Anti cholinergic drug.
Objective : To block the muscarinic receptors until the
organophosphate is metabolised away from the body.
Atropine : Adult dose : 2-5mg i.v. repeated every 5 min
doubling the initial dose.
Children : 0.05-0.1mg/kg
Given till signs of atropinization appear.
Continued treatment: maintenance dose (30% of
atropinization dose) for 1-2 weeks.
are used to restore neuromuscular
more reactive OH groups in the form of
oximes (Generic formula R-CH=N-OH) are
provided reactivation occurs more faster.
Pralidoxime ( 2-PAM)
Action of Pralidoxime (2-PAM)
Attaches to the anionic site of the enzyme.
Oxime end reacts with the phosphorus atom
attached to the esteratic site.
Oxime-phosphonate form and diffuse away.
Reactivated ChE remain.
Treatment should be started within 24 hours
before the phosphorylated enzyme undergoes
‘Aging’ and become resistant to hydrolysis.
is ineffective to carbamate poisoning as in
that case the anionic site of the enzyme is not
It is rather contraindicated because it has
weak anti-ChE activity of its own.
i.v. slowly in a dose of 1-2g.
may be repeated according to need.
of oximes in OP poisoning is secondary
to that of Atropine.
more potent than pralidoxime
Lipophilic; so if the OP poisoning symptoms
are more central DAM is used as it can cross
the blood brain barrier.