Your Health ;
It began as a routine checkup. A year after undergoing a kidney transplant, the 74-year-old patient was doing remarkably well. But when doctors reviewed his blood
tests, they discovered an alarming mystery. Levels of the
drug that was preventing the patient’s body from rejecting
the transplanted kidney had dropped significantly. “We had
no idea why at first,” says Joseph Boullata, associate professor of pharmacology and therapeutics at the University of
Pennsylvania School of Nursing.
It wasn’t until the hospital pharmacist
talked to the man’s daughter that they found
the explanation. The patient had begun taking a dietary supplement that included Saint
John’s wort, which is marketed to improve
mood. “No one had mentioned it because no
one really thought of it as a medicine,” says
Boullata. But Saint John’s wort can speed
the breakdown of some prescription medicines—including some of the drugs that prevent rejection—by eliminating them from
the body before they can take full effect.
If the blood test hadn’t alerted doctors, the
supplement might have triggered rejection
of the kidney—or even death.
Today, half of all Americans take dietary
supplements, according to the National Institutes of Health’s Office of Dietary Supplements. We spend more than $28 billion a
year on vitamins, minerals and herbal remedies such as echinacea, ginkgo and ginseng,
in hopes that they’ll cure everything from
insomnia to depression. And substances in
plants have been the basis for potent drugs
such as taxol to treat breast cancer and digitalis for heart disease. But because many dietary supplements are touted as “natural”
and are often sold in health food stores, it’s
easy to assume they’re harmless.
Sometimes they’re not.
While supplements can be
harmful at any age, men and
women age 50 and older are
more likely to encounter
problems. First, more older
people tend to have chronic
conditions like kidney or
liver disease, which make
it harder for the body to
process compounds found
in supplements. Then, too,
they usually take more pre-
scription drugs than younger people—and
the more medications you take, the greater
the risk of hazardous interactions with
supplements.
The Food and Drug Administration regulates dietary supplements but does not apply
the same rules it uses for medications. Manufacturers are not required to obtain approval
from the FDA before marketing supplements.
Under federal law, manufacturers are responsible for making sure their supplements are
safe, and the FDA steps in only when troubles
arise. Unfortunately, adverse interactions
with prescription drugs may go undetected
for a long time, even by physicians.
he manages a database of supplement information available to physicians and patients.
According to Yeung, about 50 percent of
cancer patients use some kind of dietary
supplement to ease symptoms or side effects—or, out of desperation, in search of a
cure. Yeung is convinced some herbs help
alleviate their symptoms. Unfortunately,
several popular supplements pose risks for
people with cancer. Saint John’s wort, the
same herb that washes antirejection drugs
out of the body, can also speed the breakdown of certain cancer chemotherapies,
robbing them of cancer-killing potency. And
vitamin C, in megadoses, can interfere with
the effectiveness of cancer drugs.
Even garlic can be risky
People taking anticoagulant medications to
prevent blood clots are vulnerable to dangerous interactions with supplements. Garlic may seem harmless, for example, but at
the high doses found in supplements, garlic
acts as a blood thinner. If you’re on a prescription drug to prevent blood clots, garlic
supplements may make your blood too thin,
increasing the risk of excessive bleeding.
Ginseng, green tea supplements and vitamin
K supplements can reduce the effectiveness
of certain blood-thinning drugs as well.
Also at risk are patients taking drugs for
depression or other psychiatric problems.
Ginkgo and ginseng have both been linked to
adverse interactions with psychiatric medications. Dietary supplements with psyllium,
which is used as a laxative, can cause problems by reducing absorption of prescription
medications, including carbamazepine and
lithium, which are widely used to treat psychiatric symptoms.
The extent of the danger isn’t clear because so little is known about many of the
GINSENG This popular herb can
reduce concentrations of the
anticoagulant drug warfarin and
can interact with some antidepressant medications.
Disturbing trend
It is troubling, then, that a recent AARP Public Policy Institute survey of people age 50
and older found that 59 percent had used
supplements in the previous month, and 52
percent took them daily. Fewer than half
said they talked to their doctors about the
pills they took.
“It’s a serious problem, and getting more
serious as the number of medications and
herbal products increases,” says K. Simon
Yeung, a pharmacist and herbalist at Memorial Sloan-Kettering Cancer Center, where
KAVA Promoted as a treatment
for insomnia and anxiety, kava has
been reported to cause liver damage,
including hepatitis and liver failure. It
may also impair driving ability.
LICORICE ROOT Taken for ulcers,
bronchitis and sore throat, licorice
root can cause high blood pressure
and salt and water retention, raising
the risk of heart problems.
MELATONIN Used for insomnia, it
can reduce the effectiveness of antidepressant, antianxiety and blood
pressure meds. It can increase bleeding risk if you’re on a blood-thinner.
