The non conformer's Canadian Weblog

August 20, 2008


Filed under: News and politics — thenonconformer @ 8:00 pm
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Juices may wash out drug effects London Free Press –   Consuming apple, orange or grapefruit juice can wipe out the benefits of some critical drugs, including cancer- fighting and heart medications, London scientists have discovered.  The groundbreaking research, presented at an international conference in Philadelphia yesterday, also found the common juices may block the transplant drug cyclosporine, possibly leading to organ rejection in patients.  “This is the tip of the iceberg,” said David Bailey, a professor of clinical pharmacology at the Schulich School of Medicine and Dentistry and the lead researcher.  Bailey said further research will find other classes of drugs that are neutralized by the consumption of juices.  Unless it’s known to be a problem, people should take medications only with water, preferably on an empty stomach, Bailey recommends.   Working with fellow Lawson Health Research Institute scientists Richard Kim and George Dresser, Bailey found the juices markedly depressed the absorption of certain drugs into the blood stream.  “The consequence of this is that the effect of the drug may be markedly reduced in its effectiveness and this can be a particular problem with some medications that are essential for the treatment of serious medical conditions,” Bailey said at the national meeting of the American Chemical Society.  The research did not look at juices beyond grapefruit, apple and orange, but it’s likely others will be found to have a similar effect, Bailey said.  He said he expects consuming the raw fruit itself will have the same effect as drinking the fruit juice.  For people who like to drink juices, the good news from the research is the depressing effect is relatively short-lived, allowing one to drink juice if they wait four hours before taking their medication with water.  “If you want to consume orange juice or apple juice or grapefruit juice, that’s fine. You just have to allow sufficient space between when you take your drug and when you drink the juice,” Bailey said.  The London research involved testing groups of 12 to 15 healthy volunteers with the antihistamine drug fexofenadine, used to fight allergies.  The volunteers were given the drug with either a glass of grapefruit juice or a glass of water.  When fexofenadine was given with the juice, only half the drug was absorbed.  Losing half the drugs taken into the body can be critical with some drugs, Bailey said.  In grapefruit juice, the researchers pinpointed the active ingredient naringin as the culprit in blocking the uptake of drugs.  In oranges, the chemical has been identified as hesperidin. The chemical in apples still hasn’t been identified.  While this research shows juices can reduce drug absorption, 20 years ago Bailey discovered grapefruit juice could boost a high blood pressure drug to dangerous levels, even if the juice was consumed a day earlier.  Yesterday, he said his finding that food could adversely interact with drugs was initially met with skepticism from many.  Other scientists have since identified 50 other medications that have a similar risk if consumed with grapefruit juice.  Some prescription drugs now carry warning labels against taking grapefruit juice.

Some fruit juices can harm drug absorption: study AFP
Juice blocks absorption of some drugs, study finds
The Canadian Press – – – Times Online
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