Immune-mediated polyarthritis and anterior uveitis secondary to zonisamide administration in a dog with refractory epilepsy

Abstract

The objective of this article is to describe a case of suspected zonisamide-induced immune-mediated polyarthritis (IMPA) and anterior uveitis in a dog. A 7-year-old male neutered Siberian Husky with a history of refractory idiopathic epilepsy was presented for cluster seizures. Following the addition of zonisamide to the antiepileptic regime, the dog developed new IMPA and anterior uveitis. Within a few weeks of discontinuation of the zonisamide, the dog's IMPA and anterior uveitis resolved. These immune-mediated conditions were thus presumed to be an idiosyncratic reaction to zonisamide. To our knowledge, this is the first report of IMPA and anterior uveitis in dogs associated with zonisamide administration at its recommended dose.

Keywords: adverse reactions; epilepsy; polyarthritis; uveitis; zonisamide.

FIGURE 1

Classifications of sulphonamide drugs focussing specifically on Sulfonylarylamine, Non‐Sulfonylarylamine and Sulfonamide Moiety. Sulfonylarylamine class include antibiotics. Non‐Sulfonylarylamine class includes loop diuretics and carbonic anhydrase inhibitors. Sulfonamide Moiety class includes antiepileptics (Ghimire et al., ; Madisson et al., ; Ovung & Bhattacharyya, ; Verdel et al., 2006).

FIGURE 2

Classification of sulphonamide drugs and structural differences between the classes with focus on sulphonamide structure. Purple circle denotes position of sulphonamide structure in each class. (a) Sulfonylarylamines: In this group of drugs, which includes sulphadiazine, the sulphonamide chemical structure is attached directly to the benzene ring via an amine group (‐NH2) at the N4 position. (b) Non‐sulfonylarylamines: The drugs in this class feature a sulphonamide chemical structure attached to a benzene ring with amine group attached to the cyclic structure, rather in the N4 position. An example of a drug in this class is furosemide. (c) Sulfonamide moiety: Zonisamide, like other drugs in this class, features a sulphonamide chemical structure that is not connected directly to any cyclic structure (Ghimire et al., ; Madisson et al., ; Ovung & Bhattacharyya, ; Verdel et al., 2006).