Therapeutic Aspects of Dogs with Presumptive Diagnosis of Idiopathic Epilepsy
Keywords:seizure, phenobarbital, potassium bromide, adverse effects, clinical neurology.
Background: Epilepsy is a chronic neurological condition characterised by recurrent epileptic seizures. Various antiepileptic drugs are used for the management of canine idiopathic epilepsy. Phenobarbital is the drug of choice for long-term treatment in dogs. Although it is well tolerated, phenobarbital can cause liver injury if administered alone or in combination with other drugs. Therefore, the main of this study was to identify dogs with presumptive diagnosis of idiopathic epilepsy and information about the antiepileptic drugs, the dose and frequency of administration, period of treatment, frequency of the seizure before and after start the treatment, complementary exams and adverse effects.
Materials, Methods & Results: In this study were included 21 dogs with idiopathic epilepsy. All dogs were examined and having blood taken for blood count, biochemical tests (ALT, AST, AP, total protein, albumin, creatinine, urea, amylase, lipase, cholesterol and triglycerides), measurement of serum phenobarbital and/or potassium bromide and, some dogs, free T4 by dialysis and canine TSH. In this study, it was observed monotherapy (phenobarbital) in 76.19% (16/21), double therapy (phenobarbital and potassium bromide) in 19.05% (4/21) and triple therapy (phenobarbital, potassium bromide and gabapentin) in 4.76% (1/21) of dogs. The phenobarbital was used as monotherapy with dose between 1.4 and 12 mg kg-1 and the median of serum concentration was 26.41 μg kg-1. There was significant reduction in the frequency of the seizure after start the treatment. There was refractory to antiepileptic drugs in two dogs (9.5%). In blood analysis, there was increase serum activities of AP (23.81%) and ALT (14.20%), decrease total protein (42.29%), hypoalbuminemia (9.5%) and it was not increased AST activities. The main adverse effects were nodularliver damage and hypothyroidism.
Discussion: In most cases of dogs with idiopathic epilepsy, monotherapy is preferred, because it tends to avoid complications that may arise from drug interactions and may also improve compliance by providing a simple treatment regimen. In this study, the phenobarbital controlled the seizures when used as monotherapy. It is considered success of an antiseizure drug when there is a reduction of seizure frequency by at least 50%, with minimal drug side effects. Approximately 20-30% of dogs with epilepsy do not have satisfactory seizure control or experience intolerable adverse effects with appropriate conventional medical treatment. In this study, there was refractory to antiepileptic drugs in 9.5%, one dog treated with phenobarbital and other with phenobarbital and potassium bromide. The long-term use of phenobarbital causes increase in liver enzymes, ALT and, mainly, ALP, these are attributed to enzymatic induction and to low degree of liver damage. ALT and AP increased the values and this does not necessarily indicate clinically significant liver damage or the need to stop therapy. The risk of liver toxicity appears to be greater with concentrations higher than 35 μg mL-1 or when multiple potentially hepatotoxic drugs are used. Other factors associated to the long-term use of anticonvulsant, such phenobarbital, potassium bromide or both, for the treatment of idiopathic epilepsy in dogs is acute pancreatitis and hypothyroidism. In this study, it was not observed acute pancreatitis, but there were two dogs with hypothyroidism. The long-term use of phenobarbital did not cause significant side effects, even with changes in the biochemical tests.
Andric N., Popovic N., Stepanov P., Francuski J. & Durdevic D. 2010. Biochemical changes in the blood serum of dogs treated with phenobarbital. Acta Veterinaria (Beograd). 60: 573-584.
Arrol L., Penderis J., Garosi L., Cripps P., Gutierrez-Quintana R. & Gonçalves R. 2012. Aetiology and long-term outcome of juvenile epilepsy in 136 dogs. Veterinary Record. 170(13): 335.
Berendt M., Gredal H., Ersboll A. & Alving J. 2007. Premature death, risk factors, and life patterns in dogs with epilepsy. Journal of Veterinary Internal Medicine. 21: 754-759.
Boothe D.M., Dewey C. & Carpenter D.M. 2012. Comparison of phenobarbital with bromide as a first-choice antiepileptic drug for treatment of epilepsy in dogs. Journal of American Veterinary Medicinal Association. 240: 1073-1083.
Center S.A., Elston T.H., Rowland P.H., Rosen D.K., Reitz B.L., Brunt, J.E., Roman I., House J., Bank S., Lynch L.R., Dring L.A. & Levy J.K. 1996. Fulminant hepatic failure associated with oral administration of diazepam in 11 cats. Journal of American Veterinary Medicinal Association. 209(3): 618-625.
Cornford E.M., Diep C.P. & Pardridge W.M. 1985. Blood-brain barrier transport of valproic acid. Journal of Neurochemistry. 44: 1541-1550.
Cury E.Z. 2005. Avaliação clínica, laboratorial e radiológica de filhotes de cães submetidos à terapia com fenobarbital. 102f. Curitiba, PR. Dissertação (Mestrado em Ciências Veterinárias) - Programa de Pós-graduação em Ciências Veterinárias, Universidade Federal do Paraná.
Dowling P.M. 1999. Update on therapy of canine epilepsy. Canadian Veterinary Journal. 40: 595-598.
Feldman B.F., Zinkl J.G. & Jain N.C. 2000. Schalm’s Veterinary Hematology. 5th edn. Philadelphia: Elsevier Mosby, 1344p.
Fenner W. & Hass J. 1989. Mechanisms of Seizure Disorders. Problems in Veterinary Medicine. 1(4): 501-515.
Foster S.F., Church D.B. & Watson A.D. 2000. Effects of phenobarbitone on serum biochemical tests in dogs. Australian Veterinary Journal. 78(1): 23-26.
Govendir M., Perkins M. & Malik R. 2005. Improving seizure control in dogs with refractory epilepsy using gabapentin as an adjunctive agent. Australian Veterinary Journal. 83(10): 602-608.
Heynold Y., Faissler D., Steffen F. & Jaggy A. 1997. Clinical, epidemiological and treatment results of idiopathic epilepsy in 54 labrador retrievers: a long-term study. Journal of Small Animal Practice. 38(1): 7-14.
Kluger E.K., Malik R., Ilkin W.J., Snow D., Sullivan D.R. & Govendir M. 2008. Serum triglyceride concentration in dogs with epilepsy treated with phenobarbital or with phenobarbital and bromide. Journal of American Veterinary Medicinal Association. 233: 1270-1277.
Lima J.G. & Arias M.V.B. 2012. Acompanhamento dos casos de epilepsia canina atendidos no Hospital Veterinário da Universidade Estadual de Londrina. MEDVEP - Revista Científica de Medicina Veterinária Pequenos Animais e Animais de Estimação. 10: 134-140.
Lorenz M.D., Coates J.R. & Kent M. 2011. Seizures, Narcolepsy and Cataplexy. In: Handbook of Veterinary Neurology. 5th edn. St.Louis: Elsevier/Saunders, pp.384-400.
Monteiro R., Anderson T.J., Innocent G., Evans N.P. & Penderis J. 2009. Variations in serum concentration of phenobarbitone in dogs receiving regular twice daily doses in relation to the times of administration. Veterinary Record. 165: 556-558.
Muñana K.R., Thomas W.B., Inzana KD., Nettifee-Osborne J.A., McLucas K.J., Olby NJ., Mariani C.J. & Early P.J. 2012. Evaluation of levetiracetam as adjunctive treatment for refractory canine epilepsy: a randomized, placebocontrolled, crossover trial. Journal of Veterinary Internal Medicine. 26: 341-348.
O’Brien DP. 2003. Pathogenesis of idiopathic epilepsy. In: Proceedings of 4th the American College Veterinary. Internal Medicine Annual Forum (National Harbor, USA). pp.404-406.
Packer R.M.A., Shihab N.K., Torres B.B.J. & Volk H.A. 2014. Clinical Risk Factors Associated with Anti-Epileptic Drug Responsiveness in Canine Epilepsy. Plus One. 9(8): e106026.
Podell M. 2013. Antiepileptic drug therapy and monitoring. Topics in Companion Animal Medicine. 28: 59-66.
Podell M. & Fenner W.R. 1993. Bromide therapy in refractory canine idiopathic epilepsy. Journal of Veterinary Internal Medicine. 7: 318-327.
Reynolds N.C. & Murphy J.R. 1989. Serum free levels and evaluation anticonvulsant drug interactions. Wisconsin Medical Society. 88: 25-27.
Sanders S. 2015. Antiseizure medications. In: Seizures in dogs and cats. Ames: John Wiley & Sons Inc., pp.166-220.
Thomas W.B. 2010. Idiopathic Epilepsy in Dogs and Cats. Veterinary Clinic of North America: Small Animal Practice. 40(1): 161-179.
Thomas W.B. & Dewey C.W. 2016. Seizures and Narcolepsy. In: Dewey C.W. & Da Costa R.C. (Eds). Practical guide to canine and feline neurology. Ames: JohnWiley & Sons Inc., pp.249-268.
Tipold A., Keefe T.J. Löscher W., Rundfeldt C. & de Vries F. 2015. Clinical efficacy and safety of imepitoin in comparison with phenobarbital for the control of idiopathic epilepsy in dogs. Journal of Veterinary Pharmacology and Therapeutics. 38(2): 160-168.
Xenoulis P.G., Levinski M.D., Suchodolski J.S. & Steiner J.M. 2011. Serum triglyceride concentrations in miniature schnauzers with and without a history of probable pancreatitis. Journal of Veterinary Internal Medicine. 25: 20-25.
How to Cite
This journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Such access is associated with increased readership and increased citation of an author's work. For more information on this approach, see the Public Knowledge Project and Directory of Open Access Journals.
We define open access journals as journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition of "open access" we take the right of users to "read, download, copy, distribute, print, search, or link to the full texts of these articles" as mandatory for a journal to be included in the directory.
La Red y Portal Iberoamericano de Revistas Científicas de Veterinaria de Libre Acceso reúne a las principales publicaciones científicas editadas en España, Portugal, Latino América y otros países del ámbito latino