Colchicine .6

Why can't I eat grapefruit/drink grapefruit juice when taking this medication?

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In short, the grapefruit juice can affect the absorbtion of the drug into your blood stream such that it may enter the blood stream too quickly and/or reach unhealthy levels in your blood stream.

"Drugs that interact with grapefruit and/or grapefruit juice (GJ) undergo cytochrome p450 oxidative metabolism in the intestinal wall or liver. GJ contains various furanocoumarins which have been demonstrated to affect the cytochrome p450(CYP) system (especially at isoenzyme CYP3A4) by binding to the isoenzyme as a substrate and impairing first-pass metabolism, by direct inactivation or inhibition of the enzyme (mechanism-based inhibitors). The net effect on the CYP enzymes from this inhibition seems to be a selective down-regulation of CYP3A4 in the small intestine.26 For certain drugs which are known to be CYP 3A4 metabolized, less drug is metabolized prior to absorption, and greater amounts of these drugs reach the systemic circulation, leading to higher blood levels, and potentially to increases in therapeutic and/or toxic effects." [1]

Hope this info makes sense. Do you have any other questions or information to add? Please post back if you do...

Reference: [1] http://www.powernetdesign.com/grapefruit/general/mechanism.html

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Very cogent! Thanks.

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