A type of rat poison, which is illegal in the United States, has the potential to be used in an intentional mass poisoning or as a terrorist weapon, according to study findings published in the current issue of the Annals of Emergency Medicine.

“Imported pesticides represent a special public health risk in large urban areas with significant immigrant populations whose members may have used these substances successfully as rodenticides in their countries of origin,” lead author Dr. K. Scott Whitlow, currently with VCU Health System/MCV/VA Poison Center in Richmond, Virginia, and his associates indicate.

The substance, called tetramethylenedisulfotetramine, is a highly lethal, neurotoxic poison that has been used many times in large mass poisonings in China, as recently as 2004.

The one documented case in the U.S. of accidental poisoning with this agent in 2002 highlights the fact that it is still available and may be imported.

As little as 7 to 10 milligrams of the odorless, tasteless, water-soluble substance can be lethal in humans, the authors note. Mild to moderate poisoning is associated with headache, dizziness, nausea, Vomiting, numbness around the mouth and weakness. Severe intoxication can produce very rapid or irregular heart beat, seizures and coma. Symptom onset may be delayed for up to 13 hours,

There is no specific antidote for tetramethylenedisulfotetramine poisoning, Whitlow’s team points out, and treatment is “mainly supportive.” They recommend large doses of sedatives or tranquilizers for continuously seizing patients, as well as intubation other supportive measures.

Tetramethylenedisulfotetramine poisoning should be considered in diagnosing any patient with unexplained seizures, or other signs and symptoms consistent with exposure to this agent, if there are no other reasonable explanations for the illness, the authors advise.

Prompt recognition of suspected cases could “prevent more widespread exposures,” they conclude, “in addition to preventing an intentional mass poisoning or terrorist event.”

SOURCE: Annals of Emergency Medicine, June 2005.