The Goods on Grapefruit and Medications that Won’t Mix

Suzy-CohenDear Pharmacist,
My medication label suddenly warns not to eat grapefruit, but is this a serious interaction? Reason I ask is because I love to eat it, and nothing has happened to me so far.  –K.A., Tulsa, Oklahoma
Answer: Then stay consistent with your eating habits because consistency allows your doctor to adjust medication dose based on eating habits. Momentarily, I’ll tell how this incredible fruit can help you lower cholesterol, burn fat and reduce cancer risk, but first I  I must warn you that grapefruit prevents proper break down of some medications, causing blood levels to spike. This may happen even if you separate administration of the drug from the fruit or the juice by days. Soon enough, I will give you a list of drugs to avoid if you won’t give up the grapefruit. I wouldn’t blame you either, I love grapefruit myself. The seeds are the primary source of naringenin, which is the bitter chemical that causes the pucker. It’s also a strong antioxidant that not only neutralizes free-radicals (which promote cancer) but also seems to prevent hardening of the arteries.
Grapefruit may boost metabolism, at least in rodents. Thin rats don’t necessarily translate to thin thighs, although I still think grapefruit is a fine edition to most diet plans, especially those that include ways to help you improve progesterone to estrogen ratio, and increase thyroid hormone. Grapefruit may help people with diabetes or metabolic syndrome (high cholesterol, blood pressure and blood sugar). 

Naringenin is not an appetite suppressant, or a fat blocker so if you take those dietary supplements, it’s also fine to take this bioflavonoid supplement. It can be combined with protein supplements too, which are often recommended during weight loss.

You’ll see it listed in various ways, including naringenin, grapefruit seed extract, GSE or part of a comprehensive bioflavonoid formula that also contains hesperidin, rutin or quercetin. These types of products are widely available at health food stores.

Before you get too excited and buy supplements or fresh fruit at the grocery store, I need you to promise me that you’ll get both your physician and pharmacist’s approval (and it wouldn’t hurt to research yourself) to find out if grapefruit, or grapefruit-containing supplements are right for you.

The approval from both your doctor and pharmacist  is important because I don’t have the space to list all of the drugs that might potentially interact. The following drugs (and possibly related drugs that are not listed here) may have a potentially dangerous interaction with grapefruit, so never combine it with these: Sildenafil (Viagra), buspirone (Buspar), sertraline (Zoloft), triazolam (Halcion), diazepam (Valium), carbamazepine (Tegretol), cyclosporine, tacrolimus, felodipine, nifedipine, HIV medications, statins cholesterol drugs (simvastatin, atorvastatin, lovastatin), amiodarone, methadone, digoxin and losartan (Cozaar).
Did You Know?
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  1. Carol A Phillips July 2, 2010 at 4:54 pm - Reply

    Dear Suzy,
    Does this warning include grapefruit seed extract? I often recommend it to different friends of mine with infections, flu, etc. and would like to know whether this is included. It is very effective for what I use it for and recommend it for.

  2. Jay July 4, 2010 at 1:33 pm - Reply

    Hi – I take Losartan. Is there a location telling me what foods not to take?

    Many thanks

  3. R.W. July 5, 2010 at 11:20 pm - Reply

    Am takeing 40mg of simvastatin Love grapfruit and eat it once in a while, not every day. does tht make a difference?

  4. Dave M. July 23, 2010 at 12:21 pm - Reply

    I take 50mg Metoprool twice a day will grapefruit taken be okay.Thank you

  5. Nancy July 30, 2010 at 12:27 pm - Reply

    Hi Suzy,

    I have thus far refused statin drugs but do take 1200 mg of Red Yeast Rice (RYR) daily. I also take Valerian for sleep aid. Is grapefruit harmful when using RYR or Valerian?

    Thank you,


  6. Ian Shaw July 31, 2010 at 7:52 am - Reply

    You know the study involving the effects of grapefruit on circulating statin levels did not relate to eating half a grapefruit in the morning. Study participants drank a quart of grapefruit juice. And what was the effect? The statins metabolized more slowly. Was this detrimental? Actually no, it allowed for a reduction in the dosage while producing the same effects. Good for us but bad for pharmaceutical companies. Doctors should prescribe baby doses of statins along with a daily glass of grapefruit juice to reduce the amount of statin we need to ingest to get the same results.
    If you are going to publish advice, please read the original research. Anyone can parrot what they read from a drug manufacturer’s info sheet.

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