Prospective study of zonisamide therapy for refractory idiopathic epilepsy in dogs.
OBJECTIVE
Investigation of the efficacy of zonisamide as an add-on therapy in dogs with refractory epilepsy.


METHODS
Thirteen dogs fulfilled the inclusion criteria of poor seizure control despite adequate serum levels of phenobarbital, potassium bromide or both. One further dog was treated with zonisamide as monotherapy because of severe blood dyscrasia due to phenobarbital treatment. Various seizure parameters were evaluated retrospectively for a four month period without zonisamide and prospectively for the same time period under zonisamide add-on therapy. The study time period was extended by up to 17 months to evaluate long-term outcome.


RESULTS
Data of 11 dogs could be evaluated: nine of them were responders. The median reduction of seizure frequency of all dogs on zonisamide add-on therapy was 70 per cent (range 14 to 100 per cent). Only transient central nervous system side effects were reported. No further increase of liver enzymes occurred. In three of the responder dogs, seizure control subsided after individual time periods (between 69 days and seven months).


CONCLUSIONS
In dogs with refractory epilepsy, zonisamide may have a beneficial effect on seizure control. In three responder dogs, seizure activity relapsed possibly because of an induction of tolerance. Limiting factors are the high costs.
von Klopmann
T
T
Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Bischofsholer Damm 15, 30173 Hannover, Germany.
Rambeck
B
B
Tipold
A
A
D000284:Administration, Oral; D000818:Animals; D000927:Anticonvulsants / Q000008:administration & dosage / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy* / Q000473:pathology; D004285:Dogs; D004827:Epilepsy / Q000188:drug therapy / Q000662:veterinary*; D007555:Isoxazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies; D016896:Treatment Outcome; D000078305:Zonisamide
D000927:Anticonvulsants; D007555:Isoxazoles; D000078305:Zonisamide