Q: Atropine is considered as a mainstay antidote in organophosphate poisoning. The best marker of its effectiveness and titration is? (select one)
A) respiratory secretions
Atropine is considered as an antidote of organophosphate poisoning. There is no maximum dose, and should be used till the symptoms are resolved. It may require continuous intravenous (IV) infusion. Poison center/toxicologist should be called immediately for the guidance of doses at every step.
Atropine prevents cholinergic activation by competing for acetylcholine at muscarinic receptors. Resolution of respiratory secretions and bronchoconstriction are the best markers of resolving organophosphate poisoning and effectiveness of atropine. Heart rate and pupillary reactions can be very deceiving as they are subject to be highly influenced by hypoxemia, intravascular dehydration, and sympathetic stimulation.
Eddleston M, Roberts D, Buckley N. Management of severe organophosphorus pesticide poisoning. Crit Care 2002; 6:259.