- WASHINGTON (Reuters) - St.
John's wort, an herb commonly used by people to treat themselves for depression
and anxiety, can interfere with a key drug used in AIDS cocktails, as well
as a drug used for transplant patients, researchers said on Thursday.
- They said patients taking the drug indinavir, sold by
Merck under the name Crixivan, should be careful about taking St. John's
- ``When St. John's wort and the protease inhibitor indinavir
are taken together, the levels of indinavir in the blood drop dramatically,''
Dr. Stephen Piscitelli of the National Institutes of Health, who led the
study, said in a statement.
- This could allow the virus to come back and, worse, start
- ``Patients and health-care professionals need to be aware
of this interaction,'' added Dr. Judith Falloon of the National Institute
of Allergy and Infectious Diseases (NIAID), one of the institutes at the
NIH. ``Most people taking medications to treat HIV infection should avoid
using St. John's wort.''
- It is well known that what patients eat and drink can
affect the way drugs are absorbed and used by the body. For example, grapefruit
juice is known to increase the effectiveness of some HIV drugs, and some
of the drugs must be taken with food while others must be taken on an empty
- Other research has also shown that patients who take
alternative or herbal medicine often do not tell their doctors about it,
in part for fear the doctors will disapprove.
- ``There is a misconception that herbal products like
St. John's wort are safe, but this study demonstrates that there can be
dangerous interactions when taken with other drugs prescribed to treat
medical conditions. It is important for patients to tell their health-care
providers about their use of herbal products and complementary medicines,''
Piscitelli told the Lancet medical journal, which published the study.
- The NIH researchers saw reports on how St. John's wort
affects the body and feared it might affect the protease inhibitor class
of drugs used in treating HIV infection.
- They tested eight healthy volunteers, first giving them
three daily doses of Crixivan alone on an empty stomach, testing their
blood levels of the drug, and then adding St. John's wort capsules.
- ``The results were dramatically conclusive,'' Piscitelli
said. ``All the participants showed a marked drop in blood levels of indinavir
after taking St. John's wort. The drop ranged from 49 percent to 99 percent.''
- Protease inhibitors are often key to making HIV drug
cocktails work. They can keep the virus suppressed and keep patients healthy,
although they are not cured, but only if all the drugs are taken correctly.
- If drug levels fall -- for instance if something like
St. John's wort interferes or if the patient misses a few doses -- the
virus not only comes back with a vengeance but can mutate into forms that
resist the drugs.
- ``Resistance to indinavir can decrease the response to
other protease inhibitors,'' Piscitelli said.
- In a second study, Frank Ruschitzka and colleagues from
University Hospital, Zurich, in Switzerland said St. John's wort can also
interfere with cyclosporine, a drug used to keep patients from ``rejecting''
- Two patients who got heart transplants started suffering
acute rejection of their hearts and had to be hospitalized after taking
the herb. When they stopped taking St. John's wort, the cyclosporine levels
in their bodies returned to normal and their conditions improved, Ruschitzka
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