Miscellaneous anticonvulsant drugs
Several relatively new anticonvulsants used for seizure disorders in people have been suggested as potential alternatives
in dogs. These drugs include lamotrigine, oxcarbazepine, tiagabine, and topiramate. Information about using these drugs in
dogs with seizure disorders is limited to nonexistent. However, given the drugs' short half-lives in dogs and their expense,
they will probably not prove useful in dogs. In addition to having a half-life in dogs of only two or three hours, lamotrigine
undergoes significant hepatic metabolism in this species to a potentially cardiotoxic compound.10 Oxcarbazepine is thought to induce its own hepatic metabolism in dogs and has been demonstrated to have only a one-hour half-life
after eight days of repeated oral dosing.38 Tiagabine has a half-life of about two hours in dogs and causes marked sedation and visual impairment in dogs at relatively
low doses.39 The half-life of topiramate in dogs is only two to four hours.40
Curtis W. Dewey, DVM, MS, DACVIM (neurology), DACVS
Georgina Barone, DVM, DACVIM (neurology)
Kerry Smith, DVM
Department of Neurology and Neurosurgery
Long Island Veterinary Specialists
163 S. Service Road
Plainview, NY 11803
Gregg D. Kortz, DVM, DACVIM (neurology)
California Veterinary Neurology and Neurosurgery Specialists
1100 Atlantic St.
Roseville, CA 95678
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7. Scherkl, R. et al.: Clorazepate in dogs: Tolerance to the anticonvulsant effect and signs of physical dependence. Epilepsy
Res. 3 (2):144-150; 1989.
8. Podell, M.: Antiepileptic drug therapy. Clin. Tech. Small Anim. Pract. 13 (3):185-192; 1998.
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10. Sisson, A.: Current experiences with anticonvulsants in dogs and cats. Proc. ACVIM, ACVIM, Lake Buena Vista, Fla., 1997;
pp 596-598.
11. Rho, J.M. et al.: Mechanism of action of the anticonvulsant felbamate: Opposing effects on N-methyl-D-aspartate and gamma-aminobutyric
acidA receptors. Ann. Neurol. 35 (2):229-234; 1994.
12. Yang, J.T. et al.: Felbamate metabolism in the rat, rabbit, and dog. Drug Metab. Dispos. 19 (6):1126-1134; 1991.
13. Adusumalli, V.E. et al.: Pharmacokinetics of felbamate in pediatric and adult beagle dogs. Epilepsia 33 (5):955-960; 1992.
14. Yang, J.T. et al.: Felbamate metabolism in pediatric and adult beagle dogs. Drug Metab. Dispos. 20 (1):84-88; 1992.
15. McGee, J.H. et al.: Acute, subchronic, and chronic toxicity studies with felbamate, 2-phenyl-1,3-propanediol dicarbamate.
Toxicol. Sci. 45 (2):225-232; 1998.
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