Sat, 18 May 2002 13:09:14 +0200 in article
<a9dceukok0gbfufgodinon22htmjk069sa@4ax.com> cane
<cane219@yahoo.com> wrote:
>Hi, I've read that grapefruit juice increases absorption of
>some drugs. My question is : how much of 100% grapefruit
>juice should I drink to maximize absorption of following
>drugs: loratidine and arimidex. And when should I drink -
>just before taking drugs ? I appreciate any input.
>
As web page
Drug interactions with grapefruit. Clinical significance
http://www.globalrph.com/gfruit.htm
mentions, "Grapefruit juice is a potent inhibitor of the
intestinal cytochrome P-450 3A4 system (specifically: CYP3A4 -
mediated drug metabolism) which is responsible for the
first-pass metabolism of many medications." In other words
grapefruit juice may potentiate the effects of drugs
metabolized with the help of CYP3A4 enzyme. According to Ameer
et al. (1997) this inhibition happens in the small intestine,
so more of the drug will stay intact and get absorbed.
According to the web page
INTERACTIONS OF GRAPEFRUIT WITH MEDICATIONS http://www.ho-
listiconline.com/Herbal-Med/_Herbs/grapefruit-interaction-
s-home.htm
loratidine, however, does not appear to interact with
grapefruit juice. Also, I've been unable to find any evidence
that even Arimidex would interact with grapefruit juice.
In the case of the drugs which _do_ interact with grapefruit
juice, IMHO the simultaneous intake of grapefruit could lead
to drug overdose and should therefore be avoided unless the
prescribing doctor is aware of this and has adjusted the drug
dosing accordingly.
Links:
Grapefruit juice-drug interactions Home Page
www.powernetdesign.com/grapefruit/
Drug and Food Interaction Guide E-507 Alice Jane Hendley, Diet
and Health Specialist
http://www.cahe.nmsu.edu/pubs/_e/e-507.html
Food & Drug Interactions
U. S. Food and Drug Administration National Consumers League
1998 http://vm.cfsan.fda.gov/~lrd/fdinter.html
Medline:
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t=Abstract
-Matti Narkia