Irreversible Acetylcholinesterase Inhibitors

The only drug in the class used clinically is echothiophate.  Echothiophate is used in the treatment of open angle glaucoma; however, use is limited as the medication can cause cataracts.  Malathion and parathion are insecticides that result in cholinergic crisis upon exposure. Sarin is a chemical warfare agent that is used in terrorism and war and results in deadly cholinergic crisis.  

Reversal of malathion, parathion, and sarin exposures is accomplished using a combination of drugs. Pralidoxime (2-PAM) is a drug used to reactivate inhibited AChE. Pralidoxime does not cross the blood-brain barrier so only affects peripheral toxicity.  In addition to administration of pralidoxime, poisoned patients are also generally given atropine to counteract the effects of the agents. Additionally, benzodiazepines such as diazepam can be used to treat the convulsions caused by toxic exposure.   

Class Drugs

• Echothiophate

• Malathion 

• Parathion

• Sarin

Class Mechanism of Action

• Binds to active site of AChE (acetylcholinesterase)

Class Adverse Effects

• Diarrhea

• Urination

• Miosis

• Bradycardia

• Emesis

• Lacrimation

• Lethargy

• Salivation

Drug Table

Drug Name	Application	Comments	Image
Echothiophate	Chronic open angle glaucoma	Can cause glaucoma	"Radar" and "Theo"
Malathion		Insecticide	"Mallet" and "Ion"
Parathion		Insecticide	"Parrot" and "Ion"
Sarin		Chemical Nerve Agent	"Saran Wrap"