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Anti-aging Research > Cytochromes.
Cytochromes - American Academy of Family Physicians
Cytochromes - emedicine.com
Cytochrome - familydoctor.org
Books on Cytochromes - Amazon.com
News & Research:
St John's Wort Alters Enzymes Involved in the Metabolism of About 50% of
Over-the-Counter and Prescription Medications
- Doctor's Guide, 9/18/03 - "long-term administration
of St John's wort may result in diminished
clinical effectiveness or increased dosage requirements for all CYP 3A4
substrates, which represent at least half of marketed medications" -
The way I understand it, the enzyme that SJW increases protects the liver.
JAMA always seems to be biased against supplements, which might be why they
didn't mention that. Have they ever mentioned the
pitfalls of prescription drugs?
- St. John's Wort
Increases Metabolism Via CYP 3A4 - Medscape, 9/16/03
What should I know about drug interactions with St. John's wort? -
Natural Foods Merchandiser, 4/03 -
"One activity of St. John's wort, probably
independent of its mood-altering actions, is increasing the CYP3A4 enzyme
activity of liver and intestinal-wall cells"
- Why should one avoid
grapefruit when taking Valium or a cholesterol-reducing medication? -
Dr. Weil, 3/28/03
Cholesterol Metabolism May Provide Alzheimer’s Clue - Psychiatric Times,
"The CYP46 enzyme regulates levels of brain
cholesterol, researchers believe, through a feedback mechanism that allows
the amount of soluble cholesterol leaving the brain to match closely the
amount of cholesterol that is normally synthesized or routinely recycled
(through APOE) within the brain. The end result, under normal conditions, is
a fairly constant level of cholesterol in brain tissues"
Smoking-Related Anti-psychotic Dose Adjustment Could Improve Response -
Doctor's Guide, 3/10/03 -
was largely metabolised by the cytochrome P450 enzyme CYP1A2. Smoking
powerfully induced this enzyme's activity"
FDA Looking for Grapefruit Interactions - Doctor's Guide, 9/23/02 -
"If a drug has a large first pass effect, consuming
grapefruit could cause a higher drug dose to enter the bloodstream through
any of these actions ... Two drugs Dr. Piazza-Hepp cited as coming recently
under suspicion are amlodipine, a
calcium channel blocker, and atorvastatin"
St. John's Wort: Effective, with Caveats - Nutrition Science News,
Spring, 02 -
"The cytochrome P450 system is a set of enzymes used
to break down many substances in the liver. Scientists have recently found
that hyperforin, hypericin, and biapigenin activate five of the key
cytochrome P450 enzymes.10 ... Of the P450 enzymes, CYP3A4 is one of the
most important—involved in the breakdown of more than 50 percent of all
pharmaceutical drugs currently used.2 Treating human liver cells with
hyperforin dramatically increases CYP3A4 activity. Thus, hypericum extracts
are likely to interact with more drugs than expected"
- Hypericum, Drug
Interactions, and Liver Effects - Medical Herbalism, Medical Herbalism
"The specific enzyme system whose activity was
increased in the test subjects is the CYP3A, part of the p450 microsomal
enzyme system, responsible for Phase I detoxification in the liver"
Characterising Fluvoxamine Metabolism - Doctor's Guide, 4/19/02 -
"the higher fluvoxamine doses inhibited CYP1A2 and
CYP2C19 by approximately 75 to 80 per cent. The inhibition with the lower
doses was around 40 to 50 per cent"
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