; Your Health
active ingredients in supplements.
The sheer number of possible combinations of prescription medications and supplements makes it
almost impossible to anticipate all
potential adverse reactions.
“There are 5,300 distinct dietary
supplements, and very few of them
have been studied systematically,”
says Vanessa Grubbs, M.D., an ex-
pert in kidney disease at San Fran-
cisco General Hospital. So few di-
etary supplements have been tested
to see how they interact with pre-
scription drugs that no one really
knows exactly which combinations
are likely to cause trouble. Antici-
pating problems is even harder
because the ingredients in herbal
combinations may vary from batch
to batch, experts say.
SAINT JOHN’S WORT
Marketed as an aid to
improve mood, Saint John’s
wort can reduce the ef-
fectiveness of a variety of
prescription medications,
including anticoagulants
and antidepressants. It also
can decrease the effective-
ness of cancer drugs by up
to 40 percent.
VITAMIN K Essential for
health, vitamin K helps in
blood coagulation. Taking
too much can block the
effect of the medication
warfarin, used to prevent
blood clots.
YOHIMBE Added to some
erectile dysfunction herbal
supplements, yohimbe can
cause seizures, severe low
blood pressure or heart
problems. Yohimbe may
interact with a variety of
medications.
ZINC Touted as a defense
against colds, excess zinc
can cause nausea, vomiting,
loss of appetite, stomach
cramps, diarrhea and headaches. It can interact with a
variety of prescription drugs,
including antibiotics and
hypertension meds.
