PARAQUAT

Hoek & Konradsen 2005). Yet a study in
Korea in 2007, of 250 attempted suicides with
paraquat, revealed that only 38% of people had
intentionally selected paraquat as the agent,
indicating that if paraquat was not available
the survival rate from attempted suicide would
be significantly higher (Seok et al 2009). This
is very important, given that in countries such
as Sri Lanka intentional self-poisoning is “often
a result of impulsive behaviour rather than the
result of long-standing psychiatric problems”.
Sudden anger and grief are common triggers
(van der Hoek et al 1998). A Sri Lankan study
found that 85% of self-poisoning patients cited
easy availability as their basis for choice of
poison; more than 50% ingested the poison
less than 30 minutes after deciding to self-harm
(Eddleston et al 2006). Experience has shown
that restrictions on availability of paraquat (e.g.
in Samoa) and other highly toxic pesticides have
reduced deaths from poisoning (Roberts et al
2003; Gunnell et al 2007) – see also Figure 1.
Most intentional self-poisoning occurs
via ingestion, although injection with fatal
consequences has been reported in Korea (Kim
et al 2000; Choi et al 2008) and Taiwan (Hsu et
al 2003; Chen et al 2009).
Numerous cases of intentional paraquat selfpoisoning
have been reported in Malaysia,
South Korea, Taiwan, Thailand, and Sri Lanka.
It is reported to be less common in India – 6%
of 84 poisoning cases admitted to a Respiratory
Intensive Care Unit in North India between
1998 and 2006 involved paraquat (Agarwal et
al 2006). In 1993 Fiji and Japan were reported
to be countries with high rates of paraquat
poisoning, with the rate in Fiji being 47 deaths
per million people per year, and in Japan 11
deaths/million/year, compared with the USA rate
of 0.004/million/year (Tinoco et al 1993).
Sri Lanka
Thirty-two cases of paraquat poisoning,
including 10 deaths, were recorded in just 2
rural hospitals in Sri Lanka in a 1-year period
in 1998-99 (van der Hoek & Konradsen 2005).
Over a 2-year period, 2004-5, 774 paraquat
patients were registered with 9 rural hospitals.
Syngenta ran a study on these to compare
the outcome of the poisoning with their new
formulation Gramoxone INTEON, touted as a
partial solution to the suicide problem. Although
the rate of survival with the new formulation was
35.6% compared with 25.5% for the original
formulation, still 186 people died after ingesting
INTEON (Wilks et al 2008). Between 6 and 7
out of every ten people who ingested the new
formulation still died (Bateman 2008). A second
study of 533 paraquat poisonings in 10 hospitals
in Sri Lanka, from October 2006 to August
2008, failed to show any benefi cial effect of the
INTEON formulation (Wilks et al 2010).
South Korea
In South Korea, where paraquat has been
used for 3 decades, it is estimated to cause
2,000 poisonings annually, with a 40-50%
mortality rate. An investigation of 154 cases
with 34% fatality in 1999, found that 73.3% were
intentional ingestion (Hwang et al 2002). The
total number of pesticide poisoning deaths from
1996 through 2005 was 25,360. 84.8% of these
were from intentional self-poisoning. Paraquat
was the most frequent cause, accounting for
538 (35.5%) of all pesticide-related deaths (Lee
& Cha 2009). In 1999, the Korean Agricultural
Promotion Agency estimated that there were
800 deaths due to paraquat poisoning annually
in Korea. In 2005, that number had fallen to 256
cases in 9 months (Yoon 2009).
Thailand
Paraquat was responsible for 23.7% (376 cases
including 150 deaths) of all poisoning cases in
Thailand between the years 2001 and 2004. This
includes intentional and unintentional, adult and
child fi gures for pesticide poisoning in Thailand,
although the majority of all poisoning cases
were adult intentional (89.9%) (Wananukul et al
2007).
Japan
From 1998 to 2002, paraquat was responsible
for 20% of the 345 cases of pesticide poisoning
seen at hospitals affi liated with the Japanese
Association of Rural Medicine, with a mortality
rate of 70%. Suicide accounted for 70% of all
pesticide poisoning cases (Nagami et al 2005).
In 1990 Eisler reported that, in Japan, more than
1,000 persons each year are reportedly poisoned
by paraquat, but didn’t identify what proportion
of these were occupational poisonings.
Malaysia
During the period 1986-96, paraquat was
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