Drastic solutions

Suicide has become a national public health priority in Sri Lanka, as self-poisoning with highly toxic pesticides reaches alarming levels.

Suicide tends to be seen as a Western problem, but in fact suicide rates in the developing world are higher because people are more likely to die.

In Asia, the sparseness of medical facilities, access to highly toxic poisons – particularly the pesticides widely used in rural areas – and the lack of cheap antidotes means that self-poisoning is frequently fatal. The World Health Organization estimates that pesticides cause more than 220 000 deaths worldwide, and in Sri Lanka preventing suicide has become a national public health priority.

"In a moment of extreme stress – when the crops fail, when constraints and losses imposed by the war seem insurmountable, there are enough reasons at times – people just grab the nearest thing and drink it," explains Dr Michael Eddleston. In a poor rural area, where there are no medicines in the house, pesticides are often that nearest thing.

Dr Eddleston was first exposed to self-poisoning in Sri Lanka six years ago on a visit to study snakebite. He was struck by the number of patients in hospital who had poisoned themselves with yellow oleander seeds. "Oleander seeds look like conkers growing from trees, but they contain poisonous cardiac glycosides similar to the drug digoxin. People just peel off the skin and chew them. One of the junior doctors said to me, ‘snakebite that’s great, but if you really want to make our lives easier, solve the oleander problem’," he recalls. "So I went back there and studied it further, before carrying out a randomised controlled trial of antidigoxin antibodies as a treatment for oleander poisoning. We showed it worked very well, and the Sri Lankan Government is implementing the treatment. At the moment cost is a major problem because the drug is very expensive, but we are looking at cheaper means of making the antibodies using Indian manufacturers."

With an antidote now available for oleander poisoning, Dr Eddleston is turning his attention to the even bigger problem of pesticide poisoning. "Organophosphate pesticides, the commonest type of pesticide used in self-poisoning worldwide, are more toxic than oleander seeds and because they are drunk in liquid form they are absorbed faster into the body. A much larger proportion of patients die."

Organophosphate pesticides cause paralysis of the muscles used to breathe by inhibiting an enzyme, called acetylcholinesterase, which regulates nerve activation of muscles. "If that happens, you suffer a respiratory arrest. If you’re in hospital, you’re put on a ventilator, but if it happens out in the community you’d be very lucky to survive. Even in hospital, 20 per cent of patients die."

Large doses of atropine are normally given in these circumstances, but studies have suggested that another drug, pralidoxime, may reactivate the inhibited acetylcholinesterase, enabling nerve activations to start working again much faster. However, a large-scale randomised controlled trial has never been carried out.

Dr Eddleston recently received a Wellcome Trust grant to do just that. The study will be carried out in Kurunegala and Anuradhapura General Hospitals, secondary referral hospitals lying within an hour of each other in central Sri Lanka. In 1998, both had more than 1800 cases of poisoning, and 10–12 per cent of patients died. "We’re going to do a randomised controlled trial of 2000 patients with organophosphate poisoning, giving half of them atropine, the normal treatment, and the other half atropine plus pralidoxime," explains Dr Eddleston. "Then we’ll compare both populations to see whether there is an improvement in the number of patients who die or who have a respiratory arrest."

Activated charcoal

Whatever poison patients have taken, when they first arrive in hospital they are usually given activated charcoal as first-line treatment. Activated charcoal has been treated to increase its surface area to 2000 square metres per gram. "That’s the size of several tennis courts, packed into one gram," says Dr Eddleston. "That makes it incredibly absorptive. If you put that in a patient’s stomach immediately it will absorb a lot of the poison. Or, if the patient arrives too late to prevent absorption, activated charcoal in the bowel can increase elimination of the poison from the body by preventing it from being reabsorbed into the body if it passes out into the bowel again."

Dr Eddleston is therefore using the other half of his Wellcome Trust grant to conduct clinical trials to investigate the efficacy of activated charcoal. "Activated charcoal may reduce the poison level, but if it doesn’t actually give you a clinical benefit – if patients aren’t dying or going into intensive care at a lesser rate – then there’s little point using it. But if we can get evidence that it does work, then great. It’s cheap, safe and available, and it can be found throughout the developing world. It would be a very effective treatment for many poisons."

However, even if activated charcoal and pralidoxime are proven to be clinically effective, and antidigoxin antibodies for oleander-seed poisoning can be manufactured cheaply, there still remains the issue of getting these treatments to patients fast enough.

Dr Eddleston is working closely with the Sri Lankan Ministry of Health, the WHO, and local poison centres and medical communities, to try to arrange for the specific antidotes to oleander or pesticide poisoning to be available in peripheral hospitals. Patients could then be treated promptly, rather than having to endure a long drive to a secondary referral hospital first. "Because it’s so cheap and safe, activated charcoal should be available anywhere you can buy pesticides, in any little grocery shop in any village. So as soon as anyone finds out that one of their relatives has taken a poison, they can go there, grab the stuff, run back and give it to them. Then even if they don’t get to the hospital for four hours, they’ve still probably managed to absorb quite a lot of the poison."

Ultimately, of course, prevention is better than cure. "In the long run I’d like to develop ways of preventing suicide or self-harm in the first place," says Dr Eddleston. "The society in Sri Lanka is not one that’s terribly open about discussing feelings. You get the feeling the whole community, especially the young children, have learned that this is the way you deal with stressful situations. I’d like to do a trial of teaching coping skills in schools, explaining to children that there are other ways of responding to severe stresses than reaching for the bottle. But that’s a dream for the future."

External links

BMJ article ‘Deliberate self harm in Sri Lanka: an overlooked tragedy in the developing world’: Feature on Dr Michael Eddleston’s research (1998, 317:133-135)
Centre for Tropical Medicine at the University of Oxford : Includes brief details of Dr Michael Eddleston’s research in Sri Lanka
BBC News article ‘Third World faces self-harm epidemic ’ (10 July 1998): Features the research of Dr Michael Eddleston

Drastic solutions

Activated charcoal

See also

External links

Further reading