In OPC poisoning, OPC actions are:
a. Phosphorylated enzymeb. Irreversibly inhibit cholinesterase
c. Oximes effective when given beyond 24
d. Atropine can’t reverse in early stage
e. Dimercaprol is an antidote for OPC
Ans: (A) Phosphorylated enzyme; (B) Irreversibly inhibit
cholinesterase;
- Organophosphorus compounds are powerful inhibitors of
carboxylic esterase enzymes, including true acetylcholinesterase and
pseudoacetyl cholinesterase.
- It inactivates the esterase enzymes irreversibly by
phosphorylation
- Oximes reactivates the inhibited cholinecterase. They
should be started as early as possible in organophosphorus poisoning and may be
benificial when given even after 24 to 36 hrs of exposure.
- Oximes should be
started within 24 hours, before the phosphorylated enzyme has undergone ‘aging’
and become resistant to hydrolysis.
- Atropine is
highly effective in counteracting the ,nuscarinic effects, higher dose is
required to antagonize central effects. It is not effective against nicotinic
actions.
