of children with partial epilepsy: results of an open-label extension study of a phase III, randomized, double-blind, placebo-controlled trial. Epilepsia 2014; 55:568-78. [PMID: 24621319 DOI: 10.1111/epi.12548] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the safety/tolerability and efficacy of long-term adjunctive zonisamide and its impact on growth and development in children (6-18 years) with partial epilepsy. METHODS Open-label extension of a phase III, placebo-controlled trial. Started with double-blind transition period (2-11 weeks), during which patients on zonisamide continued at the same dose and those on placebo switched to zonisamide 1 mg/kg/day, up-titrated to 8 mg/kg/day (maximum 500 mg/day). During the subsequent open-label period (45-57 weeks), zonisamide dosing could be adjusted according to tolerability/response. Safety assessments included treatment-emergent adverse events (TEAEs), clinical laboratory parameters, and vital signs. Efficacy assessments included responder rate (primary assessment) and seizure freedom rate during the open-label period. Growth and development assessments comprised Tanner stages, hand x-rays, Child Behavior Checklist (CBCL 6/18), School Performance questionnaire, Physician and Parent/Guardian Global Impression of Change, and Controlled Oral Word Association Test (COWAT). RESULTS One hundred forty-four children entered the study; 99 (68.8%) of 144 children completed it, and 108 (75.0%) of 144 received zonisamide for ≥1 year. TEAEs occurred in 39 (27.1%) of 144 patients. There were low incidences of serious TEAEs (2.1%) and TEAEs leading to discontinuation (2.8%). Bicarbonate level decreases >3.5 mm occurred in 64 patients (44.4%), and 24 patients (16.7%) had a weight decrease of ≥10% from baseline. During the open-label period, 81 (56.3%) of 144 patients were responders and 16 (11.1%) of 144 achieved seizure freedom. Tanner staging and skeletal development were as expected for the study population. Changes were minimal for CBCL 6/18 and School Performance scores. Most patients were "much improved"/"very much improved" on Physician (73.8%) and Parent/Guardian (75.4%) Global Impressions of Change. Median changes in COWAT Category and Letter Fluency scores were 2.0 and 0.5, respectively. SIGNIFICANCE Adjunctive zonisamide was well tolerated and efficacious over a period of at least 1 year in children with partial epilepsy, with no unexpected safety concerns and no consistent detrimental effects on growth and development. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
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Affiliation(s)
- Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, Department of Neuroscience, Pharmacology and Child Health, Children's Hospital Anna Meyer, University of Florence, Florence, Italy
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Canpolat M, Per H, Gumus H, Yikilmaz A, Unal E, Patiroglu T, Cinar L, Kurtsoy A, Kumandas S. Rapamycin has a beneficial effect on controlling epilepsy in children with tuberous sclerosis complex: results of 7 children from a cohort of 86. Childs Nerv Syst 2014; 30:227-40. [PMID: 23743820 DOI: 10.1007/s00381-013-2185-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 05/23/2013] [Indexed: 01/03/2023]
Abstract
PURPOSE Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the formation of hamartomas in various organ systems. We would like share our experience from 86 patients and the results of rapamycin treatment in seven children with TSC. METHODS Eighty-six children with TSC were enrolled into this retrospective study. The clinical features of seven children treated with oral rapamycin were presented in detail. RESULTS The most common complaint of administration was convulsion in 77 children (89.5%). Hypopigmented skin lesions, adenoma sebaceum, resistant epilepsy, intracardiac mass, renal angiomyolipomas, and West syndrome were detected (n = 83, 96.5%; n = 47, 54.7%; n = 36, 41.9%; n = 27, 31.4%; n = 18, 20.9%; and n = 13, 15.1%, respectively). Subependymal nodules were the most frequent finding in cranial imaging followed by cortical tubers and subependymal giant cell astrocytomas (n = 75, 87.2%; n = 71, 82.6%; and n = 8, 9.3%, respectively). Of the seven patients treated with rapamycin, the lesions of six children with facial adenoma sebaceum showed regression in various degrees. The frequency of convulsions decreased in five patients with resistant epilepsy within the first 6 months of the treatment, and complete control of convulsion for all patients was achieved in the second 6 months. CONCLUSION This is the first study that showed that rapamycin is an effective agent for controlling epilepsy without any significant side effect in children with TSC. Rapamycin seems to be effective after 6 months of therapy, and we recommend tapering the dosage after successful management of epilepsy.
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Affiliation(s)
- Mehmet Canpolat
- Department of Pediatrics, Division of Pediatric Neurology, Faculty of Medicine, Erciyes University, 38039, Kayseri, Turkey
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Curatolo P, D’Argenzio L, Cerminara C, Bombardieri R. Management of epilepsy in tuberous sclerosis complex. Expert Rev Neurother 2014; 8:457-67. [DOI: 10.1586/14737175.8.3.457] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wild JM, Fone DL, Aljarudi S, Lawthom C, Smith PEM, Newcombe RG, Lewis GD. Modelling the risk of visual field loss arising from long-term exposure to the antiepileptic drug vigabatrin: a cross-sectional approach. CNS Drugs 2013; 27:841-9. [PMID: 23990316 DOI: 10.1007/s40263-013-0100-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The antiepileptic drug vigabatrin has been used widely since 1989, but has only been approved for use in the US since 2009. The risk:benefit of vigabatrin is generally predicated upon an assumed frequency of associated visual field loss (VAVFL) of approximately 31 %. This estimate is based upon relatively short-term usage (up to 4-5 years) and it is essential to determine whether the frequency of VAVFL increases with longer-term usage. OBJECTIVE The aim of this study was to model, from cross-sectional evidence, over greater ranges of treatment duration and cumulative dose than previously evaluated, the risk (frequency) of VAVFL with increasing exposure to vigabatrin. STUDY DESIGN AND SETTING This was a retrospective cohort study undertaken in a regional hospital epilepsy clinic. PATIENTS The cohort comprised 147 consecutive patients treated with vigabatrin for refractory complex partial (focal) seizures, who had all undergone ophthalmological examination and who had undertaken perimetry, reliably, according to a standard and robust protocol. The visual field plots were evaluated masked to treatment duration and dose. MAIN OUTCOME MEASURE The risk (frequency) of VAVFL with increasing exposure to vigabatrin was modelled, from the cross-sectional evidence, by standard and plateau logistic regression. RESULTS The cohort comprised 80 females and 67 males (mean age 40.3 years, standard deviation 13.7). The median duration of vigabatrin exposure was 7.9 years (interquartile range 3.6-11.0, range 0.2-16.1 years); 46 patients (31 %) had received vigabatrin for over 10 years. Eighty-seven patients (59 %) exhibited VAVFL; the proportion with VAVFL was higher in males (66 %) than females (54 %). The plateau model for duration and for cumulative dose exhibited a better fit than the standard model (both p < 0.001). The modelled frequency of VAVFL increased with increasing exposure up to approximately 6 years duration and 5 kg cumulative dose, and plateaued at approximately 76 % (95 % CI 67-85) and 79 % (95 % CI 70-87), respectively. Severity of VAVFL, classified in terms of the visual field index Mean Deviation, was not significantly associated with either duration or cumulative dose of therapy. CONCLUSION Clinicians and patients, in enabling informed choice, should be alert to the possible substantial increased risk:benefit for VAVFL with increasing long-term exposure to vigabatrin and the ensuing increased cost:benefit resulting from the necessary additional visual assessments.
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Affiliation(s)
- John M Wild
- Cardiff Centre for Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Maindy Road, Cardiff, Wales, CF24 4HQ, UK,
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Evolution of visual field loss over ten years in individuals taking vigabatrin. Epilepsy Res 2013; 105:262-71. [DOI: 10.1016/j.eplepsyres.2013.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 02/04/2013] [Accepted: 02/27/2013] [Indexed: 11/19/2022]
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Heim MK, Gidal BE. Vigabatrin-associated retinal damage: potential biochemical mechanisms. Acta Neurol Scand 2012; 126:219-28. [PMID: 22632110 DOI: 10.1111/j.1600-0404.2012.01684.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2012] [Indexed: 12/13/2022]
Abstract
Vigabatrin (VGB), an irreversible inhibitor of gamma-aminobutyric acid (GABA) transaminase, is approved as adjunct treatment of refractory partial seizures as well as infantile spasms. Although VGB has been proven to be effective, its use is limited by the risk of retinopathy and associated peripheral visual field defects. This review describes and analyzes current literature related to potential pathophysiologic mechanisms underlying VGB-mediated cellular toxicity. Animal data suggest that GABA mediates neural excitotoxicity. The amino acid taurine is concentrated in retinal cells, and deficiency of this amino acid may be involved in VGB-mediated retinal degeneration and possible phototoxicity.
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Affiliation(s)
- M. K. Heim
- School of Pharmacy; University of Wisconsin - Madison; Madison; WI; USA
| | - B. E. Gidal
- School of Pharmacy & Department of Neurology; University of Wisconsin - Madison; Madison; WI; USA
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Abstract
PURPOSE OF REVIEW Various medications can modify the physiology of retinal and cochlear neurons and lead to major, sometime permanent, sensory loss. A better knowledge of pathogenic mechanisms and the establishment of relevant monitoring protocols are necessary to prevent permanent sensory impairment. In this article, we review main systemic medications associated with direct neuronal toxicity on the retina and cochlea, their putative pathogenic mechanisms, when identified, as well as current recommendations, when available, for monitoring protocols. RECENT FINDINGS Pathogenic mechanisms and cellular target of retinotoxic drugs are often not well characterized but a better knowledge of the course of visual defect has recently helped in defining more relevant monitoring protocols especially for antimalarials and vigabatrin. Mechanisms of ototoxicity have recently been better defined, from inner ear entry with the use of fluorescent tracers to evidence for the role of oxidative stress and program cell death pathways. SUMMARY Experimental and clinical studies have elucidated some of the pathogenic mechanisms, courses and risk factors of retinal toxicity and ototoxicity, which have led to establishment of relevant monitoring protocols. Further studies are, however, warranted to better understand cellular pathways leading to degeneration. These would help to build more efficient preventive intervention and may also contribute to understanding of other degenerative processes such as genetic disorders.
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Abstract
Vigabatrin is an irreversible inhibitor of γ-aminobutyric acid (GABA) transaminase. It is effective as adjunctive therapy for adult patients with refractory complex partial seizures (rCPS) who have inadequately responded to several alternative treatments and as monotherapy for children aged 1 month to 2 years with infantile spasms. The well-documented safety profile of vigabatrin includes risk of retinopathy characterized by irreversible, bilateral, concentric peripheral visual field constriction. Thus, monitoring of visual function to understand the occurrence and manage the potential consequences of peripheral visual field defects (pVFDs) is now required for all patients who receive vigabatrin. However, screening for pVFDs for patients with epilepsy was conducted only after the association between vigabatrin and pVFDs was established. We examined the potential association between pVFDs and epilepsy in vigabatrin-naïve patients and attempted to identify confounding factors (e.g., concomitant medications, method of vision assessment) to more accurately delineate the prevalence of pVFDs directly associated with vigabatrin. Results of a prospective cohort study as well as several case series and case reports suggest that bilateral visual field constriction is not restricted to patients exposed to vigabatrin but has also been detected, although much less frequently, in vigabatrin-naïve patients with epilepsy, including those who received treatment with other GABAergic antiepileptic therapy. We also reviewed published data suggesting an association between vigabatrin-associated retinal toxicity and taurine deficiency, as well as the potential role of taurine in the prevention of this retinopathy.
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Affiliation(s)
- G T Plant
- Department of Neuro-Ophthalmology, National Hospital for Neurology and Neurosurgery, London, UK.
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Kjellström U, Andréasson S, Ponjavic V. Electrophysiological evaluation of retinal function in children receiving vigabatrin medication. J Pediatr Ophthalmol Strabismus 2011; 48:357-65. [PMID: 21261244 DOI: 10.3928/01913913-20110118-01] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 12/01/2010] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate retinal function in children taking vigabatrin and to explore the influence of age and dose parameters on the results of full-field electroretinography (ff-ERG). METHODS The ff-ERGs from 14 children receiving vigabatrin were compared with ff-ERGs from healthy controls. Treated children were further grouped according to age (pre-school = 12-71 months; older = 72-228 months). Parameters of drug dosage were compared. RESULTS Treated children showed rod and cone dysfunction reflected by reduced b-wave amplitudes for the isolated rod response, the combined rod-cone response, and the 30-Hz flicker response. The a-wave amplitude and implicit time for the combined rod-cone response, reflecting photoreceptor function, were also altered. Further evaluation of age groups revealed similar findings in the pre-school group but not in the older group. Alterations in ff-ERG were seen in 57% of the treated children. Pre-school children had received significantly higher daily drug doses with start of medication at younger age. No differences were found concerning cumulative doses or duration of medication. CONCLUSION Alterations in ff-ERG are as frequent in children as in adults and the results indicate that exposure to high daily doses of vigabatrin may be associated with increased risk of retinal dysfunction, including photoreceptor damage, not previously shown in children. Thus, recommendations of careful follow-up for children receiving vigabatrin are supported.
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Moseng L, Sæter M, Mørch-Johnsen GH, Hoff JM, Gajda A, Brodtkorb E, Midelfart A. Retinal nerve fibre layer attenuation: clinical indicator for vigabatrin toxicity. Acta Ophthalmol 2011; 89:452-8. [PMID: 21251242 DOI: 10.1111/j.1755-3768.2010.02077.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate whether persistent visual field defects among patients exposed once to the antiepileptic drug vigabatrin (VGB) were associated with peripapillary retinal nerve fibre layer thickness (RNFLT) attenuation. METHODS Nine individuals with partial epilepsy and VGB-attributed visual field loss (group 1; 18 eyes) and seven age- and gender-matched individuals with epilepsy and no previous VGB exposure (group 2; 14 eyes) were included in the study. Full-field 120 point screening perimetry out to 60 degrees from central fixation using the Humphrey Field Analyzer was performed. RNFLT was quantified by optical coherence tomography (OCT) using Fast RNFLT protocol, Stratus OCT (3.0) after pupillary dilation. The results from the right eye are presented in this article. RESULTS Among the patients with VGB-attributed visual field loss, five patients had only peripheral field defect (group 1a) and the remaining four had advanced field defects both in the periphery and within 30° from central fixation (group 1b). None of the patients in the control group had manifest visual field loss. The mean RNFLT among the patients with VGB-attributed visual field loss was significantly attenuated compared to the controls [mean total RNFLT: group 1: 75.6 ± 12.7 μm, group 2: 103.5 ± 9.7 μm, mean difference 27.9 μm, (CI 15.9-39.9; p < 0.001)]. RNFLT values classified as borderline according to normative database (Stratus OCT) occurred more frequently among individuals with VGB-attributed visual field loss than in controls (frequency in group 1: 6/9; group 2: 0/7, p = 0.011). The nasal, superior and inferior quadrants of RNFLT in individuals with VGB-attributed visual field loss were significantly attenuated, while no difference was detected in temporal quadrants compared to controls. Both individuals with peripheral and those with advanced visual field losses in the VGB group had attenuated mean total RNFLT compared to controls (p = 0.006, p = 0.002, respectively). Occurrence of borderline classification of total RNFLT ≤5th percentile was more frequent among individuals with advanced visual field loss than among controls (p = 0.048). CONCLUSION Persistent visual field loss attributed to VGB is associated with reduced peripapillary RNFLT and was detected both among patients with advanced and among patients with only peripheral visual field defects. Measurements of RNFLT with OCT might be considered as a diagnostic supplement in the follow-up of patients exposed to vigabatrin.
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Affiliation(s)
- Linda Moseng
- Institute of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
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McCoy B, Wright T, Weiss S, Go C, Westall CA. Electroretinogram changes in a pediatric population with epilepsy: is vigabatrin acting alone? J Child Neurol 2011; 26:729-33. [PMID: 21343605 PMCID: PMC3880362 DOI: 10.1177/0883073810390213] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vigabatrin, a structural analogue of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), is widely used as initial monotherapy in infantile spasms and add on therapy in partial onset seizures. Vigabatrin is associated with retinal toxicity causing constriction of the visual field. Our aim was to assess what effect add-on antiepileptic drug therapy has on the incidence of retinal toxicity in patients being treated with vigabatrin. Medication dosages, duration of treatment, and electroretinogram results were examined in a single center retrospective study. Retinal toxicity was detected in 18 of 160 patients (11.25%) over a 10-year period. A total of 14 (77%) were in the group treated with additional antiepileptic drugs, the other 4 received vigabatrin as monotherapy. We detected a significantly higher percentage of toxicity in the group of patients treated with vigabatrin and additional antiepileptic drugs. Our numbers were not sufficient to detect which drug or combination of drugs might be associated with higher risk.
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Affiliation(s)
- Bláthnaid McCoy
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Thomas Wright
- Division of Ophthalmology, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shelly Weiss
- Division of Neurology, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cristina Go
- Division of Neurology, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carol A. Westall
- Division of Ophthalmology, the Hospital for Sick Children, Toronto, Ontario, Canada
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Besch D, Schiefer U, Eter N, Burth R, Elger CE, Spitznas M, Dietz K. Modelling the topography of absolute defects in patients exposed to the anti-epileptic drug vigabatrin and in normal subjects using automated static suprathreshold perimetry of the entire 80° visual field. Graefes Arch Clin Exp Ophthalmol 2011; 249:1333-43. [PMID: 21380539 DOI: 10.1007/s00417-011-1625-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 12/03/2010] [Accepted: 01/12/2011] [Indexed: 11/25/2022] Open
Abstract
AIM (i) To map the spatial distribution of absolute visual field loss (AL) in patients exposed to vigabatrin and to compare the findings with AL in normal individuals, and (ii) to describe the relationship between the major risk factors for absolute loss (gender, age, cumulative dose), and the severity of field loss, expressed as the number of locations with AL per eye. METHODS Visual field plots were retrospectively reviewed from 428 individuals. Perimetry was done with the Tübingen Automated Perimeter (using a threshold-oriented, marginally supraliminal strategy, 80° eccentricity, 99 test locations). Three hundred and sixty-one individuals were ophthalmologically normal, and 67 were patients exposed to vigabatrin who had performed reliably during perimetry prior to neurosurgery for epilepsy. Two hundred and sixty-six of the 361 normals were included on the empirical basis that they manifested AL at no more than 19 stimulus locations per eye (the 74th percentile). The frequency per eye of AL at each of 99 stimulus locations was determined for the normals and patients. The effects of age, gender and cumulative dose of vigabatrin on the number of ALs per individual was assessed by an analysis of covariance. A stochastic model was developed to determine the 50% probability of AL at each location. RESULTS Thirty-nine of the 67 vigabatrin patients exhibited at least 20 locations with AL. The number of ALs was independent of age (p = 0.7603). The frequency of AL was 14.8% in the peripheral field and 1.0% in the central field (odds ratio 16.7; 95% CI 15.0-18.6%; p < 0.0001). Those exposed to vigabatrin exhibited a frequency of 17.1% ALs, compared to 5.2% for the normal individuals (odds ratio 3.77, 95% CI 3.6-4.0%; p < 0.0001). According to the modelled data, males exhibited 20.9% (95% CI 1.3-44%; p = 0.0360) more absolute losses than did females. The number of absolute losses per person doubled with an increase in cumulative dose of vigabatrin of 936 g (95% CI 775-1181 g). CONCLUSIONS According to this retrospective study, the spatial configuration of absolute defects attributable to vigabatrin indicates sparing of the temporal field up to approximately 60° eccentricity. Such a finding is likely to explain, at least in part, the initially asymptomatic nature of the defect. This study reconfirms a (cumulative) dose effect of vigabatrin on the extent of absolute field loss, with a greater risk for male gender.
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Affiliation(s)
- Dorothea Besch
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
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Krueger DA, Franz DN. Targeting mTOR complex 1 to treat neurological and psychiatric manifestations of tuberous sclerosis complex. FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.10.82] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While tuberous sclerosis complex is a genetic disorder with multiorgan involvement, it is the cerebral lesions and abnormal brain function that are responsible for the highest morbidity in affected individuals and for negatively impacting overall quality of life. Identification and effective treatment of the resultant neurological and psychiatric symptoms can be challenging, and evidence-based management techniques are often lacking to help the clinician provide optimal care for these patients. This article identifies the most significant neurological and psychiatric disorders associated with tuberous sclerosis complex and their current management, as well as exploring recent advances in the use of mTOR complex 1 inhibitors, such as sirolimus or everolimus, to treat these disorders.
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Affiliation(s)
- Darcy A Krueger
- Division of Child Neurology, ML 2015, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - David Neal Franz
- Division of Neurology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
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Aurich-Barrera B, Wilton L, Brown D, Shakir S. Paediatric post-marketing pharmacovigilance: comparison of the adverse event profile of vigabatrin prescribed to children and adults. Pharmacoepidemiol Drug Saf 2011; 20:608-18. [PMID: 21351182 DOI: 10.1002/pds.2105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 12/12/2010] [Accepted: 12/13/2010] [Indexed: 11/08/2022]
Abstract
PURPOSE Post-marketing pharmacovigilance is a cornerstone of monitoring and evaluating the safety of medicines in children and adults. However the methods may require modification to detect paediatric signals. The aim of this study was to compare the adverse event (AE) profile of children and adults taking vigabatrin, using modified signal detection methods (SDMs). METHODS Data from the vigabatrin prescription-event monitoring study an observational cohort study (cohort 10,177 patients), stratified into one paediatric (0-17 years) and one adult (≥ 18 years) age group were examined using summary statistics for adverse drug reactions (ADRs), reasons for stopping and deaths. Incidence densities of AEs in children and adults in the first month of treatment were compared to months two to six to examine whether the AE rate was different in these two periods. AE rates in children were compared to those in adults (proportional reporting rates; PRRs and incidence rate ratios), to compare the AE profile between these age groups. RESULTS Abnormal behaviour (PRR 5.3) and hyperactivity (PRR 4.5) were more frequently reported in children; confusion (PRR 25.0) and psychosis (PRR 12.5) more frequently in adults. In children 11.8% of ADRs were reported to the regulatory authority compared to 27.3% in adults. A higher proportion of children stopped treatment due to lack of effectiveness (57.7% vs. 47.5%). No deaths were attributed to vigabatrin. CONCLUSION This study demonstrated that modified SDMs can be used to detect differences in the AE profiles between children and adults taking a medicinal product, and also to identify drug safety signals.
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Affiliation(s)
- Beate Aurich-Barrera
- Drug Safety Reseach Unit, Department of Drug Safety, Bursledon Hall, Blundell Lane, Southampton, UK
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Sergott RC, Bittman RM, Christen EM, Sagar SM. Vigabatrin-induced peripheral visual field defects in patients with refractory partial epilepsy. Epilepsy Res 2010; 92:170-6. [DOI: 10.1016/j.eplepsyres.2010.09.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/27/2010] [Accepted: 09/13/2010] [Indexed: 11/25/2022]
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Abstract
PURPOSE OF REVIEW Although vigabatrin has been used for many years in Europe, this antiepileptic medication was approved for use in the USA only 1 year ago because of concerns for irreversible peripheral visual field loss that can result in functional visual disability. RECENT FINDINGS Visual function testing involves both subjective and objective techniques, some of which can be standardized across multiple centers. With these subjective and objectives issues as a reference, the current literature about the pathogenesis of vigabatrin visual toxicity is reviewed in order to develop a practical and reliable testing program for detecting peripheral visual field changes early in their course; thereby, hopefully limiting disabling visual field loss. SUMMARY Based upon the existing literature as well as the currently available data about the evaluation of visual function, an algorithm has been developed to serve as a starting point for clinicians to evaluate patients treated with vigabatrin for refractory epilepsy.
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Maguire MJ, Hemming K, Wild JM, Hutton JL, Marson AG. Prevalence of visual field loss following exposure to vigabatrin therapy: A systematic review. Epilepsia 2010; 51:2423-31. [DOI: 10.1111/j.1528-1167.2010.02772.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Tuberous sclerosis complex (TSC) is an important cause of epilepsy and autism, as well as renal and pulmonary disease in adults and children. Affected individuals are subject to hamartomas in various organ systems which result from constitutive activation of the protein kinase mTOR (mammalian target of rapamycin). The clinical course, prognosis and appropriate therapy for TSC patients are often different from that for individuals with epilepsy, renal tumors, or interstitial lung disease, from other causes. Additionally, TSC serves as a model for other conditions in which the mTOR pathways are also up-regulated. This article reviews the molecular pathophysiology and management of neurological, renal and pulmonary manifestations of the disorder. The use of mTOR inhibitors such as rapamycin and everolimus is discussed and recent clinical trials of these drugs in TSC are reviewed.
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Affiliation(s)
- D N Franz
- Department of Pediatrics, University of Cincinnati College of Medicine, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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Sergott RC, Wheless JW, Smith MC, Westall CA, Kardon RH, Arnold A, Foroozan R, Sagar SM. Evidence-based Review of Recommendations for Visual Function Testing in Patients Treated with Vigabatrin. Neuroophthalmology 2010. [DOI: 10.3109/01658100903582498] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Di Rosa G, Malaspina P, Blasi P, Dionisi-Vici C, Rizzo C, Tortorella G, Crutchfield SR, Gibson KM. Visual evoked potentials in succinate semialdehyde dehydrogenase (SSADH) deficiency. J Inherit Metab Dis 2009; 32 Suppl 1:S201-5. [PMID: 19484191 PMCID: PMC2888988 DOI: 10.1007/s10545-009-1154-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/17/2009] [Accepted: 04/23/2009] [Indexed: 10/20/2022]
Abstract
In mammals, increased GABA in the central nervous system has been associated with abnormalities of visual evoked potentials (VEPs), predominantly manifested as increased latency of the major positive component P100. Accordingly, we hypothesized that patients with a defect in GABA metabolism, succinate semialdehyde dehydrogenase (SSADH) deficiency (in whom supraphysiological levels of GABA accumulate), would manifest VEP anomalies. We evaluated VEPs on two patients with confirmed SSADH deficiency. Whereas the P100 latencies and amplitudes for binocular VEP analyses were within normal ranges for both patients, the P100 latencies were markedly delayed for left eye (OS) (and right eye (OD), patient 1) and monocular OS (patient 2): 134-147 ms; normal <118 ms. We hypothesize that elevated GABA in ocular tissue of SSADH patients leads to a use-dependent downregulation of the major GABAergic receptor in eye, GABA(C), and that the VEP recordings' abnormalities, as evidenced by P100 latency and/or amplitude measurements, may be reflective of abnormalities within visual systems. This is a preliminary finding that may suggest the utility of performing VEP analysis in a larger sample of SSADH-deficient patients, and encourage a neurophysiological assessment of GABA(C) receptor function in Aldh5a1(-/-) mice to reveal new pathophysiological mechanisms of this rare disorder of GABA degradation.
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Affiliation(s)
- G Di Rosa
- Department of Medical and Surgical Pediatrics, Unit of Infantile Neuropsychiatry, University Hospital of Messina, via Consolare Valeria, Messina, 98125, Italy.
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Naili F, Boucart M, Derambure P, Arndt C. Visual impairment at large eccentricity in participants treated by vigabatrin: visual, attentional or recognition deficit? Epilepsy Res 2009; 87:213-22. [PMID: 19800764 DOI: 10.1016/j.eplepsyres.2009.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 08/09/2009] [Accepted: 09/04/2009] [Indexed: 12/01/2022]
Abstract
A relationship between peripheral visual field loss and vigabatrin (VGB) has been reported in several studies but with inconsistent results. We investigated the level of visual processing at which the impairment occurs: attentional or cognitive (recognition) deficit. A simple reaction time task was used as a baseline condition. A spatial attention task measured the benefit and cost for the detection of a target appearing at a cued or at an uncued location. A rapid categorization task assessed object recognition. Performance was tested at eccentricities varying from 30 degrees to 60 degrees on a panoramic screen covering 180 degrees. Participants were patients with epilepsy treated with VGB, patients treated with other drugs and healthy controls. In the VGB group 9 patients exhibited a mild visual field constriction. We observed a general slowing down of response times in participants treated by VGB, especially at 60 degrees eccentricity but their performance remained above chance at large eccentricity in the most complex categorization task. The slowing down of visual processing at large eccentricity for flashed stimuli suggests that VGB treated patients might be impaired at detecting moving objects in the periphery and this may have consequences in behavioural tasks like driving.
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Affiliation(s)
- Fatima Naili
- Laboratory of Neurosciences Fonctionnelles & Pathologies, Université Lille Nord de France, CNRS, France
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Dose-related changes in retinal function and PKC-alpha expression in rabbits on vigabatrin medication. Graefes Arch Clin Exp Ophthalmol 2009; 247:1057-67. [DOI: 10.1007/s00417-009-1093-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 04/13/2009] [Indexed: 10/20/2022] Open
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Jaseja H. Justification of vigabatrin administration in West syndrome patients? Warranting a re-consideration for improvement in their quality of life. Clin Neurol Neurosurg 2009; 111:111-4. [PMID: 18845383 DOI: 10.1016/j.clineuro.2008.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 07/02/2008] [Accepted: 08/02/2008] [Indexed: 02/05/2023]
Abstract
West syndrome (WS) or infantile spasms (IS) is a severe epileptic syndrome associated with poor prognosis and increased morbidity. The exact etio-pathogenesis of the disorder still remains elusive ant therefore the management continues to pose a challenge to the clinicians. Currently, adreno-corticotrophic hormone (ACTH), steroids and vigabatrin (VGB) form the mainstay of its treatment. However, the recent detection of an irreversible visual field defect observed in as high as 30-50% of children treated with vigabatrin has raised concern over the drug's usage. This brief paper is intended to highlight the significance of the irreversible visual toxicity in an already existent mentally challenged state in WS patients, which can lead to a worsening in the disability status of such patients. Therefore, based on the enhancement of handicap by VGB administration it is recommended that a comprehensive review be performed on its continuation in WS patients in order to prevent further deterioration of their quality of life (QOL).
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Affiliation(s)
- Harinder Jaseja
- Physiology Department, G.R. Medical College, Gwalior 474001, M.P., India.
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Lawthom C, Smith PEM, Wild JM. Nasal retinal nerve fiber layer attenuation: a biomarker for vigabatrin toxicity. Ophthalmology 2009; 116:565-71. [PMID: 19168223 DOI: 10.1016/j.ophtha.2008.09.047] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 09/18/2008] [Accepted: 09/25/2008] [Indexed: 10/21/2022] Open
Abstract
PURPOSE To investigate whether nasal peripapillary retinal nerve fiber layer (RNFL) attenuation is associated with visual field loss attributed to the anti-epileptic drug vigabatrin. DESIGN Prospective cross-sectional observational study. PARTICIPANTS Twenty-seven individuals with focal-onset epilepsy exposed to vigabatrin and 13 individuals with focal-onset epilepsy exposed to non-GABAergic anti-epileptic drug monotherapy. METHODS At one visit, suprathreshold perimetry of the central and peripheral field (3-zone, age-corrected Full Field 135 Screening Test) and threshold perimetry of the central field (Program 30-2 and the FASTPAC strategy) were undertaken using the Humphrey Field Analyzer (Carl Zeiss Meditech, Dublin, CA). At a second visit, ocular coherence tomography was undertaken for the right eye using the 3.4 RNFL thickness protocol of the StratusOCT (Carl Zeiss Meditech). MAIN OUTCOME MEASURES The magnitude, for each individual, of the RNFL thickness, averaged across the 4 oblique quadrants, and for each separate quadrant. RESULTS Of the 27 individuals exposed to vigabatrin, 11 (group I) exhibited vigabatrin-attributed visual field loss, 15 exhibited a normal field, and 1 exhibited a homonymous quadrantanopia (group II). All 13 individuals exposed to non-GABAergic therapy had normal fields (group III). All individuals in group I exhibited abnormal average and nasal quadrant RNFL thicknesses in the presence of a normal temporal quadrant thickness. Most also exhibited additional RNFL attenuation in either the superior or inferior quadrant, or both. Four individuals in group II exhibited an identical pattern of RNFL attenuation suggesting that nasal RNFL thinning is a more sensitive marker for vigabatrin toxicity than visual field loss. None of the 13 individuals in group III exhibited nasal quadrant RNFL attenuation. CONCLUSIONS Vigabatrin-attributed visual field loss is associated with a characteristic pattern of RNFL attenuation: nasal quadrant thinning and normal temporal quadrant thickness with, or without, superior or inferior quadrant involvement. Nasal attenuation may precede visual field loss. Ocular coherence tomography of the peripapillary RNFL should be considered in patients previously exposed to vigabatrin. It should also be considered at baseline and follow-up in those commencing vigabatrin for treatment of epilepsy or in trials for anti-addiction therapy. The pattern of RNFL thinning seems to be a useful biomarker to identify vigabatrin toxicity.
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Affiliation(s)
- Charlotte Lawthom
- Welsh Epilepsy Unit, University Hospital of Wales, Cardiff, Wales, United Kingdom
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Waterhouse EJ, Mims KN, Gowda SN. Treatment of refractory complex partial seizures: role of vigabatrin. Neuropsychiatr Dis Treat 2009; 5:505-15. [PMID: 19851518 PMCID: PMC2762367 DOI: 10.2147/ndt.s5236] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Vigabatrin (VGB) is an antiepileptic drug that was designed to inhibit GABA-transaminase, and increase levels of gamma-amino-butyric acid (GABA), a major inhibitory neurotransmitter in the brain. VGB has demonstrated efficacy as an adjunctive antiepileptic drug for refractory complex partial seizures (CPS) and for infantile spasms (IS). This review focuses on its use for complex partial seizures. Although VGB is well tolerated, there have been significant safety concerns about intramyelinic edema and visual field defects. VGB is associated with a risk of developing bilateral concentric visual field defects. Therefore, the use of VGB for complex partial seizures should be limited to those patients with seizures refractory to other treatments. Patients must have baseline and follow-up monitoring of visual fields, early assessment of its efficacy, and ongoing evaluation of the benefits and risks of VGB therapy.
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Affiliation(s)
- Elizabeth J Waterhouse
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
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Abstract
Tuberous sclerosis complex (TSC) is an important cause of epilepsy, autism, and renal and pulmonary disease in children and adults. The clinical course of TSC and the prognosis and appropriate therapy for TSC patients are often different than that for individuals with epilepsy, renal tumors, or interstitial lung disease from other causes. This article reviews the current therapeutic recommendations for medical and surgical management of neurologic, renal, and pulmonary manifestations of TSC. In addition, recent clinical trials using inhibitors of the mammalian target of rapamycin (mTOR) have demonstrated regression of astrocytomas, angiofibromas, and angiomyoliomas, as well as improved pulmonary function in persons with TSC.
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Affiliation(s)
- Darcy A Krueger
- Tuberous Sclerosis Clinic, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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Wang QP, Jammoul F, Duboc A, Gong J, Simonutti M, Dubus E, Craft CM, Ye W, Sahel JA, Picaud S. Treatment of epilepsy: the GABA-transaminase inhibitor, vigabatrin, induces neuronal plasticity in the mouse retina. Eur J Neurosci 2008; 27:2177-87. [PMID: 18412635 DOI: 10.1111/j.1460-9568.2008.06175.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vigabatrin was a major drug in the treatment of epilepsy until the discovery that it was associated with an irreversible constriction of the visual field. Nevertheless, the drug is still prescribed for infantile spasms and refractory epilepsy. Disorganization of the photoreceptor nuclear layer and cone photoreceptor damage have been described in albino rats. To investigate the vigabatrin-elicited retinal toxicity further, we examined the retinal tissue of albino mice treated with two vigabatrin doses. The higher dose did not always cause the photoreceptor layer disorganization after 1 month of treatment. However, it triggered a massive synaptic plasticity in retinal areas showing a normal layering of the retina. This plasticity was shown by the withdrawal of rod but not cone photoreceptor terminals from the outer plexiform layers towards their cell bodies. Furthermore, both rod bipolar cells and horizontal cells exhibited dendritic sprouting into the photoreceptor nuclear layer. Withdrawing rod photoreceptors appeared to form ectopic contacts with growing postsynaptic dendrites. Indeed, contacts between rods and bipolar cells, and between bipolar cells and horizontal cells were observed deep inside the outer nuclear layer. This neuronal plasticity is highly suggestive of an impaired glutamate release by photoreceptors because similar observations have been reported in different genetically modified mice with deficient synaptic transmission. Such a synaptic deficit is consistent with the decrease in glutamate concentration induced by vigabatrin. This description of the neuronal plasticity associated with vigabatrin provides new insights into its retinal toxicity in epileptic patients.
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Affiliation(s)
- Qing-Ping Wang
- INSERM UMRS-592, Laboratoire de Physiopathologie Cellulaire et Moléculaire de la Rétine, Paris, France
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The ocular side effects of vigabatrin (Sabril): information and guidance for screening. Eye (Lond) 2008; 22:1097-8. [PMID: 18497834 DOI: 10.1038/eye.2008.139] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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