The long-term use of non-steroidal anti-inflammatory agents in geriatric dogs with osteoarthritis has not been well studied in veterinary medicine. This study evaluated the effects of firocoxib administered to dogs over 7 years of age for 90 days. Pain and lameness scores were evaluated by the owner weekly for the 1st month and then biweekly through to the end of the study, the veterinarian evaluated the dogs monthly. Serum chemistry, including urea, creatinine, alanine transferase, aspartate transaminase, bile acids and bilirubin, urine specific gravity and a urine dipstick, were performed at monthly intervals. Forty-five dogs were enrolled into the treatment group and 9 into the control group. A total of 33 dogs completed the trial in the treatment group and 8 in the control group. Lameness and pain scores were found to be significantly lower in the treated group from day 30 for most parameters evaluated. Bile acids (although not comparable to controls, with higher mean value and a high standard deviation in the control group; in addition the control
group had increased bile acids at day 0) and urea (within normal reference range provided (WNL)) were significantly different in the treatment group between days 0 and 90. Urea(WNL) on days 30 and 90 and creatinine (WNL) on day 90 were significantly different between the control group and the treatment group. The most common adverse events reported were diarrhoea, vomition, dark faeces and anorexia. This study showed that firocoxib was effective in managing pain associated with osteoarthritis for 90 days. Despite the geriatric high-risk population used for this study, minimal biochemical changes were seen and adverse drug events seen were in agreement with those previously reported.