UK researchers help discover blood-thinning drug neutralises cobra venom bites

A drug commonly prescribed to thin blood can be repurposed as a cheap antidote to cobra venom, researchers have found.

A team of scientists based in Liverpool, Australia, Canada and Costa Rica have discovered the drug heparin can be repurposed as an inexpensive treatment for bites.

Research has found it “drastically” reduces the number of injuries caused by cobra venom, according to the findings.

Cobras kill thousands of people a year, and around 100,000 suffer the death of body tissue and cells caused by the venom, which can lead to amputation, experts suggest.

Current antivenom treatment is expensive and does not effectively treat the necrosis of the flesh where the bite occurs.

Once herapin undergoes human trials, researchers hope it could be rolled out relatively quickly "to become a cheap, safe and effective" drug for treating bites.

Professor Greg Neely, a corresponding author of the study from the Charles Perkins Centre and Faculty of Science at the University of Sydney, said: “Our discovery could drastically reduce the terrible injuries from necrosis caused by cobra bites – and it might also slow the venom, which could improve survival rates.”

Using the gene-editing technology Crispr to identify ways to block cobra venom, scientists repurposed heparin and related drugs and showed they can stop the necrosis caused by cobra bites.

Joint corresponding author Professor Nicholas Casewell, head of the Centre for Snakebite Research and Interventions at Liverpool School of Tropical Medicine, said: “Snakebites remain the deadliest of the neglected tropical diseases, with its burden landing overwhelmingly on rural communities in low- and middle-income countries.

“Our findings are exciting because current antivenoms are largely ineffective against severe local envenoming, which involves painful progressive swelling, blistering and/or tissue necrosis around the bite site.

“This can lead to loss of limb function, amputation and lifelong disability.”

The researchers found that, unlike current antivenoms for cobra bites, which are 19th century technologies, the heparin drugs (herparinoids) act as a decoy antidote.

By flooding the bite site with decoy heparin, the antidote can bind to and neutralise the toxins within the venom that cause tissue damage.

The World Health Organisation has identified snakebite as a priority in its programme for tackling neglected tropical diseases, and announced a goal of reducing the global burden of snakebite in half by 2030.

Prof Neely said: “That target is just five years away now. We hope that the new cobra antidote we found can assist in the global fight to reduce death and injury from snakebite in some of the world’s poorest communities.”

The research, from scientists based in Australia, Canada, Costa Rica and the UK, is published in the Science Translational Medicine journal.

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