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Intervention Review

Oximes for acute organophosphate pesticide poisoning

  1. Nick Buckley1,*,
  2. Michael Eddleston2,
  3. Ladislaus Szinicz3

Editorial Group: Cochrane Injuries Group

Published Online: 8 OCT 2008

Assessed as up-to-date: 11 NOV 2004

DOI: 10.1002/14651858.CD005085

Database Title

Additional Information

How to Cite

Buckley N, Eddleston M, Szinicz L. Oximes for acute organophosphate pesticide poisoning. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD005085. DOI: 10.1002/14651858.CD005085.

Author Information

  1. 1

    University of NSW, Professorial Medicine Unit, POWH Clinical School, Randwick, NSW, Australia

  2. 2

    University of Oxford, Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford, UK

  3. 3

    German Armed Forces Medical Academy, Institute of Pharmacology and Toxicology, Munich, Bavaria, Germany

*Nick Buckley, Professorial Medicine Unit, POWH Clinical School, University of NSW, South Wing, Edmund Blackett building, Prince of Wales Hospital, Randwick, NSW, 2031, Australia. n.buckley@unsw.edu.au.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 8 OCT 2008

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary

Background

Acute organophosphorus pesticide poisoning causes tens of thousands of deaths each year across the developing world. Standard treatment involves administration of intravenous atropine and oxime to counter acetylcholinesterase inhibition at the synapse. The usefulness of oximes, such as pralidoxime and obidoxime, has been challenged over the past 20 years by physicians in many parts of the world, who have failed to see benefit in their clinical practice.

Objectives

To find the clinical trial evidence for oximes producing clinical benefit in acute organophosphorus pesticide-poisoned patients.

Search strategy

We carried out a systematic search to find randomised clinical trials (RCTs) of oximes in acute organophosphorus pesticide poisoning, using MEDLINE, EMBASE and Cochrane databases. All articles with the text words 'organophosphate' or 'oxime' together with 'poisoning' or 'overdose' were examined. (Search last updated November 2003.)

Selection criteria

Articles that could possibly be randomised clinical trials were retrieved to determine if this was the case.

Data collection and analysis

The published methodology of the possible RCTs located is not clear. One was found in abstract form only and two other published trials also had many gaps in the published methodology. We have attempted to contact the principal authors of all three trials but have been unable to obtain further information.

Main results

Two RCTs have been published, involving 182 patients treated with pralidoxime. These trials did not find benefit. However, the studies did not take into account a number of issues important for outcome and the methodology is unclear. Therefore, a generalised statement on effectiveness cannot be supported by the published results. In particular, characteristics at baseline were not evenly balanced, the dose of oxime was much lower than recommended in guidelines, there were substantial delays to treatment, and the type of organophosphate was not taken into account. The abstract of the third trial, a small possible RCT, is uninterpretable without further data.

Authors' conclusions

Current evidence is insufficient to indicate whether oximes are harmful or beneficial in the management of acute organophosphorus pesticide poisoning. A much larger RCT is required to compare the World Health Organization recommended pralidoxime regimen (>30 mg/kg bolus followed by >8 mg/kg/hr infusion) with placebo. There are many theoretical and practical reasons why oximes may not be useful to patients with overwhelming self-poisoning. Such a study will need to be designed with pre-defined sub-group analysis to allow identification of patient sub-groups that may benefit from oximes.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary

No evidence that oximes are a useful treatment for organophosphate pesticide poisoning

Many thousands of people die every year because of poisoning by organophosphate pesticides. Most of the deaths are in developing countries. Drugs known as oximes are used as part of the standard recommended treatment, even though many doctors have said that they don't seem to have any benefit. The reviewers found that very little research has been done to see whether oximes are actually effective. This research produced no evidence in favour of using oximes. However, the studies that were found had many limitations and more research is needed before any firm conclusions can be drawn.

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