Management of OP Poisoning

The management of OP poisoning has been reviewed. Management of OP poisoning involves symptomatic treatment and the use of antidotes, especially atropine. Hypoxia, hypotension, cardiac arrhythmias and fluid balance and electrolytes may require attention. 

Worldwide mortality, studies report mortality rales of 3-25%. The compounds involved most frequently are maiathion, dichlorvos, trichlorfon, and fenthion/ malathion. Mortality rates depend on the type of compound u.sed, amount ingested, general health of the patient, delay in discovery and transport, insufficient respiratory management. delay in intubation, and failure to wean off ventilatory support. Signs and symptoms of OP poisoning can be divided into three broad categories, including muscarinic effects, nicotinic effects, and CNS effects. Complications include respiratory distress, seizures, and aspiration pneumonia. Respiratory failure is the most common cause of death. 

Oximes Oximes are compounds capable of reactivating, in some cases the complex formed by the OP compounds and acetylcholinesterase. Chemically, oximes are mono or bispyridinium compounds which can bind to the OP-AChE complex and cause the nerve agent molecule to separate from the enzyme. Importantly, oximes can reverse the actions of OP at both muscarinic and nicotinic receptors. Thus, unlike atropine, they act at the neuromuscular junction and can thus reduce the degree of paralysis. They have been shown to be effective in the management of OP pesticide poisoning. However, their effectiveness against nerve... 

Eddleston, M., Buckley, N.A., Eyer, P., Dawson, A.H. (2008b). Management of acute OP pesticide poisoning. Lancet 371 597-607. 

The clinical experience with the use of 2-PAM iodide, given with atropine and diazepam, in the treatment of the victims of Tokyo sarin attack in 1995 was very favorable (Sidell et al., 2009). However, 2-PAM should not be recommended as the drug of choice for the management of poisoning with all OPs due to its lack of efficacy against tabun and soman. 

PYRIDINIUM OXIMES IN MANAGEMENT OF POISONING WITH OP PESTICIDES... 

Although our military experience managing toxicity from nerve agent exposure is limited, exposures to related chemicals such as the OP class occur commonly each year in the USA. In 2006, there were a total of approximately 5,400 OP exposures across the USA (Bronstein et al, 2007). OPs, such as malathion, are commonly used as pesticides. OP toxicity manifests in a similar fashion as toxicity from nerve agents however, this chemical class is considerably less toxic. One case series of 16 children who experienced poisonings with OPs confirmed that pediatric patients present with toxicity differently than adults (Lifshitz et al, 1999). These children often did not manifest the classic muscarinic effects (such as salivary secretions and diarrhea) seen in adults. 

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