No evidence that WHO-recommended treatment for insecticide poisoning improves survival

Jun 30, 2009

A study published this week in the open access journal PLoS Medicine finds no evidence to suggest that a controversial antidote recommended by the World Health Organisation (WHO) to treat patients poisoned with highly toxic insecticides improves their chance of survival. The results may even add weight to existing concerns about pralidoxime, the treatment recommended by the WHO, by suggesting that it could be harmful in patients who have deliberately poisoned themselves with insecticides.

Poisoning with organophosphorous pesticides - toxic chemicals commonly used in agriculture in developing countries is a global problem causing an estimated 200,000 deaths a year. Deliberate self-poisoning with pesticides is a common method of suicide in some countries- in Sri Lanka, more than 50% of fatal suicide attempts are a result of pesticide poisoning.

Michael Eddleston, from the University of Edinburgh, and colleagues conducted a clinical trial to study the effects of WHO-recommended pralidoxime treatment in patients who had been admitted to two hospitals in Sri Lanka for insecticide self-poisoning. If ingested by humans the pesticides disrupt the communication between the brain and body, inhibiting the activity of a neurotransmitter called , which plays a crucial role in the and the control of breathing. To treat organophosphate poisoning, the WHO recommends that in addition to atropine, an that is known to reverse some but not all of the effects of the poisoning, a regimen of pralidoxime should be used to reactivate acetylcholine activity. As the authors of this study mention, few randomized clinical trials have been conducted into its use, meaning that there is a lack of evidence for its effectiveness, in particular relating to dosage.

The researchers enrolled 235 patients at two Sri Lankan hospitals who had self-poisoned with organophosphate insecticides, determining how much, and which, pesticide each patient had been exposed to, and randomly allocating them to receive either the WHO-recommended regimen of pralidoxime or a salt water placebo. However, the trial was stopped early and did not reach its intended study size owing to discussions surrounding the results of another trial of pralidoxime therapy, carried out in India at the same time which led to a fall-off in recruitment of patients. In the Sri Lankan trial, published in PLoS Medicine, more patients in the pralidoxime arm died than in the placebo arm, despite the fact that pralidoxime was shown to aid acetylcholine activity. Whilst the difference in mortality between arms was not statistically significant, it is suggestive of a higher mortality rate resulting from pralidoxime treatment.

Acknowledging the difficult situation that clinicians now face when deciding whether or not to administer pralidoxime to patients poisoned with organophosphorous pesticides, the authors conclude that there is no consistent clinical evidence for the use of pralidoxime in patients who have self-poisoned with organophosphorous pesticides. They argue that further trials are needed to explore the risks and benefits of oximes and dosing regimens.

More information: Eddleston M, Eyer P, Worek F, Juszczak E, Alder N, et al. (2009) Pralidoxime in Acute Organophosphorus Insecticide Poisoning—A Randomised Controlled Trial. PLoS Med 6(6): e1000104. doi:10.1371/journal.pmed.1000104, medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.1000104

Source: Public Library of Science (news : web)

Explore further: Experts call for higher exam pass marks to close performance gap between international and UK medical graduates

add to favorites email to friend print save as pdf

Related Stories

Who benefits from antidepressants?

Feb 26, 2008

A new study published today in PLoS Medicine suggests that antidepressants only benefit some, very severely depressed patients.

Half of trials supporting FDA applications go unpublished

Sep 23, 2008

Over half of all supporting trials for FDA-approved drugs remained unpublished 5 years after approval, says new research published in this week's PLoS Medicine. The most important trials determining efficacy, and those with s ...

Recommended for you

Obese British man in court fight for surgery

Jul 11, 2011

A British man weighing 22 stone (139 kilograms, 306 pounds) launched a court appeal Monday against a decision to refuse him state-funded obesity surgery because he is not fat enough.

2008 crisis spurred rise in suicides in Europe

Jul 08, 2011

The financial crisis that began to hit Europe in mid-2008 reversed a steady, years-long fall in suicides among people of working age, according to a letter published on Friday by The Lancet.

New food labels dished up to keep Europe healthy

Jul 06, 2011

A groundbreaking deal on compulsory new food labels Wednesday is set to give Europeans clear information on the nutritional and energy content of products, as well as country of origin.

Overweight men have poorer sperm count

Jul 04, 2011

Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting Monday.

User comments : 0

More news stories

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...