(ORGANOPHOSPHOROUS COMPOUNDS) - Highly lipophilic

  • Nerve gases: Sarin, Soman.
  • Insect killers: Malathion, Parathion, TEPP (tetraethylpyrophosphate)
  • Drugs used clinically: DFP (Diisopropyl flurophosphate)

MOA

Pharmacological Effects (All are toxic effects)

►Toxicity

 The signs and symptoms of over dosage are readily predicted from the general pharmacology of acetylcholine.   Muscarinic Toxicity These include CNS stimulation , meiosis, spasm of accommodation, bronchoconstriction, increased gastrointestinal and genitourinary smooth muscle activity, increased secretory activity (sweat glands, airway, gastrointestinal tract), vasodilatation, and bradycardia.

Nicotinic Toxicity These include CNS stimulation, ganglionic stimulation, and neuromuscular endplate depolarization leading to fasciculation and paralysis.

  • Muscarinic effects. (See above)
  • Nicotinic effects. (See above)
  • CNS effects. (See above)

►Treatment of the Untoward Effects

 Protection

  • Farmers who spray the insecticides should wear gloves and masks.
  • Thorough washing of vegetables.
  • Glasses containing domestic insecticides should be kept away from children.

Treatment

  • Stomach wash.
  • Wash the skin, if contaminated by sodium bicarbonate or ethyl alcohol.
  • Maintain the air passage open by sucking secretion and start artificial respiration if needed.
  • Atropine in high doses: 2 mg I.V. or I.M. every 5 -10 minutes until the patient is put on the merge of atropine toxicity (dilated pupil, dry mouth, and tachycardia). - The patient should be kept atropinized for 24 hours. The intoxicated patient may need up to 100 mg for full atropinization. Atropine eye drops may relieve the headache caused by miosis. The patient should be maintained on atropine until the enzymes are recovered. *Convulsions may be controlled by anticonvulsants (diazepam).