Metrifonate or trichlorfon (USAN

United States Adopted Name

United States Adopted Names are unique nonproprietary names assigned to pharmaceuticals marketed in the United States. Each name is assigned by the USAN Council, which is co-sponsored by the American Medical Association , the United States Pharmacopeial Convention , and the American Pharmacists...

) is an irreversible 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...

 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 a prodrug which is activated non-enzymatically into 2,2-dichlorovinyl dimethyl phosphate (DDVP).

It can be used to treat schistosomiasis

Schistosomiasis

Schistosomiasis is a parasitic disease caused by several species of trematodes , a parasitic worm of the genus Schistosoma. Snails often act as an intermediary agent for the infectious diseases until a new human host is found...

 caused by Schistoma haematobium but is no longer commercially available.

It has been proposed for use in treatment of Alzheimer's disease

Alzheimer's disease

Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

, but use for that purpose is not currently recommended.