Q: 52 year old male is admitted to ICU after severe Organophosphate poisoning, requiring frequent Atropine IV pushes, followed by IV infusion. What is the best parameter to determine the titration of Atropine?

Answer: Secretions

Organophosphate poisoning results from exposure to insecticides/pesticides or nerve agents. Also, it is frequently used in suicides. The effects of organophosphate poisoning on muscarinic receptors are Salivation, Lacrimation, Urination, Defecation, increase Gastrointestinal motility, Emesis, Miosis(mnemonics are SLUDGEM or MUDDLES).

Established antidote is Atropine with dose around 3-5 milligrams every ten minutes. If symptoms continue, Atropine infusion can be started with 0.5-2.4 mg/kg/hr - till symptoms subsides. Longest reported infusion in literature is 5 weeks !!!Control of hyper-secretions served as the best monitoring parameter for titration of the drip rate.