Comparative study between two obidoxime regimens in acute organophosphate toxicity among some Egyptian patients

ABSTRACT

Organophosphorus [OP] poisoning is commonly encountered in agricultural communities probably due to the easy accessibility to the insecticide. In vitro studies in animals and on human erythrocytes have suggested beneficial effects of oximes on reactivating acetylcholine esterase [AChE] enzyme. This study was a single blinded randomized clinical trial to investigate the comparative effectiveness of the World Health Organization [WHO] obidoxime regimen with recommended dose - 250 mg IV shot loading dose then infusion of 750 mg every 24 hours [high-continuous dose regimen] versus the regimen of National Egyptian Center of Toxicology and Research [NECTR], Faculty of Medicine, Cairo University with recommended dose 250 mg in 150 ml saline, IV infusion over one hour and repeated every 6 hours over a period of 24 hours from the time of admission [low-interrupted dose regimen]. Twenty normal individuals were recruited as control [group I], with their AChE enzyme level determined to assess the normal level in the population. Fourty patients exposed to OP and treated with the WHO obidoxime regimen were classified as group II. Fourty patients exposed to OP and treated with the NECTR obidoxime regimen were classified as group III. There were significantly higher percent of patients in group III with respiratory depression than in the patients of group II [p<0.05]. There were no statistically significant differences between the patients of group II and the patients of group III regarding all other signs and symptoms of OP poisoning as well as AChE enzyme levels in the first 12 hours [p>0.05]. After 12 hours from admission, the AChE levels were progressively and significantly higher in the patients of group II than the patients of group III until discharge [p<0.05]. The severity of respiratory failure, as measured by the need for ventilation and the number of ventilated patients were significantly. higher in the patients of group III than in the patients of group II [p<0.05]. The outcomes, such as the occurrence of respiratory depression and the number of deaths, were reduced in the patients of group II. There was statistically significant difference between the patients of group II and the patients of group III regarding the time of recovery [p<0.05]. There were no deaths between the patients of group II but one patient died from group III. This indicates that the WHO regimen [high-continuous dose regimen] is more effective than the NECTR regimen [low-interrupted dose regimen] in reactivating AChE enzyme, reducing the duration of hospital stay and the mortality rate and increasing the early recovery rate. Regarding the collected results of the present work, we recommend the use of the WHO obidoxime regimen