Clinical Observation of Anticholinesterase-inhibitor Insecticides Poisoning

Hwang, Joo Ho; Yang, Dong Ho; Hong, Sae Yong

Abstract

BACKGROUND: Organophosphate and carbamate insecticides have been used extensively in agriculture resulting in serious increases in poisoning. Levels of poisoning by carbamates and organic phosphorus compounds and the severity of associated symptoms are dependent not only on the degree of reduction of acetylcholinesterase activity in the nervous system but also on the rate of inhibition and the type of inhibitive action. The most striking differences between the clinical effects of the two groups of compounds are the much more rapid and spontaneous recovery from poisoning by carbamates and the relatively large difference between the smallest dosage of any carbamate that will cause mild illness and the lethal dosage of the same compound. The purpose of this study is to compare the clinical characteristics of acute intoxication by organophosphate and carbamate insecticides. METHOD: We retrospectively analyzed the clinical characteristics of 41 patients poisoned with organophsphates and 12 patients poisoned with carbamates, who were admitted to the department of internal medicine, Soonchunhyang Chunan hospital from January 1995 to December 1996.
RESULTS
1) The most common organophosphate was EPN (9 cases) followed by Dichlorvos (7 cases). In the carbamates group, Carbofuran (5 cases) was the most common followed by Methomyl (3 cases).2) The main cause of poisoning was ingestion for the purpose of suicide in both groups.3) The severity of poisoning was more acute in the organophosphate group than in the carbamate group.4) Altered consciousness and respiratory depression occurred more frequently in the organophosphate group than in the carbamate group. Six cases out of the organophosphate group suffered from respiratory depression 24 hours to 96 hours after poisoning.5) The activity of serum cholinesterase showed no significant difference between poisoning with organophosphates and with carbamates.6) The mortality rate was 22% in organophosphate intoxication and 16.7% in carbamate intoxication. The most common complication of organophosphate and carbamate intoxication was aspiration pneumonia.
CONCLUSION
Carbamate insecticides exhibited less toxicity than organophosphates.