Nonsteroidal anti-inflammatory drugs (NSAID) like diclofenac and flunixin are freely available throughout the continent of South America, signaling a risk to the avian scavengers of the region, a new study has found.
The researchers — Kane P. J. Colston, Irene Bueno, Lucas Gelid, Juan Manuel Grande — conducted a search of veterinary pharmaceutical products registered in all 10 Spanish and Portuguese-speaking countries across South America.
“Our search revealed that both diclofenac and flunixin have been approved for use in at least one livestock or domestic animal species in all the 10 South American countries evaluated,” the authors noted.
Brazil had the highest number of different products containing diclofenac registered with 23, closely followed by 20 in Argentina. For flunixin, Colombia had the highest number of products registered with 58, again followed by Argentina with 40.
“In all countries except Chile, at least one product containing diclofenac was approved for use in bovines, ovines, caprines, equines, and porcines. In Chile, the only authorized product containing diclofenac was for topical use in equines. For flunixin, the majority of products in all countries were intended for bovines, porcines, and equines; however, products were available in all countries except Venezuela and Bolivia for other species,” the paper noted.
South America is home to at least 21 scavenging raptor species, ranging from those only consuming carrion to opportunistic scavengers. Among them are six species of New World vulture.
“Diclofenac toxicity in this family has only been assessed in the turkey vulture (Cathartes aura), which appears tolerant to the acutely toxic effects detected in Old World vultures (Rattner et al., 2008). However, no such information exists on the susceptibility of other species, such as the Andean condor. This species is classified as IUCN Vulnerable (IUCN, 2020), and current populations are in sharp decline, largely as a result of deliberate or indirect persecution through pesticide poisoning in the frame of human-wildlife conflicts (Grande et al., 2018; Plaza et al., 2019),” noted the researchers.
Information also does not exist for diclofenac’s possible effects on the king vulture (Sarcoramphus papa) or the greater yellow-headed vulture (Cathartes melambrotus), species not yet threatened but in decline, thought mostly due to habitat loss.
No evidence exists as to the toxicity of flunixin (nor other NSAIDs like nimesulide, carprofen, or ketoprofen) in New World vultures.
“Coupled with a growing livestock agricultural sector across South America, there exists an urgent need to generate scientific evidence to understand the risk of these drugs to South American avian scavengers and to establish suitable management strategies to prevent future population declines,” the authors highlighted.
Under the radar: The availability of nonsteroidal anti-inflammatory drugs in South America and implications for avian scavenger populations was published in the journal Conservation Science and Practice on March 5, 2025.