[Paleopsych] Quack Watch: St. John's Wort
checker at panix.com
Sun Apr 10 17:52:04 UTC 2005
St. John's Wort
[Following the Better Humans article, here's one from a professional
debunking group. I wonder who finances them.]
Stephen Barrett, M.D.
St. John's wort (Hypericum perforatum) has been widely claimed to be
effective as an antidepressant. The mechanism of action is unknown;
and the active ingredient, if any, has not been ascertained .
Studies of extracts standardized for hypericin (one of the herb's
constituents) have found it to be about twice as effective as a
placebo. A few studies have found it somewhat more effective than a
standard antidepressant. However, none of these studies lasted more
than six weeks, which is not long enough to determine how long the
herb would be effective or to detect any long-term adverse effects
. In addition, some of the studies were not well-designed [3,4]. In
most of these studies, the diagnosis was not well established, the
placebo response rate was lower than usually seen in such studies, the
dosage of standard antidepressants was low, and the dosage of
hypericin varied more than six-fold. . No serious side effects were
reported, but minor side effects include gastrointestinal discomfort,
fatigue, dry mouth, dizziness, skin rash, and hypersensitivity to
sunlight. However, in February 2000, British journal Lancet carried
reports that St. John's wort could interfere with the effectiveness of
an AIDS remedy (indinavir) ; an immunosuppressive drug
(cyclosporin) used to protect patients after heart transplantation
; and an anticoagulant (warfarin) . Based on this study and
other reports in the medical literature, the FDA issued a Public
Health Advisory stating:
St. John's wort appears to be an inducer of an important metabolic
pathway, cytochrome P450. As many prescription drugs used to treat
conditions such as heart disease, depression, seizures, certain
cancers or to prevent conditions such as transplant rejection or
pregnancy (oral contraceptives) are metabolized via this pathway,
health care providers should alert patients about these potential
drug interactions to prevent loss of therapeutic effect of any drug
metabolized via the cytochrome P450 pathway .
St. John's wort should not be used by women who are pregnant or are
breastfeeding. Nor should it be used together with standard
antidepressants. The potency and purity of the preparations sold in
the United States are unknown .
There is no published evidence that St. John's wort is effective
against severe depression, which, in any case, should receive
professional help. For mild depression, psychotherapy directed at
resolving the cause of the depression might be more prudent.
The NIH Office of Alternative Medicine has funded a 3-year,
$4.3-million clinical trial that will compare the effects of
hypericum, a placebo, and a standard antidepressive drug on patients
who are followed for up to six months . The results are expected in
the year 2002. Regardless of the outcome, however, another problem
must be overcome before consumers could use St. John's wort
effectively. A Good Housekeeping Institute analysis of six widely
available St. John's wort supplement capsules and four liquid extracts
revealed a lack of consistency of the suspected active ingredients,
hypericin and pseudohypericin. The study found:
* A 17-fold difference between the capsules containing the smallest
amount of hypericin and those containing the largest amount, based
on manufacturer's maximum recommended dosage.
* A 13-fold difference in pseudohypericin in the capsules.
* A 7-to-8-fold differential from the highest to the lowest levels
of liquid extracts .
A sinilar investigation by the Los Angeles Times found that 7 of10
products contained between 75% and 135% of the labeled hypericin
level, and three contained no more than about half the labeled potency
1. St. John's Wort. The Medical Letter 39:107-108, 1997.
2. Linde K and others. St. John's wort for depression -- an
overview and meta-analysis of randomised clinical trials. British
Medical Journal 313:253-258, 1996.
3. De Smet PAGM, Nolen WA. St. John's wort as an antidepressant:
Longer term studies are needed before it can be recommended in
major depression. British Medical Journal 313:241-242, 1996.
4. Gaster B, Holroyd J. St. John's wort in depression. Archives of
Internal Medicine 160:152-156, 2000.
5. Piscitelli SC and others. Indinavir concentrations and St
John's wort. Lancet 355:547, 2000.
6. Ruschitzka F and others. Acute heart transplant rejection due
to Saint John's wort. Lancet 355:548, 2000.
7. Jobst KA and others. Safety of St John's wort. Lancet 355:576,
8. Lumpkin MM, Alpert S. Risk of drug interactions with St. John's
wort and indinavir and other drugs. FDA Health Advisory, Feb 10,
9. St. John's wort study launched. Complementary and Alternative
Medicine at the NIH 4(4):5, October 1997.
10. Good Housekeeping Institute. New Good Housekeeping Institute study
finds drastic discrepancy in potencies of popular herbal
supplement. News release, Consumer Safety Symposium on Dietary
Supplements and Herbs, New York City, March 3, 1998.
11. Monmaney T. Labels' potency claims often inaccurate, analysis
finds. Spot check of products finds widely varying levels of key
ingredient. But some firms object to testing method and defend
their brands' quality. Los Angeles Times, Aug 31, 1998.
This article was revised on April 16, 2000.
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