European scientists call the definitive ban of veterinary diclofenac

    The request, published in a letter in Science, comes from the case of a cinereous vulture poisoned by exposure to diclofenac in Catalonia, the first case of poisoning by this drug for veterinary use in Spain and in Europe confirmed in vultures.

    Despite the strong and unchallenged evidence that the well-documented catastrophic vulture declines across South Asia in the 1990s were caused by veterinary use of the non-steroidal anti-inflammatory drug (NSAID) diclofenac, the drug was still approved for veterinary use in Spain in 2013. Approval was given despite strong warnings that there could be impacts on European vulture populations.

    According to a study published in 2016, diclofenac use in livestock could contribute an additional annual mortality rate of 0.9% to 7.7% in Spanish griffon vultures (Gyps fulvus). However, it was argued by regulatory authorities in the European Union and Spain (and some other European countries) that diclofenac would not enter the vulture food supply, because of tight restrictions on the provisioning of vulture feeding sites with carcasses of animals that had received veterinary drugs before they died. However, even at the time approval for diclofenac was given, this argument was already known to be false.

    A recently published paper documents the death of a fledgling cinereous vulture (Aegypius monachus) found in a nest in Catalonia, Spain, in September 2020 Chemical analysis of its tissues and post-mortem findings clearly showed that it died from exposure to veterinary diclofenac, a NSAID that is highly toxic to vultures.

    This case is the first confirmed case of diclofenac poisoning in Spain (and in Europe), and is also the first report of diclofenac poisoning in cinereous vultures, which confirms the very real threat that diclofenac poses if it remains in veterinary use (Photo: Agents Rurals de Catalunya).

    Previously, four Eurasian griffon vultures were poisoned by flunixin, and the monitoring animal carcasses available to vultures in Spain showed that some carcasses contained residues of three veterinary NSAIDs, including diclofenac and flunixin, both of which are known to be toxic to vultures.

    The evidence that regulations intended to control the method of disposal of carcasses do not protect vultures from exposure to toxic drugs is now overwhelming. According to Antoni Margalida, scientist at the Research Group in Game Resources and Wildlife Management of the Instituto de Investigación en Recursos Cinegéticos (IREC – CSIC, UCLM, JCCM) and leading of the letter published in Science, “the case of diclofenac poisoning in Spain represents a watershed moment that proves that veterinary diclofenac not only enters the food supply of vultures in Spain, but also kills them. Diclofenac should be banned from veterinary use in Europe and the licenses of other vulture-toxic NSAIDs require urgent review”.

    Rhys Green, chairman of SAVE (Save Asian Vultures from Extinction) and professor at Cambridge University, coauthor of the letter in Science, says that “the threat posed by diclofenac and other toxic NSAIDs was obvious before, but this latest published evidence should convince regulators that veterinary protocols and directives are inadequate. The only way to prevent harm to legally protected populations of wild vultures is to rescind licenses in Europe for the production of veterinary diclofenac and other NSAIDs toxic to vultures. Where necessary, other veterinary drugs known to be safe for vultures, such as meloxicam, should be used instead“.

    This request is also in line with the recent Convention of Migratory Species resolution, which among key steps needed for toxic NSAIDs called for an international effort to remove diclofenac from veterinary practice.

    The scientific publication of this research is available at: