Dipyrone has been used for both fever reduction and pain relief in the horse, but has not yet gained FDA approval for use in horses. A current research project had as its objective to evaluate both the safety and efficacy of dipyrone to control fever in horses under field conditions. A total of 138 horses were enrolled in the study, requiring that they have a rectal temperature of > 102.0 degrees F, and these horses were placed randomly into two groups at a 3:1 ratio of dipyrone treated:placebo. Positive response to dipyrone was defined as a decrease in temperature of > 2 degrees or a temp of < 101.e degrees F 6 hours after the dipyrone was given (30 mg/kg IV). 76/99 dipyrone treated horses and 6/31 placebo horses responded positively. Post-treatment side effects were mild and transient, with no notable adverse GI effects. The authors concluded that dipyrone was effective in controlling fever 6 hours after it was given in 77% of the treated horses, with these treated horses having been diagnosed a wide variety of common infections. They also noted that dipyrone seemed to be safe and well tolerated by the horse.
Relevance: It was noted by the authors that KindredBio supported this study and that this company is currently seeking FDA approval of dipyrone for use in horses. The possibility of another readily available drug that can effectively control fever in horses with minimal side effects seems to me to be a very good thing.
Article: Sundman, E., Yin M, Hu, T., and Pooole, M. Double-Blind, Placebo-Controlled, Randomized Study of Dipyrone as a Treatment for Pyrexia in Horses. AAEP Proc. vol. 62, 2016, pp. 228-229.