Grapefruit, orange and apple juices can harm the body's ability to absorb certain medications and make the drugs less effective, said a Canadian study released last week in the United States.

    The research showed that these juices can decrease the effectiveness of certain drugs used to treat heart disease, cancer, organ-transplant rejection and infection, "potentially wiping out their beneficial effects," it said.

    David Bailey, a professor of clinical pharmacology with the University of Western Ontario and leader of the study, was the first researcher to identify grapefruit juice's potential to increase the absorption of certain drugs two decades ago, possibly turning some doses toxic.

    The new findings came as part of his continuing research on the subject, and were presented at the 236th annual meeting of the American Chemical Society on Philadelphia, Pennsylvania.

    "Recently, we discovered that grapefruit and these other fruit juices substantially decrease the oral absorption of certain drugs undergoing intestinal uptake transport," AFP quoted Bailey as saying.

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

    Healthy volunteers took fexofenadine, an antihistamine used to fight allergies, along with either a glass of grapefruit juice, a glass of water with naringin (which gives the bitter taste to grapefruit juice), or plain water.

    Those who drank the grapefruit juice absorbed only half the amount of fexofenadine, compared to those who drank plain water.

    Researchers said the water with naringin served to block "a key drug uptake transporter, called OATP1A2, involved in shuttling drugs from the small intestine to the bloodstream."

    Among the drugs affected by consumption of grapefruit, orange and apple juices are: etoposide, an anticancer agent; beta blockers (atenolol, celiprolol, talinolol) used to treat high blood pressure and prevent heart attacks; and certain antibiotics (ciprofloxacin, levofloxacin, itraconazole).

    The drug-lowering interaction also affected cyclosporine, a drug taken to prevent rejection of transplanted organs, and more drugs were expected to be added to the list as the research continued.

    Bailey said patients should consult with a doctor about taking medications with juice, and stick to plain water when taking most medications.

    8月25日——柚子汁、橙汁、蘋果汁會損害身體吸收某些藥物的功能，從而降低藥物的功效。上周在美國發表的一篇加拿大的研究如此寫道。

    此研究表明，這些果汁會降低某些用來治療心臟病、癌癥、以及器官移植排斥和傳染的藥物的效力,

    潛在著消除藥物有益作用的可能。

    西安大略大學的臨床藥理學專家David Bailey，這次研究的負責人，是兩年前第一個證明柚子汁可能增加某種藥物吸收的人，可能會改變一些引起中毒的藥劑量。

    這個新的發現作為他在這個專題持續研究的一個部分，并且在賓夕法尼亞州費城的美國化學協會第236屆的年會上發表。

    “最近，我們發現柚子汁和其他果汁大大地減少某些口服藥物在腸道內攝入轉移的量。”支持Bailey的AFP如是說。

    “真正的擔憂是藥物失去了其對于治療某些嚴重的病情的本質優勢。”

    健康的志愿者服用fexofenadine，一種用于治療過敏癥的抗組織胺藥，分別用一杯柚子汁、泡柚皮甙的水和純水送服。

    研究者說，喝了泡有柚皮甙的水會阻礙了OATP1A2，這種物質有重要的藥物轉移功能，幫助藥物從小腸轉移入血液中。

    那些用柚子汁送服的對fexofenadine的吸收量僅為那些用純水送服的人的一半。

    受柚子，橙子，和蘋果果汁的消費量影響的藥物中有：依托泊苷，一種抗癌作用劑；β-受體阻滯藥（阿替洛爾，塞替洛爾，他林洛爾），一種用來治療高血壓和防止心臟病發作的；還有一些抗生素（環丙沙星，氧氟沙星，伊曲康唑）

    這種“柚子汁效應”也影響降低了用來預防器官移植排斥的環孢霉素的功效。隨著研究的進行將會有更多的藥物加入到這個列表中。

    Bailey說病人用果汁送服藥物時應咨詢醫生的意見，并且服用大多數藥物時應堅持用白開水送服。