Introduction The benefits of
atropine in the treatment of acute
organophosphate (OP)
poisoning has been well established, while that of
oximes is still uncertain.
Pralidoxime is the most often used
oxime worldwide. In vitro experiments have consistently shown that
oximes are effective reactivators of human
acetylcholinesterase enzyme, inhibited by OP compounds. However, the clinical benefit of
pralidoxime is still unclear. A recent meta-analysis has found that
pralidoxime provides no significant improvement in outcome and rather may cause harm while increasing the economic burden in low-income communities where its use is the most prevalent. Objectives This study aimed to provide an updated evaluation of the efficacy of
pralidoxime in addition to
atropine alone in the treatment of patients with acute OP
poisoning in terms of mortality, need for
ventilator support, and the incidence of intermediate syndrome. The intermediate syndrome is a clinical syndrome that occurs 24 to 96 hours after the ingestion of an OP compound and is characterized by prominent weakness of neck flexors, muscles of respiration, and proximal limb muscles. Materials and methods We searched MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov databases until January 2019 for randomized controlled trials (RCTs) in the English language that evaluated the use of
pralidoxime in individuals of any age, gender or nationality presenting with an alleged history of OP intake. The primary outcome was mortality. Secondary outcomes were the need for ventilator support and the incidence of intermediate syndrome. The risk of bias in included studies was assessed using the tool recommended by the Cochrane Handbook of Systematic Review of Interventions. Treatment/control differences in these outcomes across included studies were combined using risk ratios (RR). Results Six randomized controlled trials (n = 646) fulfilled the inclusion criteria, including one further trial missed from the most recent systematic review. The risk of bias varied across studies, with Eddleston 2009 being of the lowest risk and Cherian 2005 being of high risk. The risk of mortality (RR = 1.53, 95% confidence interval (CI) 0.97 to 2.41, P = 0.07) and the need for
ventilator support (RR = 1.29, 95% CI 0.97 to 1.71, P = 0.08) were not significantly different between the
pralidoxime and the control group. There was a significant increase in the incidence of intermediate syndrome in the
pralidoxime group (RR = 1.63; 95% CI 1.01 to 2.62, P = 0.04). Conclusions Based on our meta-analysis of the available RCTs,
pralidoxime was not shown to be beneficial in patients with acute OP
poisoning. Our findings are consistent with the other literature.