Tamoxifen and grapefruit/juice

Options
Anonymous
Anonymous Member Posts: 1,376
edited August 2020 in Hormonal Therapy - Before, During, and After

Hi all,

Just sharing. I talked to my pharmacist this morning and he confirmed that grapefruit and or grapefruit juice interact with Tamoxifen, making it less effective. I used to eat it every day (as of yesterday) but won't anymore darn it.

It may have been on the package insert for tamoxifen but I probably didn't read it. I'm glad I checked in here and found that there seemed to be some concern about this issue.

He said other citrus fruit doesn't have the same enzyme so they are okay.  

He also said eating half a grapefuit a month probably would be alright.

Claire

· Share on FacebookShare on Twitter

Comments

  • geewhiz
    geewhiz Member Posts: 1,439
    edited April 2012

    Thank you for sharing that with us!!

    · Share on FacebookShare on Twitter
  • jancie
    jancie Member Posts: 2,631
    edited April 2012

    If you go to www.drugs.com you can use their interaction checker to see all of the OTC and prescription drugs that interact with Tamoxifen.  You might want to do this as the list is HUGE!

    Simple things like Benedryl, etc. interact with Tamoxifen.

    · Share on FacebookShare on Twitter
  • peggy_j
    peggy_j Member Posts: 1,700
    edited April 2012

    My understanding is that grapefruit changes the rate at which your body absorbs tamoxifen and many, many other medications. (including common medications, like ones for high blood pressure.) Not sure why the pharmacist is saying that it's ok to eat a half a grapefruit once a month. If you really can't live without grapefruit, perhaps a better strategy would be to eat it after your know the tamox is fully absorbed. (2 hrs? 6 hrs???) I'd ask your doc. Personally I just skip it.

    Edited to add: This source (below) says

    "One standard glass of grapefruit juice is considered enough to cause significant impact to the metabolization of certain medications, especially if taken within four hours of each other, but the effect may last up to 24 hours. This interaction is particularly dangerous if the medication has a low therapeutic index, which means that small increases in dosage quickly become toxic. Grapefruit juice only affects the enzymes in the intestines and not those in the liver, so injected drugs are not a concern."

    http://www.livestrong.com/article/445135-does-eating-grapefruits-affect-medications/ 

    · Share on FacebookShare on Twitter
  • Anonymous
    Anonymous Member Posts: 1,376
    edited April 2012

    Peggy J, I asked him if I could take the tami at night and eat my grapefruit in the morning...he said no. So it's off my radar of foods for at least five years...

    He said that it is an enzyme-metabolic reaction, as you've captured.

    I knew about the benedryl already, and started checking further, b/c of the postings here. I don't know if I would have found it otherwise since my onc. never told me about interactions.  

    It pays to be proactive about your health. No one is a better advocate for your health that you...

    Claire

    · Share on FacebookShare on Twitter
  • peggy_j
    peggy_j Member Posts: 1,700
    edited April 2012

    Good to know that the pharmacist thinks taking tamox at night isn't enough. I'm sticking to my no grapefruit plan.

    FWIW, when I asked my MO about food interactions, she referred me to her nutritionist, who sent me a 20+ page printout from her database. For each substance that might have an issue, it gave the severity of the interaction and graded how solid the evidence was. Maybe you have access to a nutritionist who can share that same info? Some books list possible interactions. In one, I found that licorice root has a contraindication with tamox. So much for many of my favorite herbal teas! There have been other discussions here on various threads (often in the complementary forum), but it's nice to have one solid source.

    · Share on FacebookShare on Twitter
  • kcjules
    kcjules Member Posts: 4
    edited July 2020

    I will be starting Tamoxifen in August. My pharmacist husband said I am going to have to say goodbye to my daily morning grapefruit. I met with my oncologist on Monday and she said I can just take it at night and I will be ok. Everything I have read says not to take it at all. So, to err on the side of caution I will be stopping my grapefruit consumption in a week. After 15+ years of a daily grapefruit this will be hard! I might see if once a month will be ok just to get my fix.

    · Share on FacebookShare on Twitter
  • Lumpykins
    Lumpykins Member Posts: 14
    edited August 2020

    Boooooooo! I love grapefruit and grapefruit juice. Just started Tamoxifen today. Would have had grapefruit yesterday if I'd known I wasn't gonna have any for FIVE YEARS.

    · Share on FacebookShare on Twitter
  • quinnie
    quinnie Member Posts: 221
    edited August 2020

    Oh No, I wonder if it is the same with Letrozole. I enjoy my occassional grapefruit juice with vodka!!! LOL

    · Share on FacebookShare on Twitter

Categories