Antivenom should be given within an hour of snakebite

Melbourne, Oct 30 : People bitten by snakes should be given antivenom at least within an hour so that it can effectively reduce the blood thinning effects of venom, according to a new study.

In the study, led by Australian clinical toxicologist Dr Geoffrey Isbister, from the Menzies School of Health Research, researchers developed a mathematical model mimicking the action of taipan venom on the many proteins, called 'clotting factors', that contribute to blood clotting in the human body.

While it is difficult to model the complex coagulation system, Isbister said that the general predictions of the model did match up well with real data on the effects of taipan bite, reports ABC Online. They found evidence that Taipan venom neutralises the clotting factors, causing a dramatic thinning of the blood in people suffering a bite. Usually it is treated with antivenom and by giving patients fresh frozen plasma to help replace the missing clotting factors. However, the researchers were surprised when they used the model to predict the effects of antivenom, which binds to the venom and effectively removes it from the system.

"What we found with antivenom was only if you did it really early on could it prevent the whole process happening. If it's not given within 30 minutes, and definitely within an hour, then it made no difference to the time it took for the system to recover, for the clotting factors to come back to normal," said Isbister.

However the researchers claimed that the data does not challenge the effectiveness of taipan antivenom, which has been proven to effectively bind to the venom, but does question conventional wisdom about its effects.

"The thing has always been that if you give antivenom, it will shorten the course of that clotting effect. [However] the model suggests if you don't give antivenom really early, you're not going to shorten the time of that coagulopathy," said Isbister.

He further stressed that blood thinning is just one effect of taipan venom, and thus the model does not look at the effect of the antivenom on other aspects of venom toxicity.

Isbister said that they are now planning to look at real data on Australian snake bite to see if the use of antivenom is in fact reducing the blood-thinning effects of venom.

The study is published online in the journal Toxicon.

ANI