Office of Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/26
Title and Subtitle: Reactions of methamidophos with mammalian cholinesterases
Report Date: July 1978
Authors: Robinson CP,Beiergrohslein D, Smith PW, Crane CR
Abstract: The lethality of methamidophos, a phosphoramidothioate, to rats (i.p. LD50, 15 mg/kg), is similar to that of such potent organophosphate compounds as parathion and paraoxon. Certain distinctive features of its chemical structure, and reported failure of cholinesterase inhibited with methamiodophos to reactivate spontaneously in insects, prompted this study of its reactions with mammalian cholinesterase to determine if the treatment of poisoning requires modification.
Atropine (10 mg/kg) or pralidoxime (60 mg/kg) afforded significant protection against lethality from methamidophos (LD50's, 60 + or - 0.4 and 52 + or - 4.9 mg/kg, respectively). Partial spontaneous recovery of inhibited cholinesterase activity was observed. However, a single dose of pralidoxime, given essentially simultaneously with methamidophos, did not hasten the recovery of cholinesterase activity.
Key Words: Methamidophos, Organophosphates, Atropine, Pralidoxime
No. of Pages: 10
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/26
Title and Subtitle: Reactions of methamidophos with mammalian cholinesterases
Report Date: July 1978
Authors: Robinson CP,Beiergrohslein D, Smith PW, Crane CR
Abstract: The lethality of methamidophos, a phosphoramidothioate, to rats (i.p. LD50, 15 mg/kg), is similar to that of such potent organophosphate compounds as parathion and paraoxon. Certain distinctive features of its chemical structure, and reported failure of cholinesterase inhibited with methamiodophos to reactivate spontaneously in insects, prompted this study of its reactions with mammalian cholinesterase to determine if the treatment of poisoning requires modification.
Atropine (10 mg/kg) or pralidoxime (60 mg/kg) afforded significant protection against lethality from methamidophos (LD50's, 60 + or - 0.4 and 52 + or - 4.9 mg/kg, respectively). Partial spontaneous recovery of inhibited cholinesterase activity was observed. However, a single dose of pralidoxime, given essentially simultaneously with methamidophos, did not hasten the recovery of cholinesterase activity.
Key Words: Methamidophos, Organophosphates, Atropine, Pralidoxime
No. of Pages: 10
Last updated: Friday, June 1, 2012