A drug that interferes with the pumping action of lymphatic vessels could be useful for treating snakebite, reports a study published online this week in Nature Medicine. By delaying transit of the snakebite toxin through the lymphatic system, this drug could give snakebite victims more time to obtain medical care.
Each year, snakebite accounts for an estimated 100,000 deaths and 400,000 amputations worldwide. Many snake venoms contain large toxin molecules that can gain access to the blood only by being transported from the site of the bite through lymphatic vessels.
Dirk van Helden and his colleagues found that when rats were injected with snake venom, their survival time increased by 50% if they received an ointment containing glyceryl trinitrate, which is used for the treatment of heart failure. As the ointment slowed down the transport of the venom in the lymphatic system of the rats, the authors applied this ointment to healthy human volunteers together with a radiolabeled tracer. They found that the tracer’s transport was similarly slowed down within the lymphatic system of people. The authors conclude that using this ointment, survival times in humans receiving a fatal venom dose may also increase by 50%, giving victims more time to obtain medical help.