Some Foods
and Medications Don't Mix
When Brian Foster gulped down an
eight-ounce glass of cranberry juice
one morning, he had no idea what was
in store. A few hours later, as he walked
down the halls of the University of
Ottawa’s Faculty of Medicine where he
teaches, his blood pressure dropped
suddenly and he began to stumble.
The episode soon passed, but Foster
realized his “overdose” of cranberry
juice had interfered with his medication,
metoprolol, a beta-blocker used to treat
high blood pressure.
“The reaction
was my own fault,” says Foster, who
studies common foods such as cranberry
juice and other natural health products
from Canadian sources.
Foster’s
a senior science advisor and a member
of the digestive diseases research group
in Health Canada’s science laboratory.
For nearly a decade, he’s been examining
the effects some natural and herbal
products may have on the way patients
metabolize prescription drugs.
About nine years ago, he learned
garlic could interfere with the AIDS
drug Ritonavir. A doctor in Manitoba
had discovered a link between garlic
and two of his AIDS patients when they
developed severe reactions. One had
eaten a whole garlic bulb a day. The
other was taking three times the recommended
dose of garlic tablets.
Foster
began to look at other alternative medicines
and natural health products such as
evening primrose oil, Earl Grey tea,
Echinacea, St. John’s wort, and even
red wine.
Although red wine is often
promoted as “heart smart,” in fact,
Foster and his team have found that
eight red wines have a very high potential
to interfere with drug metabolism.
“I’ve been keeping away from red
wine,” says Foster, who has a heart
condition. “There are many heart patients
out there who could suffer a negative
effect from red wine.”
Add a
plate of exotically spiced curry – perhaps
with ginger, cumin, turmeric or even
cinnamon – and the combination could
be even more threatening.
“All
chemicals carry a risk for most people,”
warns Foster. “The risk is very low,
but there are some people who are at
higher risk. And those who are on drugs
for AIDS or cancer, immuno-suppressives
for transplants, or some antibiotics
for cystic fibrosis face the risk of
something happening.”
Health
Canada, says Foster, is trying to get
this message out in a “user-friendly
way,” and making sure drugs carry the
appropriate warnings.
“Don’t
stay away from foods you like,” Foster
advises, “but be cautious. We suggest
people follow a balanced diet in moderation.
We find that when people have eaten
large amounts of one thing, together
with their drugs, that’s when these
things seem to happen.” |
