Organophosphorus (OP) compounds are chemical substances that come up with a significant toxicological threat. Several pesticides, fungicides, rodenticides were made of OPs, such as parathion, malathion, dimethoate, trichlorfon, dichlorvos, that were commonly used in Asia. In acute and chronic forms, OPs poisoning prevail in industry and agriculture. Due to the availability and toxicity, OPs poisoning happen regularly in accidental intoxication and suicides. Actually acute self-poisoning with organophosphate (OP) pesticides is common in rural Asia, and causes hundreds of thousands of deaths each year.
OP penetrates via the respiratory tract, alimentary tract and dermal integuments. OPs inhibit cholinesterase, and lead to the increase and accumulation of endogenous acetylcholine concentration, which then affect muscarinic ACh receptors functions mostly in central nervous system, heart muscle, bronchi, alimentary tract and nicotinic ACh receptors in muscular lamina.