A Study on Two Dose Regimens of Pralidoxime in the Management of Organophosphate Poisoning

The role and proper dose of pralidoxime in the treatment of Organophosphorus (OP) compounds poisoning is an unresolved issue. This study was designed to compare the regimen recommended by the World Health Organization (WHO) with the commonly used standard regimen of pralidoxime. This was a randomized open labeled prospective study on OP poisoned patients admitted to JSS Hospital, Mysore, India during November 2009 to January 2012. WHO regimen of 2 g pralidoxime bolus followed by 8mg/kg/h infusion (study group) compared with standard regimen of 2 g pralidoxime bolus followed by 1g 6 hourly (control group). In total, 82 patients were studied. Thirty-seven patients were randomized into the study group and 45 patients to the control group. All patients had moderate clinical severity. Although fewer patients in the study group required mechanical ventilation in comparison to the controls (12 vs. 22), the difference was not significant (P = 0.13). The death rate was lower in the study group though the difference was not also significant (P = 0.17). Mean (SD) duration of mechanical ventilation in the study group was significantly lower than controls (4.1 (1.6) vs. 6.6 (1.7) days; P = 0.01). Mean dosage of atropine administered was significantly lower in the study group compared to controls (345.0 (90.6) vs. 933.1 (162.3) mg; P = 0.001). Furthermore, 15 controls (33.3%) developed intermediate syndrome whereas no patient (0%) in the study group had such complication, which showed a significant difference (P < 0.001). A dose regimen of pralidoxime consisting of 2 g pralidoxime bolus followed by 8mg/kg/h infusion reduces morbidity and mortality in moderate cases of OP poisoning. The WHO dose regimen had significantly better outcomes compared to the standard dose regimen.