A drug, known for heavy-metal poisoning, may also be used as a treatment against snakebites.
Snakebite envenoming causes 138,000 deaths annually, and around 400,000 victims face permanent disabilities. The only treatment currently available for snakebites, antivenom, is relatively expensive and must be delivered in clinical settings due to the high rates of adverse reactions. However, snakebites typically occur in remote locations, which is why many victims have to travel for long periods of time before receiving the care they need. Nicholas Casewell, a biomedical scientist at the Liverpool School of Tropical Medicine in England, and his colleagues wanted to find something that would be easy to administer and could counteract some of the most dangerous venom toxins, snake venom metalloproteinases. These toxins cause immense bleeding and tissue damage around the bite site, but they rely on zinc ions to function. Researchers discovered that a drug called unithiol was able to collect loose metal ions to deprive the toxins of zinc.
The researchers administered a liquid form of unithiol to mice 15 minutes after viper venom was injected into their systems. This delayed the death of mice compared to the mice that did not receive the drugs. This administration worked just as well as an antivenom treatment and worked even better when they were paired together. Unithiol was also able to prevent tissue damage at the site of the venom injection, which suggests that this drug could also prevent the disabilities caused by the venom.
Leslie Boyer, a clinical researcher who studies envenomation treatment at the University of Arizona in Tucson, says, “This is an old drug, and it’s an old concept that’s finally being put to the test.” But she believes that the results seen in mice aren’t the same as tests in humans. Casewell adds that if the treatment does work on people, it may delay the effects before some serious symptoms occur. The researchers tend to run a safety trial in sub-Saharan Africa, where viper bites are a common occurrence, before giving the pill to actual snakebite victims.
Casewell states that this drug, even if it is successful in helping snakebite victims, will not be useful for bites from cobras, especially since their toxins target nerves instead of blood. He thinks that this pill can pair with other drugs that can inhibit more major toxins, hopefully creating one universal pill.
