Provided are N-alkyl imidazole 2-aldoximes, including cationic imidazolium and uncharged tertiary imidazole aldoximes, and compositions and methods for making and using them, including methods for reactivating human butyrylcholinesterase (hBChE) or acetylcholinesterase (hAChE ) inhibited by organophosphate (OP). By administration of a composition of the invention, the inactive or conjugated hBChE-OP or hAChE-OP is reactivated and the catalytic cycle of turnover and inactivation of the OP is completed and in alternative embodiments, secondary mechanisms of reversible protection of hBChE and hAChE from irreversible inactivation by OPs and reactivation of tissue AChE also contribute to overall efficacy.
