Nnews
Science | DOI: 10.1145/2347736.2347741
Neil Savage
Digging for Drug Facts
With the right approach, data mining can discover
unexpected side effects and drug interactions.
WHen peOple WitH high blood pressure start aking thiazide diuret- ics as treatment, they are warned about possible heart-related side effects, including palpitations, fainting, and even
sudden death. Patients taking a certain
class of antidepressants face similar
risks. But what if they are taking both
drugs together? Would the bad effects
be more likely? No one knew.
PhotograPh by erIn deMay
Not, that is, until researchers at
Stanford University used data-mining
techniques to pore through a database
of side effects. They discovered that
people taking both a thiazide diuretic
and a selective serotonin reuptake
inhibitor, such as Prozac, were about
one-and-a-half times as likely as people taking either drug separately to
show a prolonged QT interval, a measurement in cardiology that increases
the risk of those heart problems. In
mining the database, Russ Altman,
professor of medicine and biomedical informatics research, and Nicholas Tatonetti, who has since earned
his Ph.D. in biomedical informatics,
found an additional 46 drug pairs that
interacted to cause side effects that
had not been known before beyond
those of either drug alone.
Clinical trials do not test for drug
interaction; it would be costly and im-
practical to test every drug against every
other drug. And although the trials can
identify some side effects, other side
effects do not show up until a medication is given to a larger population of
patients over a longer period of time.
To keep tabs on unexpected compli-
cations from already approved drugs,
the U.S. Food and Drug Administra-
tion (FDA) created the Adverse Events
Reporting System (AERS), a database
of more than four million negative
events reported since 1969. Every three
months, the FDA releases a new batch
of event reports, which statisticians
can use to look for previously unrec-
ognized drug-related problems. Phar-
maceutical companies are required to
report bad effects associated with their
medications, and health professionals
and patients can also submit reports.
