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Grapefruit, Orange and Apple Juices Block Drugs


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http://www.medicinenet.com/script/main/ ... ekey=92007


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Aug. 19, 2008 — Grapefruit, orange, and apple juices block drugs commonly used to treat infections, allergy, transplant rejection, cancer, and high blood pressure.

In 1991, David G. Bailey, PhD, and colleagues found that grapefruit juice increased blood concentrations of the blood pressure drug Plendil to possibly dangerous levels. Grapefruit juice, they later learned, slows down a key liver enzyme that clears Plendil — and about 40 other drugs — from the body.

Now Bailey reports that grapefruit, orange, and apple juices decrease the absorption of several important medications:

The allergy drug Allegra, available generically as fexofenadine

The antibiotics ciprofloxacin (Cipro, Proquin), levofloxacin (Levaquin), and itraconazole (Sporanox)

The beta-blocker blood pressure drugs atenolol (Tenormin), celiprolol, and talinolol

The transplant-rejection drug cyclosporine (Gengraf, Neoral)

The cancer chemotherapy etoposide (Toposar, Vepesid)

"This is just the tip of the iceberg. I'm sure we'll find more and more drugs that are affected this way," Bailey says in a news release.

Bailey revealed the new findings in a report to the 236th annual meeting of the American Chemical Society.

A substance in grapefruit juice called naringin seems to be the culprit. The compound apparently blocks OATP1A2, a transporter molecule in the gut, which carries some drugs from the small intestine into the blood. Orange juice contains hesperidin, a naringin-like substance. The culprit in apple juice remains unidentified.

"The concern is loss of benefit of medications essential for the treatment of serious medical conditions," Bailey says.

In their studies, Bailey and colleagues had healthy volunteers take fexofenadine with either a glass of grapefruit juice, a glass of water mixed with naringin, or pure water. Taking the drug with grapefruit juice or the naringin mixture halved the amount of drug that reached the bloodstream.

People should take their pills only with water, advises Bailey, a professor of clinical pharmacology at the University of Western Ontario, London, Canada. He suggests that people taking medications should check with their doctor or pharmacist before taking medications with fruit juices or whole fruits.

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(Medicine.net, Source: WebMD Article by David J. DeNoon, Reviewed by Louise Chang MD, August 19, 2008)


The information contained in these articles may or may not be in agreement with my own opinions. They are not posted as medical advice of any kind.

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Thanks for the posting, Barb.

I've been drinking apple juice almost every day since I was dx'd in 01/07. During that time my initial chemo was cisplatin/etoposide and I've subsequently taken both Cipro and Levaquin for chemo side-effect infections.

I also wonder if this might apply to some of the vitamin, herbal and mineral supplements i take with juices (and if it also holds true for juices other than grapefruit, apple and orange).


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Before reading this article, I had not given fruit juices a thought - except for the fact that with one of my own hypertension medications, I cannot have grapefruit juice. It interferes with its effectiveness.

Bill doesn't drink fruit juices. He likes green tea as a beverage and eats fruit as opposed to drinking juices. He drank it all through his chemo regimens, and his radiations.

This is the first time I have seen apple and orange mentioned in that way in any of the material in my purview.

Grapefruit has been known to be implicated in the processing of a certain antibiotic for quite some time now.


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