When a scorpion stings someone in the most serious of cases, its venom acts as a nerve poison.
Severe pain throbs at the sting site and sometimes spreads. The venom causes extreme nausea, violent vomiting, slurred speech and blurred vision. And in children _ the most common victims _ the venom triggers nerves that cause their entire bodies to twitch and jerk, their eyes to roll around in their heads, and their breathing to become labored.
That all stops with the injection of a Mexican-made anti-venom that was just approved by the FDA, the first time the federal agency has approved a treatment for scorpion stings.
"This is historic," Leslie Boyer, director of the Venom Immunochemistry, Pharmacology and Emergency Response Institute at the University of Arizona in Tucson, said Thursday.
Arizona accounts for the majority of scorpion stings in the U.S., with 8,000 to 12,000 every year. Southern Nevada and western New Mexico also see them.
Boyer said researchers tested the drug, known as Anascorp, on 2,000 people at 26 hospitals in Arizona and one in Las Vegas. The results were dramatic, with children's symptoms disappearing within hours, she said.
Without the anti-venom, children experiencing extreme symptoms from a scorpion sting would have to be admitted to an intensive-care unit, be heavily sedated and put on a breathing tube _ a method that can be risky and painful.
Boyer said the FDA's approval of Anascorp couldn't come at a better time.
Until 2004, scorpion stings could be treated with an anti-venom that caused sometimes serious side effects and was not approved by the FDA. But since it had been used for nearly 50 years, Boyer said the FDA had grandfathered it in and allowed hospitals to use it because it was effective.
The anti-venom ran out in 2004 because the woman who made it retired in 1999, leaving enough to last only another five years.
Boyer, who knew how dire the situation was, traveled to Cuernavaca, Mexico, in 1999 to meet with researchers at the National Autonomous University of Mexico who were investigating the effects of a new anti-venom made by Mexico City-based Instituto Bioclon.
Scorpion stings are rampant in Mexico. The country sees 1,000 times more stings than the U.S., Boyer said.
Boyer said that immediately, she saw the potential for the anti-venom in the U.S. and got a grant from the FDA to conduct a study of the drug, which allowed hospitals to administer the new anti-venom just after the old one ran out.
"We timed it perfectly," Boyer said. "We never had to find out what would have happened if all rural Arizona was left without an anti-venom.
"We strongly believe, based on history, that we would have had deaths had we not started this project in 2004."
University of Arizona says the anti-venom has attracted attention from other countries with scorpions, including Morocco.
Dawn Bray, who lives in a small rural community near Globe in central Arizona, told The Arizona Republic that her 2-year-old son, Dally Bray, died within three hours of being stung by a scorpion in 2002. Five years later, her 5-year-old son, Morgan Bray, was stung.
Dawn Bray said she tried to stay calm as she rushed Morgan to the nearest rural hospital.
"As we are driving to the hospital, he said, `Mommy, can you drive faster because I don't want to die like Dally,'" Bray recalled.
Bray made it to a Globe hospital, and Morgan survived after being taken by helicopter to a Tucson hospital and getting the anti-venom.
"Today, I have a lot of joy and elation," Bray said after learning of the FDA approval.
Follow Amanda Lee Myers on Twitter at http://twitter.com/#!/AmandaLeeAP.