Disease modifying treatment for feline rheumatoid arthritis.

Feline erosive polyarthritis includes the more common periosteal proliferative polyarthritis (PPP) and the rarely seen rheumatoid arthritis (RA) (11). During the past three years, 12 patients with definite feline rheumatoid arthritis, which did not respond well to conventional therapy, were treated with 7.5 mg of Methotrexate and 70 mg Leflunomide, given weekly by the oral route. The average age of the cats was 5.9 years (range 2.5 to 10 years). Siamese cats were over represented. Seven of the 12 (58%) cats showed a marked improvement, usually within four weeks. Once maximum improvement was obtained the dosage was decreased. Serious toxicity was not noted and carcinogenetic effect was not seen during the course of this study.