Wellbutrin (bupropion) and tamoxifen

By Jolene Boyd Friday, March 14, 2008

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Just wanted to post an update about my progress on my medication issue (i.e. my concern about anti-depressants in general, and bupropion for me specifically) inhibiting the metabolization of tamoxifen (and, as a result, potentially its effectiveness, as well.).

I met with my psychiatrist yesterday. She had booked an hour for me (almost unheard of for psychiatrists these days!) I brought a stack of the most relevant (my opinion) research articles about interactions between anti-depressants and tamoxifen and bupropion (the one I take) and tamoxifen. I also brought info about an oncologist at the Mayo clinic who is and has been doing research on these interactions, and the doctor-to-doctor consultation phone number that the Mayo Intake person had given me when I called Mayo a few weeks ago. After some discussion and review of the articles and some of my interpretations of the articles, she agreed that the possible interaction was concerning...enough so that she called and asked to speak to the doctor at the Mayo Clinic who is doing research on the topic. She pointed out that it was unlikely that she would get through and actually talk to him right then, especially without an appointment, but that she wanted to try it while I was there anyway.

Well, she DID get through and DID talk to him. The bottom line from the Mayo oncologist when my psychiatrist asked about taking bupropion with tamoxifen was something along the following: although the recommendations are based on currently unpublished research data at this point (i.e. they are so new they haven't gone to print yet), they (the researchers) do NOT recommend taking bupropion while taking tamoxifen. The Mayo oncologist said it DOES appear to be a strong inhibitor of at least one component of tamoxifen (endoxifen)...and it just so happens that it is one of if not the most important/beneficial component for reducing breast cancer recurrence. When asked about my experiencing hot flashes (i.e. wouldn't that mean it is having an effect?) he indicated that there are OTHER components of the tamoxifen that are metabolized by enzymes NOT affected by the bupropion, that could be causing the hot flashes. But that/those components are not what the researcher suggests is the most important component for blocking estrogen, which is the whole point of taking tamoxifen in the first place.

Well, my psychiatrist was convinced by this conversation that I need to get off the bupropion...ASAP. So that process has started. And today I also started a new anti-depressant, Effexor (generic: venlafaxine), which the research and the Mayo oncologist indicate is a only weak inhibitor and one of very few antidepressants that have been studied that are weak inhibitors rather than strong inhibitors. I assume that means there is still going to be somewhat of a reduction in effectiveness of the tamoxifen, but it should be much less of a risk than with other anti-depressants. No guarantee that it is going to do its intended job, either, but we can only give it a try.

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Comments (10) | Add comment

Maria Gifford, Editor

3/14/08 8:56pm

Hi Jolene,

Fantastic progress during your appointment today, I must say. Being "heard and validated" -- especially by getting through to a Mayo Clinic physician on the phone right during your appointment -- is phenomenal. Good for you, and kudos to your psychiatrist for picking up the phone and dialing the good ol' Mayo Clinic right here in Rochester, Minnesota (yes, I live here and worked for Mayo for a number of years.)

Best of luck with your change in medication. What a smart healthcare consumer and self-advocate you are. Be VERY proud of that.

Looking forward to hearing more from you soon. Stay in touch!

Best,

Maria

Anonymous

7/ 6/08 2:24am

Great post, I'm very happy to see you take that initiative. Because of you and your efforts many women will benefit. THANK YOU.

Jolene Boyd

7/ 6/08 9:17pm

You are very welcome... Just by way of an update, the first couple months on Effexor were a bit rough--mood stabilization seemed out of whack and I experienced bothersome side effects similar to what I have had with the SSRIs (primarily sexual side effects) but now the mood effects seem to be improving and the side effects are decreasing. Both are reliefs from my side of it!

My sense of my oncologist's opinion is that he thinks the research about the potential interaction between bupropion and tamoxifen is too new and the studies out there weren't very large, so he advised a more conservative, wait-and-see approach. That is still a bit disappointing to me, although I fully understand where he is coming from, from a purely "scientific" perspective. However, not to be overly dramatic, but when something can potentially affect cancer recurrence and therefore mortality, I think it makes sense to at least TRY another option if it's available. Which, of course, is what I did. I don't have any regrets at the moment!

Anonymous

11/21/08 9:08pm

This is disturbing as I am dependent on my Wellbutrin and have taken it for my two years of tamoxifen. My psychiatrist saw a mention of this concern in a medical journal the other day but it looked like the reference to bupropion might be a mistake because the article was about SSRIs and the article also cited an incorrect brand name for bupropion. Now that I see this and the resources you cite, I am a bit discouraged. She mentioned trying Effexor or nothing at all. Neither option is too appealing. Thank you for the information.

Jolene Boyd

11/30/08 3:00pm

I'm sorry to have brought you information that is upsetting--like we don't have enough to deal with already. I am encouraged that your psychiatrist is looking out for your health much as mine has been doing. Hopefully I can offer a little more information that might bring more support to you. First, I want to be VERY clear that my own oncologist thinks that it may be precipitous to make decisions about changing off of bupropion based on the research currently available--as your psychiatrist noted, virtually all the research involves straight SSRIs such as Paxil and Zoloft. However, bupropion (Wellbutrin) does appear to utilize the same metabolic enzymes as the SSRIs in the research, which is the same enzyme needed for tamoxifen to be broken down properly for greatest effectiveness. I might suggest that your doctor call the Mayo Clinic to talk to Dr. Goetz about his research if so inclined--there is a doc-to-doc consultation line for just this purpose: 800-533-1564. I did switch to Effexor--it seemed to be more or less effective for me but I had some side effects that I didn't with the bupropion (for me, primarily weight gain). Most people who have weight effects on Effexor actually lose weight, but I gained about 15 pounds in 3 months, which I has really bothered me since I have always kind of struggled with my weight and have been exercising and watching what I eat all along. My doc said it was likely the Effexor despite it being the opposite as the more common side effect-she said different drugs affect different people differently (how profound is that? Just kidding!)

But now there is a newer anti-depressant made by the same manufacturer called Pristiq (desvenlafaxine). Al lot of the stuff I read online suggested that it was just a way for the drug manufacturer to make more money because the patent on Effexor expires this year or something so other companies can start producing generic versions. But here is the thing my doc discovered-Pristiq apparently isn't metabolized by the enzyme tamoxifen needs at ALL, meaning there should be no interference with (and hence hopefully no reduction in effectiveness of) the tamoxifen. Otherwise it is VERY similar to Effexor. Thus far, things seem to be going ok for me-I have been on it about 2 months now, starting at 50 mg with an increase to 100 mg daily after 6 weeks (was noticing trouble with concentration, motivation and quick to cry.) Again, so far, so good--seems like there has been an improvement in those areas and I'm keeping my fingers crossed because I have dropped a couple of pounds already, too. Please share this information with your psychiatrist and see what she thinks. You can find some FDA info on Pristiq at http://www.drugs.com/pro/pristiq.html.

I sure hope this is helpful-don't give up-I wasn't thrilled about changing myself but it hasn't been too bad. Also, please note that there are no guarantees on any of these things and what I decided to do may not be right for anyone else, of course. My oncologist points out that you have to often weigh the potential benefits vs. the potential risks and then make the best decision you can. Good luck and let me know if I can be of any more assistance. Jolene

Not Informed

11/ 9/10 3:54pm

Neither my oncologist, nor my psychiatrist, nor my pharmacist told me anything about the fact that wellbutrin can cause the tamoxifen to not be absorbed by your body. Are they not required by law to give us such information. Isn't that what informed consent is about? What can people who weren't told do? Is there legal recourse?

PJ Hamel, Health Guide

11/ 9/10 5:05pm

They may simply not have known. I don't think doctors are required by law to keep up with all the latest research (though it would certainly be helpful). Have you asked anyone on your medical team about this, now that you have a starting point for a discussion? PJH

no name

2/ 6/11 1:26am

My surgeon said nothing about mixing the two drugs. Neither did my PCP. So, I asked my PCP when I saw him last week if it was okay to mix the two. He didn't know and looked it up, and sure enough, it is not okay to mix them.

If I hadn't brought it up, I would have started to take the Tamoxafin thinking it was giving me the full benefit of the drug.

Now, I have to ask my surgeon if I can go on another anti estogen drug.

PJ Hamel, Health Guide

2/ 6/11 6:42am

Unfortunately, there's no real substitute for tamoxifen, if you're pre-menopausal. I hope you're able to discuss this with your oncologist, rather than your PCP; the oncologist is the one who should be advising you on medications, at this point. Hopefully s/he has some experience with this issue, and will be able to make some recommendations. Take care- PJH

Jolene Boyd

2/ 6/11 11:57am

I am 3.5 years into remission, and took Wellbutrin and tamoxifen for a period until my own research led me to ask questions about the combination of my oncologist, who sort of blew it off (research is preliminary, utilizing small sample sizes, etc.) I wasn't satisfied with his "disinterest", so I then asked my psychiatrist about it, and she took it VERY seriously, contacting one of the principle researchers on the interaction between these two specific drugs at the Mayo Clinic, who suggested that if it were HIS patient, he would advise her to find something else to take other than Wellbutrin. Long story short, that is what I did. Mind you, I had already tried a number of other antidepressants--the SSRIs (selective serotonin reuptake inhibitors, like Paxil, Zoloft, Prozac) never seemed to quite cut it for me. Wellbutrin also inhibits the reuptake of dopamine and norepinephrine, along with serotonin. But the SSRIs are well-documented as also interfering significantly with proper metabolization of tamoxifen, so what next? Effexor is a SNRI (serotonin & norepinephrine reuptake inhibitor) that has shown a weaker interaction effect with tamoxifen, but Pristiq (also a SNRI) is actually metabolized by the kidneys, rather than the liver, and thus it doesn't seem to interfere with tamoxifen metabolization (which is needed in order for the body to get the estrogen-blocking benefits from tamoxifen.) I personally have had better success in managing my mental health symptoms using Pristiq than with any of the other antidepressants (including Effexor, which is chemically very similar), but it still is no match for Wellbutrin. As with so many other things we face after being diagnosed with breast cancer, this is one more choice where each person has to way the potential benefits vs. the potential risks and make the best-informed decision s/he can. For me, I am simply biding my time (1.5 years to go!) until tamoxifen treatment ends and intend to switch back to Wellbutrin ASAP after that! I see a psychiatrist and therapist on a regular basis to help me maintain the best mental health possible in the meantime, which I would suggest for anyone who decides to change their medication after successful treatment with Wellbutrin (or any of the others, quite frankly). In the end, it is always up to each of us to fight for what we think is important and best for our health long-term. Hope that helps a little.

Wellbutrin (bupropion) and tamoxifen

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