OPC Poisoning
Content
• Organophosphorous
poisoning and its treatment
Objectives
At the end of this
lecture, student will be able to
• Explain
organophophorous poisoning and its treatment
Choline esterase inhibitors (Anticholine esterases)
Irreversible choline esterase inhibitors
• OPC
• Useful:
Di isopropyl fluorophosphate, metrifonate, echothiophate
• Insecticides:
Fenthion, malathion, sumithion, monocrotophos, octamethyl pyrophosphotetramide
Irreversible Anti ChE
• Absorbed
by all the routes
• Cross
BBB
• Glaucoma:
echothiophate
• Toxicological
importance
OPC Poisoning
Muscarinic effects
• Eyes:
Miosis, spasm of accomodation, head ache, conjunctival hyperemia
• inhalation: bronchospasm, cough, increases
secretions, tightness in chest
• Ingestion:
anorexia, nausea, vomitting, abdominal cramps, tenesmus and diarrhoea
• Severe
bronchospasm, pulm. edema – fatal
Nicotinic effects
• Fasciculations,
twitching, generalised weakness, depolarisation type paralysis
Central effects
• Giddiness,
anxiety, confusion, ataxia, hypotension, respiratory depression, convulsion,
coma
• Death
– due to respiratory paralysis
Neurotoxic effects
• Demyelination
of nerve tracts in CNS & PNS
• Permanent
functional derrangements
• Not
related to ChE inhibition
• Weakness,
fatiguability, twitching, loss of tendon reflexes
Treatment of acute OPC Poisoning
• Remove
soiled clothes
• Wash
soiled skin/ eyes
• Nurse
in prone position
• Clear
mouth, throat
• Insert
airway/ intubate
• Gastric
lavage
• Atropine
in sufficient qty.
• ChE
activator: Pralidoxime (1-2 g)
• Supportive
measures: Oxygen, shock treatment
• Convulsion:
Diazepam
• Vigilance
for delayed toxicity
• Note:
Mouth to mouth respiration to be avoided
Summary
• Cholinergic
drugs stimulate effector cells innervated by cholinergic nerves
• Cholinergic
drugs: Ester of choline, Cholinomimetic alkaloids, Choline esterase inhibitors
(Anticholine esterase)
• Acetylcholine
actions – mostly inhibitory; stimulatory on digestion and exocrine glands
• Pralidoxime
is the antidote for OPC poisoning
