Study: New antidote may prevent toxic effects of cyanide

WASHINGTON — First responders may soon have a new tool to prevent the toxic effects of cyanide. According to a study published in the scientific journal Annals of Emergency Medicine, a natural form of the B12 vitamin called hydroxocobalamin may prove to be an antidote for cyanide poisoning.

“In 2005, more than 3,000 people died in fires with another nearly 14,000 injured; the majority of fire deaths are attributed to smoke inhalation or toxic gases,” said Dr. Stephen W. Borron of The University of Texas Health Science Center in San Antonio. “Until now, safe and effective treatments for cyanide poisoning associated with fire, terrorist attacks and industrial accidents have been elusive. This new therapy is an important step toward stopping that killer.”

The benefits of the compound were studied from 1987 to 1994 but only came into the world view during the aftermath of the Sept. 11 attacks at the World Trade Center. During the study, researchers found that treating patients both with smoke inhalation and diagnosed cyanide poisoning had an increased chance of survival.

The study, conducted in Paris, used fire victims who were initially treated by members of the city’s fire brigade, whose ranks included prehospital care staff. Patients were eligible for the study if they were older than 15, had soot in the mouth and nose and had an altered mental status. During the study, hydroxocobalamin was administered intravenously over 15 to 30 minutes, with additional dosing at the discretion of the treating physician.

Seventy-two percent of those treated survived. Of those patients who were diagnosed as having cyanide poisoning when admitted to the ICU, 67 percent survived the toxic chemical.

“Hydrogen cyanide contributes significantly to smoke-inhalation deaths and injuries and is the most common cause of acute cyanide poisoning in developed countries,” said lead study author Frederic J. Baud, MD, of the University of Paris. “It is very difficult to tell immediately if someone has cyanide poisoning from smoke inhalation; at the same time, early intervention can be lifesaving. Unlike some cyanide antidotes … the natural form of B12 can be used to treat patients without significant risk of harm.”