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Tuesday, February 4, 2003
Virulent poisons from the animal
kingdom are being used by researchers in their bid to find new
medicines to help prevent people from suffering from pain, according
to a report published by the Association of the British Pharmaceutical
Industry (ABPI) today.
Among the animals whose venoms are being studied
by pharmaceutical industry researchers are tarantula spiders, poison-dart
frogs and predatory marine snails.
Details of the research are published in Target
Pain, a new publication that looks at the different types of pain,
what causes them, how they are being tackled today, and various
new medicines that are under development in British laboratories.
"The UK-based pharmaceutical industry is
investing more than £8 million a day in the search for new
medicines, and the quest for better and more effective agents to
reduce pain is high on the list of priorities," said Dr Trevor
Jones, Director General of the ABPI.
"Our understanding of how pain is caused
has increased enormously over the past few years, and the next decade
will be critical in pain research. If we are successful, the lives
of countless thousands of people will be improved beyond measure."
The importance of controlling pain is demonstrated
by the fact that careful studies have shown that only about one-third
of people say they have been pain-free for the past six months,
and as many as one in 12 have experienced severe pain that is often
partially or fully disabling.
In 1995, the healthcare cost of chronic pain
exceeded that of coronary heart disease, AIDS and cancer put together.
As a result, the report calls pain "the silent epidemic".
Three types of pain are considered in the report:
- Acute pain -usually associated with injury
or trauma, and which resolves within hours or a few days.
- Chronic pain - pain which persists or recurs
over many months or even years.
- Neuropathic pain - which arises from within
the nervous system itself, often without any obvious cause.
Predatory conus snails have proved particularly
interesting to researchers. Up to four inches long, they feed on
a variety of molluscs, worms and small fish. They immobilise their
prey with venom that passes through a dart fired from a tentacle,
and the venom can prove fatal to humans.
A derivative of a compound from a conus venom
is in a late stage of development as a medicine, and could represent
the first of an entirely new class of medicines for the management
of neuropathic pain, currently the most difficult to treat.
Spiders have also provided leads, and the venom
from the Chilean pink tarantula is being used as a research tool,
providing a useful model for the synthesis of more stable derivatives.
Yet another lead from natural sources has come
from studies on dart-frogs - a colourful group of amphibians with
toxins on their skin that have been used by South American tribes
to poison the tips of their blow-darts.
While this is too poisonous for use in itself,
a derivative has been prepared that is as effective as morphine
but lacks the side-effects. This is currently in the first phase
of trials in patients.
The reason that animal venoms - an apparently unlikely source for
controlling pain in humans - are being studied is because of
their actions on nerves. By studying these effects, it has been
possible to gain further insight into pain mechanisms - and
even to develop potential medicines based on the structure of
the venoms themselves.
Written by a well-respected medical writer,
Dr Mike Hall, Target Pain is the latest in the ABPI's series of
reports studying individual disease areas. It is available free
from the Publications Department, ABPI, 12 Whitehall, London, SW1A
2DY; phone 020 7930 3477 extn. 1446; or email mfleming@abpi.org.uk.
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