Management of acute organophosphorus pesticide poisoning

Abstract

Organophosphorus (OP) pesticide self-poisoning is a major clinical problem across the rural developing world, killing an estimated 200,000 people every year. Medical management is difficult, with case fatality often over 20%. In this review, we describe the limited evidence base that should guide therapy. Fifty years after first being used, we still do not know how the core treatment - atropine, oximes, and diazepam - should best be administered. Major constraints in collecting useful data have been the late recognition of great variety among OPs and the care that cholinesterase assays require for their results to be interpreted or compared between studies. However, consensus exists that early resuscitation with atropine, oxygen, respiratory support, and fluids is required to improve oxygenation of patients. The role of oximes is unclear - they may only benefit patients poisoned by some OPs or patients with moderate poisoning. Small studies have suggested possible benefit from new treatments, eg. magnesium sulphate, but much larger trials are needed. Gastric lavage may have a role but should only be considered once the patient is stable. RCTs are now underway in rural Asia to address particular aspects of therapy. However, some specific OP pesticides may ultimately prove very difficult to treat with current treatments such that focused bans may be the only method to substantially bring down the case fatality for OP poisoning. Improved medical management of OP poisoning will result in a marked reduction in the global number of deaths from suicide.