Unable to tolerate tamoxifen.
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To sk06 - Thank you so much for taking the time to respond and answer my questions! I really appreciate your sharing, especially since this is the next decision (really the only one I'll have to make regarding my treatment - since lumpectomy, radiation, and chemo were just a given). Gosh, I am so sorry that you had to go through this starting at 34, that is so young and amazing that you caught it. It seems as though the side effects are all over the place for different people, and unless there is some discriminating factor, I'm just going to have to pick something and start from there, and hope my MO is patient enough to find something that's tolerable.
Earlier in this thread, I mentioned that I suspected that I may have a CYP2D6 gene defect that would effect my ability to metabolize tamoxifen - so would have been taking it, and it wouldn't be working. The CYP2D6 enzyme breaks down as many as 25% of all prescription medication. So any variations could lead to being under or overdosed. So perhaps you were an ultra metabolizer and getting too much of the medication?0 -
@Tinyfrog, Yes, I do remember a nurse practitioner telling me something about me possibly not having a particular enzyme or something, that might be making it hard for me to metabolize tamoxifen properly. That could have been it. I remember feeling very VERY sick on it. I would get horrible vertigo, and I almost felt like I had just gotten a chemo treatment it was so bad. Had the same nausea, dizziness, fatigue etc. Felt like I was being poisioned or something. It didn't do well on the AI's, but Tamoxifen PARTICULARLY was way WAY worse for me. If I personally had to 'choose' what to 'start with', it would certainly be one of one of the AI's, and Tamoxifen last. Of course, that is just because of my personal experience with it. I know some people that tolerate tamoxifen fine, so it is always so hard to know. The doctor said that my SE's on the AI's etc, are so bad because it is most likely because I am 'younger'. So, I have a lot of estrogen still in my body, and the drop from the AI's causes worse side effects that someone who is older. I am doing the shot ONLY right now because that seems to be all I can tolerate at the moment, because my doctor wants 'to so something', so that is where we are at. Make sure to tell your doctor of all of your symptoms etc, and they can switch you from one to the other, and perhaps you will fine which AI works best for you. !!
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Does anyone know why some people are on the 5 year plan versus some on the 10 year? Does it have something to do with whether or not you've had chemo? Only 5 years have been mentioned in my case thank goodness, just wondering though.
I read there were 3 SERMS: tamoxifen, Evista, Fareston. I've read that someone was on Fareston. Anyone on Evista?
To sk06 - I had also come to some assumption similar to what your nurse had said regarding the AI's, as that same logic probably applies to how severe my hot flashes were from the chemo effecting my ovaries, but now luckily, I have a respite from chemo SE. However, in your case if age had been the driving factor in your reactions, then it doesn't make sense that you're able to tolerate lupron over tamoxifen. Tamoxifen gives you menopause symptoms but doesn't actually put you in menopause, but ovarian supression actually does?
"Ultra-metabolizers who have gene amplification at CYP2D6 will hyperconvert tamoxifen to the potent metabolite endoxifen, and will typically find tamoxifen intolerable. In theory they could pursue dose titration, but given limits on pill size and availability of good alternatives, will generally switch to AI's."0 -
I'm an ultra-rapid metabolizer of Tamoxifen. The pill has no side effects on me at all. Getting this enzyme test is truly not a predictor of who will be able to tolerate Tamoxifen. It's more a test for if the Endoxifen levels will be Therapeutic. Being a poor metabolizer means you will need more Tamoxifen to reach therapeutic endoxifen levels. I'm happy I was an ultra-rapid, they get the most benefit from Tamoxifen.
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do this thread is older, but made me feel better about my tamoxifen experience. I had a massive headache from the day I started until after I stopped it, nothing helped the headache, it was awful, then I started having nightmares... That's when I called my doc. He said stop taking it now. I got a one month med vacation and just started Evista. So far so good, third day only a mild headache and mild nausea plus a little tired, but I imagine theses will get better once my body gets used to it. I am premenopausal and he told me this is really my only other option, so I hope I tolerate it.
I don't see much about Evista, anywhere, it must not be used much because they seem to give everyone tamoxifen.
Bonus is it helps strengthen bones.
Good luck to you
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Hi Grammieshell - Thanks so much for the input. I've only done light researching, and I was getting really excited and completely sold when I was looking at Evista as an alternative since it had reduced serious side effects (clots, uterine cancer) also hot flashes, and was cost effective. But my heart sank when I read it doesn't protect against lobular or DCIS, which I had multiple sites of. It would still be an option for me if I couldn't tolerate anything else, because it does offer protection from invasive, which I also had multiple sites of. I'm glad to hear so far so good for you. Wouldn't lupron and/or AI also be an option, but probably not if side effects were worse? Also, if Evista doesn't work out, someone else was on another SERM called Fareston, which is normally given to post-menopausal women, but there are some small recent studies in pre-menopausal. But it's also expensive. Thanks so much for your feedback!
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