Cease NSAIDs 24 Hours Before Collecting Blood for Orthobiologics Use in Horses

According to veterinarians at The University of Pennsylvania, only a 24-hour “withdrawal” period is needed between administration of nonsteroidal anti-inflammatory drugs (NSAIDs) and collecting blood for processing platelet-rich plasma (PRP) or autologous protein solution (APS).^*

Both PRP and APS are classified as orthobiologics: biologic products used to help improve the quality of tissue healing, manage pain, and decrease the rate of reinjury. In horses, veterinarians use orthobiologics to help manage horses with tendon and ligament injuries, as well as osteoarthritis. These blood-based orthobiologics concentrate blood components such as leukocytes (white blood cells) and platelets, which contain cytokines and growth factors, some of which are inflammation mediators.

“Musculoskeletal injuries are often treated using a multimodal approach, and NSAIDs such as phenylbutazone or firocoxib are commonly prescribed. However, studies in human medicine suggest that there may be concerns with collecting blood samples for orthobiologics in patients that are being treated with NSAIDs,” explained Catherine Whitehouse, M.S., a Kentucky Equine Research nutritionist.

One study found no effect of a single dose of NSAID, including phenylbutazone, on cytokines or growth factors in PRP or APS. As some horses may receive NSAIDs prior to collecting blood for PRP or APS, a study was designed to determine if long-term NSAIDs affect blood products.^*

In this study, horses were administered either phenylbutazone or firocoxib by mouth for six days at doses commonly used in clinical practice. Blood was collected at baseline (before the first dose of NSAID) and again 7, 14, and 21 days after the last dose of NSAID. Blood samples were used to produce PRP and ACS using commercial kits according to the manufacturers’ directions. Concentrations of leukocytes, platelets, cytokines, and growth factors were subsequently measured at all time points in both PRP and APS.

Researchers observed differences in leukocyte and platelet concentrations in PRP compared to APS. Most notably, leukocytes were higher in APS on day 7 and platelets were higher in APS at baseline in the firocoxib group on day 0 and in the phenylbutazone group on day 7.

“The key finding in this study was that no significant difference in cytokine or growth factor concentrations was identified following the six days of NSAID therapy,” Whitehouse said.

Based on this result, the researchers stated, “Veterinarians can recommend the administration of these oral NSAIDs prior to obtaining blood for PRP and APS.” However, veterinarians should discontinue NSAIDs for 24 hours prior to collecting blood for processing PRP and APS to “avoid significant alterations in cytokine and growth factor profiles in these blood-derived products.”

Osteoarthritis is a common cause of musculoskeletal pain and disability that limits the athletic careers of horses. In addition to NSAIDs and orthobiologics, horses may also benefit from joint supplements such as those containing glucosamine, chondroitin sulfate, and hyaluronic acid.

“These ‘chondroprotective’ ingredients help to support joints in several key areas, including cartilage health, joint fluid viscosity, and a healthy immune response,” advised Whitehouse.

^*Brown, K.A., E.N. Gregorio, D. Barot, A. Usimaki, R.L. Linardi, J.R. Missanelli, Y. You, M.A. Robinson, and K.S. Ortved. 2024. Prolonged administration of oral phenylbutazone and firocoxib in horses has no impact on selected cytokine and growth factor concentrations in platelet-rich plasma and autologous protein solution. American Journal of Veterinary Research: doi: 10.2460/ajvr.24.04.0098.