In which of the following poisoning, pralidoxime is ineffective?
Oximes are used to displace organophosphates from the active site of acetylcholinesterase, thus reactivating the enzyme. Pralidoxime is a specific antidote that restores acetylcholinesterase activity by regenerating phosphorylated acetylcholinesterase and appears to prevent toxicity by detoxifying the remaining organophosphate molecules. Clinically, pralidoxime ameliorates muscarinic, nicotinic, and central neurologic symptoms. Pralidoxime is not recommended for asymptomatic patients or for patients with known carbamate exposures presenting with minimal symptoms. There is increased toxicity of pralidoxime in carbaryl poisoning. Ref: Robey III W.C., Meggs W.J. (2011). Chapter 195. Pesticides. In J.E. Tintinalli, J.S. Stapczynski, D.M. Cline, O.J. Ma, R.K. Cydulka, G.D. Meckler (Eds), Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e.
Organophosphorus
Carbaryl
Both of the above
None of the above