Topical administration of antiparalytics using a nasal spray could dramatically reduce the number of global fatalities from venomous snakebites.
Researchers at The California Academy of Sciences (CAS; San Francisco, USA) and the University of California, San Francisco (UCSF; USA) have developed an inexpensive, heat-stable, needle-free device that delivers aerosolized neostigmine to reverse paralysis. Since anticholinesterases are used as reversal agents for nondepolarizing curare-derived neuromuscular blocking agents, and are recommended in virtually all cases of neurotoxic snake envenomation, the researchers hypothesized that a topically applied anticholinesterase might also have utility in the early treatment of snakebite.
The researchers then used a continuous infusion of mivacurium—a short-duration nondepolarizing neuromuscular blocking agent—to induce neuromuscular blockade in a volunteer, successfully mimicking important elements of paralysis from snakebite neurotoxicity, including progressive bulbar deficits and neck and respiratory muscle weakness. A subsequent single application of atomized 6% neostigmine quickly improved the clinical measures of neuromuscular blockade. The study was published early online on July 24, 2013, in Clinical Case Reports.
“In addition to being an occupational hazard for field scientists, snakebite is a leading cause of accidental death in the developing world, especially among otherwise healthy young people,” said lead author Matt Lewin, PhD, director of the center for exploration and travel health at the CAS. “We are trying to change the way people think about this ancient scourge and persistent modern tragedy by developing an inexpensive, heat stable, easy-to-use treatment that will at least buy people enough time to get to the hospital for further treatment.”
Snakebite causes numerous fatalities, comparable to that of AIDS in some developing countries. Predominantly killing young and otherwise healthy individuals, the neurotoxins paralyze victims, resulting in death by respiratory failure. There is currently little funding to devise new approaches to address this problem, with more than 75% of patients who die from snakebite not surviving to receive treatment.
California Academy of Sciences
University of California, San Francisco