Paraoxon is a parasympathomimetic which acts as an acetylcholinesterase inhibitor

Acetylcholinesterase inhibitor

An acetylcholinesterase inhibitor or anti-cholinesterase is a chemical that inhibits the cholinesterase enzyme from breaking down acetylcholine, increasing both the level and duration of action of the neurotransmitter acetylcholine.- Uses :Acetylcholinesterase inhibitors:* Occur naturally as...

. It is an organophosphate

Organophosphate

An organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...

 oxon, and the active metabolite

Metabolite

Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...

 of the insecticide parathion

Parathion

Parathion, also called parathion-ethyl or diethyl parathion, is an organophosphate compound. It is a potent insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, including humans. Its use is banned or restricted in many...

. It is also used as an ophthalmological drug against glaucoma

Glaucoma

Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...

. Paraoxon is one of the most potent acetylcholinesterase-inhibiting insecticides available, around 70% as potent as the nerve agent sarin

Sarin

Sarin, or GB, is an organophosphorus compound with the formula [2CHO]CH3PF. It is a colorless, odorless liquid, which is used as a chemical weapon. It has been classified as a weapon of mass destruction in UN Resolution 687...

, and so is now rarely used as an insecticide due to the risk of poisoning to humans and other animals. It is easily absorbed through skin, and was used as an assassination weapon by the apartheid-era South African chemical weapons program Project Coast

Project Coast

Project Coast was a top-secret chemical and biological weapons program instituted by the South African government during the apartheid era. Project Coast was the successor to a limited post-war CBW program which mainly produced the lethal agents CX powder and mustard gas; as well as non-lethal...

.