Drug is Useful in Treating Pesticide Poisoning
(Beyond Pesticides, August 9, 2006) A new study, An Effective Counter Measure Against Poisoning by Organophosphorus Insecticides and Nerve Agents from the University of Maryland School of Medicine showed findings when treatment with galantamine, a drug used to treat mild to moderate cases of Alzheimer’s is combined with atrophine it can protect people from the toxic effects of nerve agents and some insecticides. In the study researchers gave guinea pigs a treatment of galantamine, combined with atrophine, which protected them from lethal doses of the nerve agents sarin and somain and one of the most extremely acute toxic insecticides parathion, which is notorious for the number and severity of human poisonings that it causes each year.
Study results find that galantamine, a drug originally extracted from snowdrop flowers currently approved to treat Alzheimer’s disease, could be used as an antidotal therapy to counteract the lethal effects of even the most deadly organophosphorus compounds. According to the findings that will be published later this week in the online edition of the Proceedings of the National Academy of Sciences, the study provides the basis for the further development of a safe and effective treatment to protect people exposed to organophosphorus compounds, that include nerve agents that have been used in chemical warfare and terrorist attacks, as well as pesticides used in and around households and on farms worldwide has been provided in the findings that has been published this week in the online edition of the Proceedings of the National Academy of Sciences.
According to the lead author of the study, Dr. Edison X. Albuquerque, “the only medication currently approved by the Food and Drug Administration to prevent the catastrophic effects of nerve agent poisoning does not protect the brain," Dr. Albuquerque continued, "This medication, pyridostigmine, doesn't effectively cross the blood-brain barrier."
Most animals that are treated with pyridostigmine and exposed to toxic doses of nerve agents survive when they receive a combination of other medications, including atropine, oximes and benzodiazepines. However, even with this drug cocktail, animals surviving the initial nerve agent exposure can develop neurological effects.
The reason Dr. Albuquerque and his colleagues studied the effects of galantamine in an animal model was to counteract the neurological devastation caused by nerve agents and organophosphorus pesticides. According to Dr. Albuquerque, "We wanted to test a drug with neuroprotective properties that is widely available and safe and could be as effective taken before as it would be taken after an exposure." Dr. Albuquerque continued, "galantamine fit that description."
According to the study, those animals treated with galantamine and later exposed to lethal doses of soman or sarin survived and showed no signs of the most common symptoms of exposure to nerve agents, such as convulsions, respiratory distress and loss of coordinated movement. Comparatively, those animals treated with the standard therapy of atropine and benzodiazepines all died after being exposed. The researchers repeated the experiments with paraoxon, the active metabolite of the insecticide parathion and again, all of the animals survived with no signs of toxicity.
Due to the difficulty in predicting when a person might be exposed to toxic levels of nerve agents or insecticides, the researchers also studied whether treatment with galantamine following exposure could counteract their toxicity effectively. According to Dr. Albuquerque, "All the animals treated with the antidotal therapy consisting of galantamine and atropine within five minutes after an exposure to lethal doses of soman and paraoxon survived with no side effects.”
Dr Albuqurque said, “The basic finding of their study is that galantamine effectively penetrates the blood-brain barrier and protects the brain from the toxic effects of organophosphorus compounds, as long as it is administered before or soon after an exposure. " The researchers feel that this simple and safe antidotal therapy could be added to the arsenal of medications carried by all military members and first responders, who could easily administer it to themselves should they suspect that they've been exposed to a nerve agent. The researchers also feel that their findings show that this therapy could be used worldwide to save the lives of people who come in contact with toxic levels of organophosphorus insecticides.
Other researchers such as David H. Moore, D.V.M., Ph.D., director of Strategic Research Program Development at the U.S. Army Medical Research Institute of Chemical Defense say that, "These important findings of Dr. Albuquerque and his colleagues will pave the way for further improvements in the current medical countermeasures against intoxication by organophosphorus nerve agents and insecticides."