DEAR DR. ROACH: Some prescription medications have a warning that they may have an interaction or reaction to grapefruit. Is it dangerous to continue to eat grapefruit even if you’re on these meds, or is that an overreaction of some kind? I love grapefruit, and it’s really hard to give it up. — D.K.
ANSWER: I can’t answer this for every possible drug. Grapefruits and grapefruit juice (and a few other less-common citrus fruits) inhibit one of the enzymes used by the liver to detoxify drugs, called CYP3A. This enzyme is used in the metabolism of dozens of drugs. In most cases, it increases the drug levels.
Often, this is not a big deal. Most of the drugs we use have low toxicity, and people tolerate a slightly higher blood level due to grapefruit products. However, some drugs, especially those that work on heart rhythms (like amiodarone), immunosuppressants (including cyclosporine, tacrolimus and other related drugs), and chemotherapy, are at a high risk for a drug interaction with even one grapefruit or glass of juice daily. Your pharmacist can look up your prescription medications to tell you if there is a potentially dangerous interaction.
DEAR DR. ROACH: Gallbladder disease runs in my family. Two of my grandparents, my mother and three of my four sisters, including me, have all had our gallbladders removed.
Several of us have had some lasting problems post-surgery — namely diarrhea. A friend recently told me that she has had success with the supplement choline. Is this something you have heard is helpful? Is there any risk to taking it, and is there a safe dosage? — S.N.
ANSWER: Choline is indeed a supplement I have seen people take. It is usually marketed to “help memory,” although there is not very good evidence to support it. I have not seen choline marketed for treatment of post-surgery diarrhea and don’t know why it would work.
I wonder if your friend might have confused two drugs with similar-sounding names, ones that I frequently recommend for diarrhea following gallbladder surgery: cholestyramine and colestipol.
The main job of the gallbladder is to hold and release bile acids, which help us properly break down and absorb fats. Without a gallbladder, bile acids are released continuously by the liver into the small intestine. Bile acids are reabsorbed at the end of the small bowel and reused. If too many bile acids go all the way through the small intestine into the colon, diarrhea occurs.
Most people’s small intestines are able to increase their absorption of bile acid within a few weeks or months after surgery. So the diarrhea does go away, but with other people, it can be a long-term problem.
Both of the prescription drugs mentioned before work by binding the excess bile acids, and my experience with a few patients (and in letters from a few readers of this column) has shown that these medications can be life-altering. I recommend having a discussion with your surgeon or regular doctor about a trial of one of these medicines for those in your family with persistent diarrhea after gallbladder surgery, but I don’t recommend choline supplements, which can often cause diarrhea.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.
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