To expand further, atropine is used to reverse MUSCARINIC symptoms (i.e. "DUMBBELSS": Diarrhea, Urination, Miosis, Bradycardia, Bronchospasm, Emesis, Lacrimation, Salivation, Sweating) and it can also cross the BBB to relieve the CNS symptoms (i.e. respiratory depression, lethargy, seizures, coma). However, pralidoxime is used to reverse NICOTINIC symptoms (i.e. the neuromuscular blockade). Pralidoxime CANNOT cross the BBB and therefore cannot relieve CNS symptoms. And always give atropine before pralidoxime because pralidoxime can cause transient acetylcholinesterase inhibition, which will worsen the symptoms.
Organophosphate poisoning = Antidote = Atropine (Airway M receptor blocker) = dilation of bronchioles
submitted by โmcl(670)
To expand on this, organophosphates are commonly used as insecticides, and function by binding acetylcholinesterase and "deactivating" it, so to speak. This results in an excess of ACh within the synapse, which causes sludge syndrome (vomiting, sweating, diarrhea -- basically lots of fluids). The treatment for this is typically atropine (antimuscarininic), and pralidoxime (if given early enough, can "reactivate" the ACh-ases). The diagram given does not show ACh-ase, only the ACh-R, therefore D is the best answer.