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Jonsson H, Lehto M, Vanhatalo S, Gaily E, Linnankivi T. Visual field defects after vigabatrin treatment during infancy: retrospective population-based study. Dev Med Child Neurol 2022; 64:641-648. [PMID: 34716587 DOI: 10.1111/dmcn.15099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 02/02/2023]
Abstract
AIM To investigate the prevalence of vigabatrin-attributed visual field defect (VAVFD) in infantile spasms and the utility of optical coherence tomography (OCT) in detecting vigabatrin-related damage. METHOD We examined visual fields by Goldmann or Octopus perimetry and the thickness of peripapillary retinal nerve fiber layer (RNFL) with spectral-domain OCT at school age or adolescence. RESULTS Out of 88 patients (38 females, mean age at study 15y, SD 4y 3mo, range 6y 4mo-23y 3mo [n=65] or deceased [n=21] or moved abroad [n=2]) exposed to vigabatrin in infancy, 28 were able to perform formal visual field testing. Two had visual field defect from structural causes. We found mild VAVFD in four patients and severe VAVFD in one patient. Median vigabatrin treatment duration for those with normal visual field was 11 months compared to 19 months for those with VAVFD (p=0.04). OCT showed concomitant attenuated RNFL in three children with VAVFD, and was normal in one. The temporal half of the peripapillary RNFL was significantly thinner in the VAVFD group compared to the normal visual field group. INTERPRETATION The overall prevalence of VAVFD is lower after exposure in infancy compared to 52% which has been reported after exposure in adulthood. The risk increases with longer treatment duration. Further studies should identify infants particularly susceptible to VAVFD and clarify the role of OCT.
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Affiliation(s)
- Henna Jonsson
- Department of Pediatric Neurology, New Children's Hospital and Pediatric Research Center, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Mikko Lehto
- Department of Ophthalmology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sampsa Vanhatalo
- Department of Children's Clinical Neurophysiology, BABA Center, Department of Clinical Neurophysiology, Children's Hospital, Helsinki University Hospital, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eija Gaily
- Department of Pediatric Neurology, New Children's Hospital and Pediatric Research Center, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Tarja Linnankivi
- Department of Pediatric Neurology, New Children's Hospital and Pediatric Research Center, Epilepsia Helsinki, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Chan K, Hoon M, Pattnaik BR, Ver Hoeve JN, Wahlgren B, Gloe S, Williams J, Wetherbee B, Kiland JA, Vogel KR, Jansen E, Salomons G, Walters D, Roullet JB, Gibson K M, McLellan GJ. Vigabatrin-Induced Retinal Functional Alterations and Second-Order Neuron Plasticity in C57BL/6J Mice. Invest Ophthalmol Vis Sci 2020; 61:17. [PMID: 32053727 PMCID: PMC7326505 DOI: 10.1167/iovs.61.2.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/07/2019] [Indexed: 12/13/2022] Open
Abstract
Purpose Vigabatrin (VGB) is an effective antiepileptic that increases concentrations of inhibitory γ-aminobutyric acid (GABA) by inhibiting GABA transaminase. Reports of VGB-associated visual field loss limit its clinical usefulness, and retinal toxicity studies in laboratory animals have yielded conflicting results. Methods We examined the functional and morphologic effects of VGB in C57BL/6J mice that received either VGB or saline IP from 10 to 18 weeks of age. Retinal structure and function were assessed in vivo by optical coherence tomography (OCT), ERG, and optomotor response. After euthanasia, retinas were processed for immunohistochemistry, and retinal GABA, and VGB quantified by mass spectrometry. Results No significant differences in visual acuity or total retinal thickness were identified between groups by optomotor response or optical coherence tomography, respectively. After 4 weeks of VGB treatment, ERG b-wave amplitude was enhanced, and amplitudes of oscillatory potentials were reduced. Dramatic rod and cone bipolar and horizontal cell remodeling, with extension of dendrites into the outer nuclear layer, was observed in retinas of VGB-treated mice. VGB treatment resulted in a mean 3.3-fold increase in retinal GABA concentration relative to controls and retinal VGB concentrations that were 20-fold greater than brain. Conclusions No evidence of significant retinal thinning or ERG a- or b-wave deficits were apparent, although we describe significant alterations in ERG b-wave and oscillatory potentials and in retinal cell morphology in VGB-treated C57BL/6J mice. The dramatic concentration of VGB in retina relative to the target tissue (brain), with a corresponding increase in retinal GABA, offers insight into the pathophysiology of VGB-associated visual field loss.
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Affiliation(s)
- Kore Chan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Mrinalini Hoon
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Bikash R. Pattnaik
- McPherson Eye Research Institute, Madison, Wisconsin, United States
- Pediatrics Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - James N. Ver Hoeve
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Brad Wahlgren
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Shawna Gloe
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Jeremy Williams
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Brenna Wetherbee
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Julie A. Kiland
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Kara R. Vogel
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Erwin Jansen
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Gajja Salomons
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Dana Walters
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Jean-Baptiste Roullet
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - K Michael Gibson
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Gillian J. McLellan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
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McFarlane MT, Wright T, McCoy B, Snead OC, Westall CA. Retinal defect in children with infantile spasms of varying etiologies: An observational study. Neurology 2019; 94:e575-e582. [PMID: 31792095 DOI: 10.1212/wnl.0000000000008686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 08/11/2019] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the prevalence of retinal defect in children with infantile spasms (IS) unrelated to treatment with vigabatrin and clarify if specific primary etiologies for IS are associated with retinal defect more than others. METHODS This was an observational cohort study including 312 patients (176 male, 136 female) with IS who were vigabatrin-naive. Participants ranged from 1.7 to 34.7 months of age (mean 8.8 months). Electroretinograms (ERGs) were performed according to the International Society for Clinical Electrophysiology of Vision. Retinal defect was identified as abnormal if the 30-Hz flicker ERG amplitude was lower than the age-corrected normal 95% prediction interval. The primary etiology for IS, as determined by the treating pediatric neurologist(s), was obtained from patient health records and classified into 1 of 9 etiologic subgroups: (1) genetic disorders alone, (2) genetic-structural disorders, (3) structural-congenital, (4) structural-acquired (perinatal), (5) structural-acquired (postnatal), (6) metabolic disorders, (7) immunologic disorders, (8) infectious, and (9) unknown causes. RESULTS Fifty-nine of the 312 vigabatrin-naive children (18.9%) showed retinal defect and the prevalence of retinal defect was highest (24.4%) in the structural-acquired (perinatal) subgroup, which included hypoxic-ischemic defect. Retinal function compared across subgroups showed no significant difference. CONCLUSIONS Care is required in diagnosing retinal toxicity, which would be enhanced by baseline flicker ERG in children with IS prior to starting vigabatrin.
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Affiliation(s)
- Michelle T McFarlane
- From the Departments of Ophthalmology and Vision Sciences (M.T.M., C.A.W.) and Neurology (B.M., O.C.S.), The Hospital for Sick Children; Kensington Eye Institute (T.W.), Toronto; and Institute of Medical Science (O.C.S., C.A.W.) and Ophthalmology and Vision Sciences (C.A.W.), University of Toronto, Canada
| | - Tom Wright
- From the Departments of Ophthalmology and Vision Sciences (M.T.M., C.A.W.) and Neurology (B.M., O.C.S.), The Hospital for Sick Children; Kensington Eye Institute (T.W.), Toronto; and Institute of Medical Science (O.C.S., C.A.W.) and Ophthalmology and Vision Sciences (C.A.W.), University of Toronto, Canada
| | - Blathnaid McCoy
- From the Departments of Ophthalmology and Vision Sciences (M.T.M., C.A.W.) and Neurology (B.M., O.C.S.), The Hospital for Sick Children; Kensington Eye Institute (T.W.), Toronto; and Institute of Medical Science (O.C.S., C.A.W.) and Ophthalmology and Vision Sciences (C.A.W.), University of Toronto, Canada
| | - O Carter Snead
- From the Departments of Ophthalmology and Vision Sciences (M.T.M., C.A.W.) and Neurology (B.M., O.C.S.), The Hospital for Sick Children; Kensington Eye Institute (T.W.), Toronto; and Institute of Medical Science (O.C.S., C.A.W.) and Ophthalmology and Vision Sciences (C.A.W.), University of Toronto, Canada
| | - Carol A Westall
- From the Departments of Ophthalmology and Vision Sciences (M.T.M., C.A.W.) and Neurology (B.M., O.C.S.), The Hospital for Sick Children; Kensington Eye Institute (T.W.), Toronto; and Institute of Medical Science (O.C.S., C.A.W.) and Ophthalmology and Vision Sciences (C.A.W.), University of Toronto, Canada.
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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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Akula JD, Noonan ER, Di Nardo A, Favazza TL, Zhang N, Sahin M, Hansen RM, Fulton AB. Vigabatrin can enhance electroretinographic responses in pigmented and albino rats. Doc Ophthalmol 2015; 131:1-11. [PMID: 25761928 DOI: 10.1007/s10633-015-9491-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/23/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effects of the antiepileptic medication vigabatrin (VGB) on the retina of pigmented rats. METHODS Scotopic and photopic electroretinograms were recorded from dark- and light-adapted Long-Evans (pigmented) and Sprague Dawley (albino) rats administered, daily, 52-55 injections of 250 mg·kg(-1)·day(-1) VGB or 25-26 injections of 500 mg·kg(-1)·day(-1) VGB, or a corresponding number of sham injections. Sensitivity and saturated amplitude of the rod photoresponse (S, Rm(P3)) and postreceptor response (1/σ, Vm) were derived, as were sensitivity and amplitude of the cone-mediated postreceptor response (1/σ(cone), Vm(cone)). The oscillatory potentials and responses to a series of flickering lights (6.25, 12.5, 25 and 50 Hz) were studied in the time and frequency domains. A subset of rats' eyes was harvested for Western blotting or histology. RESULTS Of the parameters derived from dark-adapted ERG responses, in both pigmented and albino rats, VGB repeatedly and reliably enhanced electroretinographic parameters; no significant ERG deficits were noted. No significant alterations were observed in ER/oxidative stress or in the Akt cell death/survival pathway. There were migrations of photoreceptor nuclei toward the RPE and outgrowths of bipolar cell dendrites into the outer nuclear layer in VGB-treated rats; these were never observed in sham-treated animals. CONCLUSIONS Although VGB is associated with retinal dysfunction in patients and VGB toxicity has been demonstrated by other laboratories in the albino rat, in our pigmented and albino rats, VGB did not induce deficits in, but rather enhanced, retinal function. Nonetheless, retinal neuronal dysplasia was observed.
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Riikonen R, Rener-Primec Z, Carmant L, Dorofeeva M, Hollody K, Szabo I, Krajnc BS, Wohlrab G, Sorri I. Does vigabatrin treatment for infantile spasms cause visual field defects? An international multicentre study. Dev Med Child Neurol 2015; 57:60-7. [PMID: 25145415 DOI: 10.1111/dmcn.12573] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/03/2014] [Indexed: 11/30/2022]
Abstract
AIM The aim of this study was to examine whether vigabatrin treatment had caused visual field defects (VFDs) in children of school age who had received the drug in infancy. METHOD In total, 35 children (14 males, 21 females; median age 11y, SD 3.4y, range 8-23y) were examined by static Humphrey perimetry, Goldmann kinetic perimetry, or Octopus perimetry. The aetiologies of infantile spasms identified were tuberous sclerosis (n=10), other symptomatic causes (n=3), or cryptogenic (n=22). RESULTS Typical vigabatrin-attributed VFDs were found in 11 out of 32 (34%) children: in one out of 11 children (9%) who received vigabatrin for <1 year (group 1), in three out of 10 children (30%) who received vigabatrin for 12 to 24 months (group 2), and in seven out of 11 children (63%) who received vigabatrin treatment for longer than 2 years (group 3). VFDs were mild in five and severe in six children. Patients with tuberous sclerosis were at higher risk of VFDs (six out of 10 children). The mean cumulative doses of vigabatrin were 140.5, 758.8, and 2712g in group 1, 2, and 3, respectively. INTERPRETATION VFDs were found in 34% of the cohort of children in this study. The rate of VFD increased from 9% to 63% as duration of treatment increased. The results of this study showed that the risk-benefit ratio should always be considered when using vigabatrin.
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Affiliation(s)
- Raili Riikonen
- Children's Hospital, Kuopio University Hospital, Kuopio, Finland
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Westall CA, Wright T, Cortese F, Kumarappah A, Snead OC, Buncic JR. Vigabatrin retinal toxicity in children with infantile spasms: An observational cohort study. Neurology 2014; 83:2262-8. [PMID: 25381295 PMCID: PMC4277676 DOI: 10.1212/wnl.0000000000001069] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 07/07/2014] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES To determine time to vigabatrin (VGB, Sabril; Lundbeck, Deerfield, IL) induced retinal damage in children with infantile spasms (IS) and to identify risk factors for VGB-induced retinal damage (VGB-RD). METHODS Observational cohort study including 146 participants (68 female, 81 male) with IS, an age-specific epilepsy syndrome of early infancy, treated with VGB. Participants ranged from 3 to 34.9 months of age (median 7.6 months). The median duration of VGB treatment was 16 months (range 4.6-78.5 months). Electroretinograms (ERGs) were performed according to the Standards of the International Society for Clinical Electrophysiology of Vision. Inclusion required baseline (pre-VGB or within 4 weeks of starting VGB treatment) and at least 2 follow-up ERGs. Significant reduction from baseline of the 30-Hz ERG flicker amplitude on 2 consecutive visits identified VGB-RD. Kaplan-Meier survival analyses depicted the effect of duration of VGB on VGB-RD. RESULTS These data represent the largest survival analysis of children treated with VGB who did not succumb to retinal toxicity during the study. Thirty of the 146 participants (21%) showed VGB-RD. The ERG amplitude reduced with duration of VGB treatment (p = 0.0004) with no recovery after VGB cessation. With 6 and 12 months of VGB treatment, 5.3% and 13.3%, respectively, developed VGB-RD. There was neither effect of age of initiation of VGB treatment nor sex of the child on survival statistics and no significant effect of cumulative dosage on the occurrence of VGB-RD. CONCLUSIONS Minimizing VGB treatment to 6 months will reduce the prevalence of VGB-RD in patients with IS.
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Affiliation(s)
- Carol A Westall
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada.
| | - Tom Wright
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada
| | - Filomeno Cortese
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada
| | - Ananthavalli Kumarappah
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada
| | - O Carter Snead
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada
| | - Joseph R Buncic
- From the Department of Ophthalmology and Vision Science (C.A.W., T.W., A.K., J.R.B.), and Faculty of Medicine (O.C.S.), The Hospital for Sick Children, University of Toronto (C.A.W., J.R.B., O.C.S.); and Hotchkiss Brain Institute, University of Calgary (F.C.), Canada
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Changes in the ERG d-wave with vigabatrin treatment in a pediatric cohort. Doc Ophthalmol 2014; 129:97-104. [PMID: 25008578 DOI: 10.1007/s10633-014-9453-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 06/24/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE Vigabatrin (VGB), a treatment for the childhood epilepsy, infantile spasms (IS), is implicated in visual field constriction. Electroretinograms (ERGs) are used as a substitute for visual field testing in infants. We use the VGB-associated ERG reduction (VAER), defined as reduction in age-corrected light adapted 30 Hz flicker amplitude from a pre-treatment measurement in the absence of other retinal defects, as an indicator of retinal toxicity resulting from VGB use. The d-wave ERG response is predominantly the result of OFF-bipolar cell depolarization response to light offset. The purpose of this study is to evaluate the ERG d-wave response as a marker for VAER toxicity in an infant population. METHODS One hundred children with IS treated with VGB (median age at baseline: 7.6 months; range 1.7-38.4) were tested for the cone-OFF response elicited to a 250 cd s m(2) flash with 200 ms duration (long flash ERG). Diagnosis of VAER requires baseline testing of the flicker ERG and at least one follow up ERG; Fifty-one patients fulfilled this criteria. Fifty-eight children received the long flash ERG at baseline. Thirteen retinally normal controls with a median age of 32 months (5.7-65) were also tested. Amplitude and implicit time of the d-wave response were measured manually. RESULTS Longer duration of treatment was associated with reduced d-wave amplitude (ANOVA p < 0.05) in patients taking VGB. Nine patients demonstrated VAER during the course of the study. D-wave amplitude was reduced in the IS group with VAER compared to those without VAER (p < 0.05). CONCLUSIONS Vigabatrin associated retinal defects may be reflected in reduction of the cone d-wave amplitude.
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Sergott RC, Westall CA. Primer on visual field testing, electroretinography, and other visual assessments for patients treated with vigabatrin. Acta Neurol Scand 2012:48-56. [PMID: 22061180 DOI: 10.1111/j.1600-0404.2011.01600.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vigabatrin, an irreversible inhibitor of γ-aminobutyric acid transaminase, is an antiepileptic drug indicated in the United States as adjunctive therapy for adult patients with refractory complex partial seizures who have responded inadequately to several alternative treatments and for monotherapy treatment of infantile spasms in patients 1 month to 2 years of age. Approval of vigabatrin in the United States was contingent on the implementation of a Risk Evaluation and Mitigation Strategy (REMS) to manage the threat of a progressive, permanent bilateral concentric peripheral visual field defects (pVFDs) that may occur in patients treated with vigabatrin. The REMS is designed to promote compliance with evidence-based recommendations for baseline (within 4 weeks of the start of treatment) ophthalmologic evaluations and ongoing vision monitoring in all patients treated with vigabatrin. In view of the challenges associated with visual field testing in patients with epilepsy and in infants, clinicians must understand the qualitative (pattern of damage), quantitative (degree of damage), electrophysiologic, and adjunctive techniques recommended for monitoring vigabatrin-treated patients. The objectives of ongoing research are to characterize the onset, progression, and risk of developing vision loss during the first year of vigabatrin treatment and to evaluate the potential of noninvasive imaging as a method for monitoring retinal changes corresponding to the pVFD. This article provides an overview of visual field testing procedures and electroretinography, summarizes the clinical characteristics of vigabatrin-associated pVFDs, and provides recommendations for visual field and visual electrophysiology testing relevant to both adult and infant patients treated with vigabatrin.
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Affiliation(s)
- R C Sergott
- Wills Eye Institute, Neuro-Ophthalmology Service, Thomas Jefferson University Medical College, Philadelphia, PA 19107, USA.
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Abstract
Vigabatrin is an effective and well-tolerated antiepileptic drug (AED) for the treatment of refractory complex partial seizures (rCPS) and infantile spasms (IS), but its benefits must be evaluated in conjunction with its risk of retinopathy with the development of peripheral visual field defects (pVFDs). Vigabatrin should be considered for rCPS if a patient has failed appropriate trials of other AEDs or is not a suitable candidate for other AEDs, is not an optimal surgical candidate, and continues to experience debilitating effects from seizures. Vigabatrin is indicated as monotherapy for pediatric patients with IS. Its efficacy in achieving improved seizure control should be apparent within 12 weeks in patients with rCPS and within 2-4 weeks after attaining appropriate dosage for patients with IS. Because 12 weeks is well less than the known time of onset of visual defects, the risk of developing pVFDs may be minimized by discontinuing vigabatrin early during the course of therapy for patients with inadequate response. Appropriate vision screening is recommended at baseline, every 3 months during continued vigabatrin treatment, and at 3-6 months after discontinuation (if therapy has spanned more than a few months). If a pVFD is detected at any point and the decision is made to discontinue therapy, the pVFD is not likely to progress after discontinuation of vigabatrin. Although some patients will be at risk of retinopathy, vigabatrin is an appropriate treatment option for patients who achieve substantial clinical benefit, especially given the severe consequences of rCPS and uncontrolled IS. While retinopathy with the development of pVFDs is a serious adverse event, it is not life-threatening and its risk can be effectively managed.
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Affiliation(s)
- J M Pellock
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Moskowitz A, Hansen RM, Eklund SE, Fulton AB. Electroretinographic (ERG) responses in pediatric patients using vigabatrin. Doc Ophthalmol 2012; 124:197-209. [PMID: 22426576 DOI: 10.1007/s10633-012-9320-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/02/2012] [Indexed: 11/30/2022]
Abstract
The antiepileptic drug vigabatrin is known to cause retinal and visual dysfunction, particularly visual field defects, in some patients. Electroretinography (ERG) is used in an attempt to identify adverse effects of vigabatrin (VGB) in patients who are not candidates for conventional perimetry. We report data from 114 pediatric patients taking VGB referred for clinical evaluation; median age at test was 22.9 (2.4 to 266.1) months, and median duration of VGB use was 9.7 (0.3 to 140.7) months. Twenty-seven of them were tested longitudinally (3 to 12 ERG tests). ERG responses to full-field stimuli were recorded in scotopic and photopic conditions, and results were compared to responses from healthy control subjects. We found that abnormalities of photoreceptor and post-receptor ERG responses are frequent in these young patients. The most frequently abnormal scotopic parameter was post-receptor sensitivity, log σ, derived from the b-wave stimulus-response function; the most frequently abnormal photopic parameter was the implicit time of the OFF response (d-wave) to a long (150 ms) flash. Abnormal 30-Hz flicker response amplitude, previously reported to be a predictor of visual field loss, occurred infrequently. For the group as a whole, none of the ERG parameters changed significantly with increasing duration of VGB use. Four of the 27 patients tested longitudinally showed systematic worsening of log σ with duration of VGB use. In a subset of patients who underwent perimetry (N = 39), there was no significant association of any ERG parameter with visual field defects. We cannot determine whether the ERG abnormalities we found were due solely to the effects of VGB. We caution against over-reliance on the ERG to monitor pediatric patients for VGB toxicity and recommend further development of a reliable test of peripheral vision to supplant ERG testing.
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Affiliation(s)
- Anne Moskowitz
- Department of Ophthalmology, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Pan Y, Gerasimov MR, Kvist T, Wellendorph P, Madsen KK, Pera E, Lee H, Schousboe A, Chebib M, Bräuner-Osborne H, Craft CM, Brodie JD, Schiffer WK, Dewey SL, Miller SR, Silverman RB. (1S, 3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid (CPP-115), a potent γ-aminobutyric acid aminotransferase inactivator for the treatment of cocaine addiction. J Med Chem 2012; 55:357-66. [PMID: 22128851 PMCID: PMC3257419 DOI: 10.1021/jm201231w] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vigabatrin, a GABA aminotransferase (GABA-AT) inactivator, is used to treat infantile spasms and refractory complex partial seizures and is in clinical trials to treat addiction. We evaluated a novel GABA-AT inactivator (1S, 3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid (CPP-115, compound 1) and observed that it does not exhibit other GABAergic or off-target activities and is rapidly and completely orally absorbed and eliminated. By use of in vivo microdialysis techniques in freely moving rats and microPET imaging techniques, 1 produced similar inhibition of cocaine-induced increases in extracellular dopamine and in synaptic dopamine in the nucleus accumbens at (1)/(300) to (1)/(600) the dose of vigabatrin. It also blocks expression of cocaine-induced conditioned place preference at a dose (1)/(300) that of vigabatrin. Electroretinographic (ERG) responses in rats treated with 1, at doses 20-40 times higher than those needed to treat addiction in rats, exhibited reductions in ERG responses, which were less than the reductions observed in rats treated with vigabatrin at the same dose needed to treat addiction in rats. In conclusion, 1 can be administered at significantly lower doses than vigabatrin, which suggests a potential new treatment for addiction with a significantly reduced risk of visual field defects.
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Affiliation(s)
- Yue Pan
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113
| | - Madina R. Gerasimov
- Center for Neurosciences, Feinstein Institute for Medical Research, North Shore - LIJ Health System, Manhasset, New York 11030
| | - Trine Kvist
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark
| | - Petrine Wellendorph
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark
| | - Karsten K. Madsen
- Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark
| | - Elena Pera
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia
| | - Hyunbeom Lee
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113
| | - Arne Schousboe
- Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark
| | - Mary Chebib
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia
| | - Hans Bräuner-Osborne
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark
| | - Cheryl M. Craft
- Mary D. Allen Laboratory for Vision Research, Doheny Eye Institute, Department of Ophthalmology and Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Jonathan D. Brodie
- Psychiatry Department, New York University School of Medicine, New York New York 10016
| | - Wynne K. Schiffer
- Center for Neurosciences, Feinstein Institute for Medical Research, North Shore - LIJ Health System, Manhasset, New York 11030
| | - Stephen L. Dewey
- Center for Neurosciences, Feinstein Institute for Medical Research, North Shore - LIJ Health System, Manhasset, New York 11030
| | - Steven R. Miller
- Catalyst Pharmaceutical Partners, Inc., Coral Gables, Florida 33134
| | - Richard B. Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113
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Pellock JM, Faught E, Sergott RC, Shields WD, Burkhart GA, Krauss GL, Foroozan R, Wesche DL, Weinberg MA. Registry initiated to characterize vision loss associated with vigabatrin therapy. Epilepsy Behav 2011; 22:710-7. [PMID: 21978471 DOI: 10.1016/j.yebeh.2011.08.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/25/2011] [Accepted: 08/26/2011] [Indexed: 10/16/2022]
Abstract
The vigabatrin patient registry was implemented in August 2009 in conjunction with Food and Drug Administration approval of vigabatrin. All US vigabatrin-treated patients must enroll in the registry. Data on prescriber specialty/location, patient demographics, and clinical characteristics are collected. Benefit-risk assessments are required early in the course of therapy. Vision assessments are required at baseline (≤4 weeks after therapy initiation), every 3 months during therapy, and 3 to 6 months after discontinuation. As of February 1, 2011, 2473 patients (1500 with infantile spasms, 846 with refractory complex partial seizures, 120 with other diagnoses) had enrolled; 30.4% were previously exposed to vigabatrin. Kaplan-Meier analysis of time in registry indicated that 83 and 97% of all enrolled patients with refractory complex partial seizures and infantile spasms remained beyond 3 and 1 month, respectively. The ongoing registry will provide visual status and other information on vigabatrin-treated patients for both the infantile spasm and refractory complex partial seizure indications.
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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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