Effects of oral administration of meloxicam, carprofen, and a nutraceutical on thyroid function in dogs with osteoarthritis.

The purpose of this study was to evaluate the effect of the administration of meloxicam; carprofen; and a slow-acting disease modifying osteoarthritis agent, that contains chondroitin sulfate, purified glucosamine, and manganese ascorbate (CS-G-M), on thyroid function in dogs. Forty-six healthy (except for osteoarthritis) euthyroid dogs were blindly assigned to 3 treatment groups: meloxicam, carprofen, and CS-G-M. Each group received the recommended dose of the drug for 60 days. Sixteen other osteoarthritic euthyroid dogs, which received a placebo, were used as a control group to validate the study. For all groups, blood samples were collected on days 0, 30, and 60 to evaluate the serum total and free thyroxine, and endogenous thyrotropin concentrations. There were no significant differences among the treatment groups at each time or within each group over a 60-day period for all parameters. Moreover, none of these values were within the hypothyroid range. Based on the results of this study, the administration of meloxicam, carprofen, and CS-G-M did not affect canine thyroid function evaluation.