Another veterinary drug, nimesulide, confirmed toxic to vultures

Photo Chris Bowden – RSPB

A paper published in the current issue of Science of the Total Environment (here) confirms that the non-steroidal anti-inflammatory drug (NSAID), nimesulide, is toxic to vultures, following safety testing of the drug on vultures in South Africa.

Since the banning of veterinary diclofenac, the NSAID which drove three species of Gyps vultures to near-extinction in South Asia, there has been an urgent need to test other NSAIDs also available on the market for veterinary use, and which are suspected to also be toxic to vultures. One such drug which is becoming increasingly popular especially in India was nimesulide. The drug was already implicated in the deaths of several vultures in NW India, which showed signs of NSAID poisoning, i.e. visceral gout, coupled with nimesulide residues in the blood (here and here). Now, these published results  confirm that nimesulide is, indeed, highly toxic to vultures.

In a safety testing experiment carried out in South Africa, in which two Cape Griffon Vultures G. coprotheres were given nimesulide, both birds developed increased concentrations of uric acid in the blood and visceral gout, symptoms of kidney failure, and as with diclofenac poisoning, they died within two days of dosing. Double the recommended dose was given to the birds to replicate the common practice in India, where farmers regularly give such large doses of drugs to their injured cattle. Safety testing has been widely conducted to test the toxicity of drugs to birds, and was instrumental in proving the toxicity of diclofenac, which led to its subsequent ban. To avoid too many birds being exposed to a potentially harmful drug, only two birds are given a dose of a drug in the initial phase of the experiment, and if at least one of these birds die then the experiment is stopped and the drug declared toxic. Both birds in this latest experiment were residents of the VulPro Rehabilitation Centre, located outside Pretoria, South Africa, due to injuries that prevented them from ever being released.


Photo Chris Bowden – RSPB

Senior Conservation Scientist at the Royal Society for the Protection of Birds (RSPB, Birdlife UK), Dr John Mallord, one of the authors of the recent study, said “The results of this study are incredibly important, confirming what we have suspected for a number of years, that nimesulide can kill vultures”.

Prof. Rhys Green from the University of Cambridge and another co-author added, “The government of India previously acted quickly to ban diclofenac, which prevented vultures from going extinct. Now that we have this evidence of nimesulide’s toxicity, we call upon the Government of India to take urgent steps to ban this drug for veterinary use, to support the ongoing recovery of vulture populations in India and elsewhere in South Asia”.

Bivash Pandav, Director of the Bombay Natural History Society (BirdLife in India) said “India set an important example by banning veterinary diclofenac in 2006, but unless this work prompts similar action for nimesulide, there is a risk that those earlier efforts will have been for nothing. Especially now we know that there are at least two safe alternative drugs available for the vets: meloxicam and tolfenamic acid, there is really no reason to allow such dangerous drugs to be used.

Vinny Naidoo, Dean of Pretoria University and expert veterinary pharmacologist, who led the work said “It is tragic that this work is being driven by conservationists and not by the pharmaceutical industry itself. Hopefully the drug regulators respond quickly, as they did in India for diclofenac as it will save huge numbers of vultures”

Photo Bombay Natural History Society

This topic was highlighted at the recent annual SAVE meeting, and it was agreed that nimesulide, along with aceclofenac and ketoprofen where the published toxicity evidence is also overwhelmingly clear, and immediate bans of all three veterinary drugs have become the highest single priority for conserving Asia’s vultures.

Further links:  

Cattle drug poses deadly new threat to vultures in Science

Cuthbert et al. 2015 Pharmacy survey paper in Oryx here

John Mallord’s online talk (14th talk) at the Dec 2021 SAVE meeting

NSAID Alert summary information for each NSAID here

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