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Potschka H, Fischer A, Löscher W, Volk HA. Pathophysiology of drug-resistant canine epilepsy. Vet J 2023; 296-297:105990. [PMID: 37150317 DOI: 10.1016/j.tvjl.2023.105990] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Drug resistance continues to be a major clinical problem in the therapeutic management of canine epilepsies with substantial implications for quality of life and survival times. Experimental and clinical data from human medicine provided evidence for relevant contributions of intrinsic severity of the disease as well as alterations in pharmacokinetics and -dynamics to failure to respond to antiseizure medications. In addition, several modulatory factors have been identified that can be associated with the level of therapeutic responses. Among others, the list of potential modulatory factors comprises genetic and epigenetic factors, inflammatory mediators, and metabolites. Regarding data from dogs, there are obvious gaps in knowledge when it comes to our understanding of the clinical patterns and the mechanisms of drug-resistant canine epilepsy. So far, seizure density and the occurrence of cluster seizures have been linked with a poor response to antiseizure medications. Moreover, evidence exists that the genetic background and alterations in epigenetic mechanisms might influence the efficacy of antiseizure medications in dogs with epilepsy. Further molecular, cellular, and network alterations that may affect intrinsic severity, pharmacokinetics, and -dynamics have been reported. However, the association with drug responsiveness has not yet been studied in detail. In summary, there is an urgent need to strengthen clinical and experimental research efforts exploring the mechanisms of resistance as well as their association with different etiologies, epilepsy types, and clinical courses.
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
| | - Andrea Fischer
- Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Holger A Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany
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2
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Charalambous M, Shivapour SK, Brodbelt DC, Volk HA. Antiepileptic drugs' tolerability and safety--a systematic review and meta-analysis of adverse effects in dogs. BMC Vet Res 2016; 12:79. [PMID: 27206489 PMCID: PMC4875685 DOI: 10.1186/s12917-016-0703-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 05/12/2016] [Indexed: 01/16/2023] Open
Abstract
Background The safety profile of anti-epileptic drugs (AEDs) is an important consideration for the regulatory bodies, owners and prescribing clinicians. Information on their adverse effects still remains limited. A systematic review including a meta-analytic approach was designed to evaluate existing evidence for the safety profile of AEDs in canine patients. Electronic searches of PubMed, CAB Direct and Google scholar were carried out without date or language restrictions. Conference proceedings were also searched. Peer-reviewed full-length studies reporting adverse effects of AEDs in epileptic and healthy non-epileptic dogs were included. Studies were allocated to three groups based on their design. Individual studies were evaluated based on the quality of evidence (study design, study group sizes, subject enrolment quality and overall risk of bias) and the outcome measures reported (proportion of specific adverse effects for each AED, prevalence and 95 % confidence interval of the affected population in each study and comparative odds ratio of adverse effects for AEDs). Results Ninety studies, including six conference proceedings, reporting clinical outcomes of AEDs’ adverse effects were identified. Few studies were designed as blinded randomised controlled clinical trials. Many studies included low canine populations with unclear criteria of subject enrolment and short treatment periods. Direct comparisons suggested that imepitoin and levetiracetam might have a better safety profile than phenobarbital, whilst the latter might have a better safety profile than potassium bromide. However, none of these comparisons showed a statistically significant difference. Comparisons between other AEDs were not possible as a considerable amount of studies lacked power calculations or adequate data to allow further statistical analysis. Individual AED assessments indicated that levetiracetam might be one of the safest AEDs, followed by imepitoin and then phenobarbital and potassium bromide; these findings were all supported by a strong level of evidence. The safety profile in other AEDs was variable, but weak evidence was found to permit firm conclusions or to compare their safety to other AEDs. Conclusions This systematic review provides objective evaluation of the most commonly used AEDs’ adverse effects. Adverse effects usually appeared mild in all AEDs and subsided once doses and/or serum levels were monitored or after the AED was withdrawn. Although phenobarbital might be less safe than imepitoin and levetiracetam, there was insufficient evidence to classify it as an AED with a high risk of major adverse effects. It is important for clinicians to evaluate both AEDs’ effectiveness and safety on an individual basis before the selection of the appropriate monotherapy or adjunctive AED therapy.
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Affiliation(s)
- Marios Charalambous
- Faculty of Brain Sciences, UCL Institute of Neurology, University College London, London, WC1E 6BT, UK.
| | - Sara K Shivapour
- College of Veterinary Medicine, Iowa State University, Ames, Iowa, 50011, USA
| | - David C Brodbelt
- Department of Production and Population Health, Royal Veterinary College, Hawkshead Lane, Hatfield, Herts, AL9 7TA, UK
| | - Holger A Volk
- Department of Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, Hatfield, Herts, AL9 7TA, UK
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Dodi PL. Immune-mediated keratoconjunctivitis sicca in dogs: current perspectives on management. VETERINARY MEDICINE-RESEARCH AND REPORTS 2015; 6:341-347. [PMID: 30101119 PMCID: PMC6067592 DOI: 10.2147/vmrr.s66705] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Keratoconjunctivitis sicca (KCS) is a frequent canine ophthalmic disease, resulting from the deficiency of one or more elements in the precorneal tear film. There are different known causes of KCS in dogs, including congenital, metabolic, infectious, drug induced, neurogenic, radiation, iatrogenic, idiopathic, and immune mediated, though the last one is the most prevalent form in dogs. Initially, clinical signs of KCS include blepharospasm caused by ocular pain, mucoid to mucopurulent ocular discharge, and conjunctival hyperemia; secondary bacterial infection may also occur, with chronicity, corneal epithelial hyperplasia, pigmentation, neovascularization, and corneal ulceration. The diagnosis of KCS is based on the presence of consistent clinical signs and measurement of decreased aqueous tear production using the Schirmer tear test. Therapy is based on administering the following topical drugs: ocular lubricant, mucolytics, antibiotics, corticosteroids, pilocarpine, and immunomodulators. These last drugs (eg, cyclosporine, pimecrolimus, and tacrolimus) have immunosuppressive activity and stimulate tear production. Furthermore, the nerve growth factor is a new subject matter of the research. Although these therapies are advantageous, stimulation of natural tear production seems to provide the highest recovery in clinical signs and prevention of vision loss. The goal of the following article is to describe the recent developments about KCS in dogs emphasizing the use of new therapies.
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Affiliation(s)
- Pier Luigi Dodi
- Department of Veterinary Medicine Sciences, University of Parma, Parma, Italy,
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Bhatti SFM, De Risio L, Muñana K, Penderis J, Stein VM, Tipold A, Berendt M, Farquhar RG, Fischer A, Long S, Löscher W, Mandigers PJJ, Matiasek K, Pakozdy A, Patterson EE, Platt S, Podell M, Potschka H, Rusbridge C, Volk HA. International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe. BMC Vet Res 2015; 11:176. [PMID: 26316233 PMCID: PMC4552371 DOI: 10.1186/s12917-015-0464-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/29/2015] [Indexed: 12/14/2022] Open
Abstract
In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors' experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible.
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Affiliation(s)
- Sofie F M Bhatti
- Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium.
| | - Luisa De Risio
- Animal Health Trust, Lanwades Park, Kentford, Newmarket, CB8 7UU, Suffolk, United Kingdom.
| | - Karen Muñana
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 1052 William Moore Drive, Raleigh, NC, 27607, USA.
| | - Jacques Penderis
- Vet Extra Neurology, Broadleys Veterinary Hospital, Craig Leith Road, Stirling, FK7 7LE, Stirlingshire, United Kingdom.
| | - Veronika M Stein
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Bünteweg 9, 30559, Hannover, Germany.
| | - Andrea Tipold
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Bünteweg 9, 30559, Hannover, Germany.
| | - Mette Berendt
- Department of Veterinary and Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.
| | - Robyn G Farquhar
- Fernside Veterinary Centre, 205 Shenley Road, Borehamwood, SG9 0TH, Hertfordshire, United Kingdom.
| | - Andrea Fischer
- Clinical Veterinary Medicine, Ludwig-Maximillians-University, Veterinärstr. 13, 80539, Munich, Germany.
| | - Sam Long
- University of Melbourne, 250 Princes Highway, Weibee, 3015, VIC, Australia.
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559, Hannover, Germany.
| | - Paul J J Mandigers
- Department of Clinical Sciences of Companion Animals, Utrecht University, Yalelaan 108, 3583 CM, Utrecht, The Netherlands.
| | - Kaspar Matiasek
- Section of Clinical & Comparative Neuropathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Veterinärstr. 13, 80539, Munich, Germany.
| | - Akos Pakozdy
- Clinical Unit of Internal Medicine Small Animals, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.
| | - Edward E Patterson
- University of Minnesota College of Veterinary Medicine, D426 Veterinary Medical Center, 1352 Boyd Avenue, St. Paul, MN, 55108, USA.
| | - Simon Platt
- College of Veterinary Medicine, University of Georgia, 501 DW Brooks Drive, Athens, GA, 30602, USA.
| | - Michael Podell
- Chicago Veterinary Neurology and Neurosurgery, 3123 N. Clybourn Avenue, Chicago, IL, 60618, USA.
| | - Heidrun Potschka
- Department of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximillians-University, Königinstr. 16, 80539, Munich, Germany.
| | - Clare Rusbridge
- Fitzpatrick Referrals, Halfway Lane, Eashing, Godalming, GU7 2QQ, Surrey, United Kingdom.
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, GU2 7TE, Surrey, United Kingdom.
| | - Holger A Volk
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, AL9 7TA, Hertfordshire, UK.
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Charalambous M, Brodbelt D, Volk HA. Treatment in canine epilepsy--a systematic review. BMC Vet Res 2014; 10:257. [PMID: 25338624 PMCID: PMC4209066 DOI: 10.1186/s12917-014-0257-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 10/15/2014] [Indexed: 12/17/2022] Open
Abstract
Background Various antiepileptic drugs (AEDs) are used for the management of canine idiopathic epilepsy (IE). Information on their clinical efficacy remains limited. A systematic review was designed to evaluate existing evidence for the effectiveness of AEDs for presumptive canine IE. Electronic searches of PubMed and CAB Direct were carried out without date or language restrictions. Conference proceedings were also searched. Peer-reviewed full-length studies describing objectively the efficacy of AEDs in dogs with IE were included. Studies were allocated in two groups, i.e. blinded randomized clinical trials (bRCTs), non-blinded randomized clinical trials (nbRCTs) and non-randomized clinical trials (NRCTs) (group A) and uncontrolled clinical trials (UCTs) and case series (group B). Individual studies were evaluated based on the quality of evidence (study design, study group sizes, subject enrolment quality and overall risk of bias) and the outcome measures reported (in particular the proportion of dogs with ≥50% reduction in seizure frequency). Results Twenty-six studies, including two conference proceedings, reporting clinical outcomes of AEDs used for management of IE were identified. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. Only four bRCTs were identified in group A and were considered to offer higher quality of evidence among the studies. A good level of evidence supported the efficacy of oral phenobarbital and imepitoin and fair level of evidence supported the efficacy of oral potassium bromide and levetiracetam. For the remaining AEDs, favorable results were reported regarding their efficacy, but there was insufficient evidence to support their use due to lack of bRCTs. Conclusions Oral phenobarbital and imepitoin in particular, as well as potassium bromide and levetiracetam are likely to be effective for the treatment of IE. However, variations in baseline characteristics of the dogs involved, significant differences between study designs and several potential sources of bias preclude definitive recommendations. There is a need for greater numbers of adequately sized bRCTs evaluating the efficacy of AEDs for IE.
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Affiliation(s)
- Marios Charalambous
- Department of Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, Herts, UK.
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Podell M. Antiepileptic drug therapy and monitoring. Top Companion Anim Med 2014; 28:59-66. [PMID: 24070683 DOI: 10.1053/j.tcam.2013.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/20/2013] [Indexed: 11/11/2022]
Abstract
Over the past 2 decades, the number of antiepileptic drugs (AEDs) available to veterinarians has grown exponentially. Coupled with this increase is the ability to rapidly and accurately diagnose underlying brain disease with readily accessible magnetic resonance imaging. As a result, the veterinary community is attuned to the need for early treatment intervention. As more treatment choices become available, the unrelenting questions still arise are when should treatment begin, which initial drug therapy is best for our patients, when should treatment changes be considered, and finally, what are the advantages that newer drugs provide for our patients. The purpose of this chapter is to review decision-making strategies for AED therapy, provide an overview of the applicability of current AED available, and present information on the therapeutic advances in epilepsy.
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Affiliation(s)
- Michael Podell
- Chicago Veterinary Neurology and Neurosurgery, Chicago Veterinary Emergency and Specialty Center, Chicago, IL, USA.
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7
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Affiliation(s)
- James A Lavely
- Department of Neurology and Neurosurgery, VCA Animal Care Center of Sonoma, 6470 Redwood Drive, Rohnert Park, CA 94928, USA.
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9
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Seizures and Sleep Disorders. HANDBOOK OF SMALL ANIMAL PRACTICE 2008. [PMCID: PMC7152292 DOI: 10.1016/b978-1-4160-3949-5.50026-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Chang Y, Mellor DJ, Anderson TJ. Idiopathic epilepsy in dogs: owners' perspectives on management with phenobarbitone and/or potassium bromide. J Small Anim Pract 2006; 47:574-81. [PMID: 17004949 DOI: 10.1111/j.1748-5827.2006.00203.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To explore seizure management from the perspective of the owners of dogs with idiopathic epilepsy. METHODS Questionnaires were mailed to owners of 29 dogs under management for suspected or diagnosed idiopathic epilepsy through the clinics of the Small Animal Hospital of the University of Glasgow Veterinary School, using either phenobarbitone or potassium bromide alone or in combination. RESULTS The postal survey had an 86 per cent response rate. Analysis of the responses demonstrated that "the dog's quality of life", "adequate seizure frequency" and "acceptable side effects of antiepileptic drugs" were the three greatest concerns for owners; 52 per cent of owners strongly agreed that the seizure management for their dog was adequate, though the seizure frequency reported varied within this group; the majority of owners did not consider the administration of medication a nuisance. However, approximately 60 per cent of owners reported that caring for an epileptic dog had an effect on the organisation of their free time, though this was not dependent on perception of seizure control. Opinions as to the value of further diagnostic procedures, in particular intracranial imaging, were significantly affected by having pet health insurance. CLINICAL SIGNIFICANCE From the owners' perspective, adequacy of seizure control is determined by the balance between "the dog's quality of life", "adequate seizure frequency" and "acceptable side effects of antiepileptic drugs". A frequency of less than one seizure every three months is associated with the perception by owners of adequate seizure control.
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Affiliation(s)
- Y Chang
- Division of Companion Animal Science, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, 464 Bearsden Road, Bearsden, Glasgow G61 1QH
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Abstract
This article reviews anticonvulsant therapies in current use for dogs and cats and briefly describes new modes of anticonvulsant therapy that are being investigated or pending publication. Most of the information contained within the article is based on published information. Some of the information, however, is based on the author's clinical experience and is identified as such.
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Affiliation(s)
- Curtis W Dewey
- Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, NY 14853, USA.
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Govendir M, Perkins M, Malik R. Improving seizure control in dogs with refractory epilepsy using gabapentin as an adjunctive agent. Aust Vet J 2005; 83:602-8. [PMID: 16255282 DOI: 10.1111/j.1751-0813.2005.tb13269.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess whether there is a change in seizure activity in dogs with refractory epilepsy that are receiving appropriate doses of phenobarbitone and/or potassium bromide, when gabapentin is added to the therapeutic regimen. DESIGN A prospective study of 17 dogs with a refractory seizure disorder, 16 of which have idiopathic epilepsy. PROCEDURE Patients were stabilised using phenobarbitone and/or potassium bromide to produce tolerable therapeutic serum concentrations and dosed additionally with gabapentin at 35 to 50 mg/kg/d (divided twice or three times daily) for 4 months. Owners recorded seizure activity and side effects during this period in a standardised diary. Patients underwent monthly physical examinations and venepuncture to assess selected serum biochemical analytes, as well as phenobarbitone and bromide concentrations. Patients were further monitored for long-term response to adjunctive gabapentin therapy. RESULTS There was no significant decrease in the number of seizures over the study period for the entire cohort, however three dogs stopped seizuring completely. There was a significant increase in the number of patients who showed an increase in the interictal period (P > 0.001). Serum alkaline phosphatase activity and triglyceride concentrations were elevated at baseline. There were no significant changes in biochemical analytes during the course of the study period. Side effects observed initially on addition of gabapentin included sedation and hind limb ataxia. The former resolved spontaneously after a few days; the latter after a slight reduction in bromide dose. Long-term, a further two patients became seizure free and ten patients remained on gabapentin indefinitely. No long-term side effects have become apparent. CONCLUSION Addition of gabapentin to phenobarbitone and/or potassium bromide increased the interictal period and shortened the post-seizure recovery in some canine epileptics. In some dogs, seizures were prevented completely, while in others there was an increase in interictal period. The short-half life of gabapentin has advantages for seizure control, however its present high cost may prohibit therapy in large dogs.
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Affiliation(s)
- M Govendir
- Faculty of Veterinary Science, Building B14, The University of Sydney, New South Wales.
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Abstract
Epilepsy is a common neurological disorder in both dogs and humans. It is refractory to therapy in approximately one-third of canine patients, and even with the advent of new antiepileptic drugs for humans, appropriate treatment options in dogs remain limited. The pathogenesis and pathophysiology of epilepsy is being studied extensively in both human patients and rodent models of experimental epilepsy at the cellular and molecular level, but very little is known about the aetiologies of epilepsies in dogs. In this review, canine epilepsy will be discussed with reference to the human epilepsies and experimental epilepsy research. There is much work to be done in order to classify canine seizure types and breed-specific epileptic syndromes, particularly with reference to electroencephalographic abnormalities and possible genetic abnormalities. The review considers the appropriate use of antiepileptic drugs: phenobarbitone and potassium bromide are effective in most canine patients, although dosing regimes need to be carefully tailored to the individual, with serum concentration measurement. However, a significant proportion of patients remains refractory to these drugs. Work is currently underway to test the efficacy of newer antiepileptic drugs in the treatment of canine epilepsy, and preliminary data suggest that human drugs such as levetiracetam and gabapentin are of benefit in dogs with refractory epilepsy.
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Affiliation(s)
- Kate Chandler
- Royal Veterinary College, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom.
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