Pralidoxime is not effective in the treatment of poisoning due to phosphorus, inorganic phosphates, or organophosphates not having anticholinesterase activity.
Pralidoxime is not indicated as an antidote for intoxication by pesticides of the carbamate class since it may increase the toxicity of carbaryl. In therapy it has been difficult to differentiate side effects due to the drug from those due to the effects of the poison.