Presumed zonisamide-induced blood dyscrasias in four dogs.

OBJECTIVE: To describe 4 canine cases of presumed zonisamide-induced blood dyscrasias. CASE SUMMARY: From 2007 to 2018 at Angell Animal Medical Center and from 2014 to 2019 at the Cummings School of Veterinary Medicine at Tufts University, 4 dogs presented with febrile neutropenia while being administered zonisamide. No septic focus was found on workup for any of the dogs, and the clinical signs were attributed to an idiosyncratic drug reaction. All WBC counts returned to normal with drug withdrawal, and all dogs survived. NEW OR UNIQUE INFORMATION PROVIDED: Presumptive zonisamide-induced blood dyscrasias are a rare complication that has not previously been reported in the veterinary literature.