Effectiveness of High Dose Pralidoxime for Treatment of Organophosphate Poisoning

Background: For effective treatment of organophosphate (OP) poisoning, development of a standardized protocol with flexible dose regimen for atropine and pralidoxime is an essential step. In this study, we aimed to assess the protocol devised in our setting; Bach Mai Hospital Poison Treatment Center, for treatment of OP poisoning that included a higher dose regimen of pralidoxime (2PAM). Methods: A protocol for treatment of OP poisoning was developed during 1995 to 1996, which included an atropinization scoring scale and a modification of 2PAM dose regimen. In this study, OP poisoned patients who were treated during 1997 to 2002 with the new protocol (study group or cases) were compared with historical control group which included OP poisoned patients treated between 1993 and 1994 prior to establishment of the new protocol. Results: One-hundred and eight cases and 54 controls were included. The cases and controls were not significantly different according to age, gender and plasma cholinesterase activity on admission from each other. There was no significant difference of mean duration of 2PAM therapy between the two groups. The controls received mean total 2PAM dose of 7.2±4.1 g, while the patients in the study group received 20.0±12.7 g which was 2.77 times higher than the dose for control group (P<0.001). Patients in the study group received significantly lower doses of atropine (100.2±119.1 vs. 231.8±225.5, P<0.001). Patients in the study group required a shorter duration of hospital stay compared to controls (6.2±4.8 vs. 8.2±5.8, P=0.035). In addition, morality rate decreased significantly (P=0.004) from 13% to 1.9% by application of the new protocol. Conclusion: The new protocol was more effective for patients with OP toxicity as it reduced the morbidities and mortality. A flexible regimen of 2PAM therapy for OP poisoning is recommended to be implemented.