01/02/98- Updated 01:30 AM ET
Drug may be stronger than morphine
A deadly poison from the skin of a South American
frog provided the decisive clue for the discovery of
a powerful new painkiller that researchers say may
have all of the benefits of morphine but none of the
damaging side effects.
Researchers at Abbott Laboratories in North Chicago,
Ill., developed the painkiller, called ABT-594, after
National Institutes of Health (NIH) scientists
isolated a poison from the skin of an Ecuadorian frog
called Epibpedobates tricolor.
John Daly of the National Institute of Diabetes and
Digestive and Kidney Diseases found in 1976 that an
extract from the frog's skin could block pain 200
times more effectively than morphine. He called the
compound epibatidine. Although it appeared to be a
painkiller in rats, it was too toxic to use in
humans.
Ten years later, NIH researchers used new analytic
tools to determine the chemical structure of
epibatidine. A brief report on the compound, along
with a diagram of its chemical structure, was
published in the journal Science. Researchers at
Abbott realized that the chemical structure was close
to a group of experimental drugs that the company was
testing for treatment of Alzheimer's disease. They
screened some 500 compounds and selected the drug
ABT-594 for further testing. Its chemical structure
closely resembles epibatidine, but it doesn't have
the elements that made the frog compound toxic.
In Friday's Science, Abbott scientist Michael
Williams and his colleagues report that in animal
studies, ABT-594 appears to be many times more
powerful than morphine, but it lacks the serious side
effects.
According to Science, there are 30 million to 40
million Americans with moderate to severe pain that
is not affected by common analgesics. And there are
thousands with chronic pain who depend on morphine,
despite its side effects - respiratory problems,
constipation, addiction - just to get through the
day.
Many experts say there is an urgent need for new
painkillers. "If it works in people, it's going to be
a completely new kind of pain reliever," Howard
Fields, professor of neurology at the University of
California, San Francisco, said in Science.
ABT-594 is now in human safety testing, and the
results should be known by the summer, Williams says.
                By The Associated Press
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