Tamoxifen and Antidepressants Don't Mix

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I was told Lexapro was ok to go on and had to go off Wellbutrin.
I've been on Tamoxifen for 3 weeks and taking Lexapro. Now, I am not sure what to do! Any advice.

Debra Gordn of OH 7:23AM June 03, 2011

Can the women who were not ever informed by their oncologists, pharmacists, and other doctors about Wellbutrin's possible blocking action on Tamoxifen (like me, who just found out last week) create a group lawsuit because this is outrageous that they do not inform us. Seriously, isn't it more depressing to be dead because Wellbutrin blocked the tamoxifen than to be depressed because we can't take Wellbutrin? I think being dead of a variety of possible cancers is more depressing. I am seriously depressed now at the realization that I just wasn't important enough for anyone to care about enough to tell me about the possible conflict between the two drugs. My life just didn't matter. Why do we have to sit back and enjoy being guinea pigs for these drug companies? Can anyone tell me how to file a group lawsuit?

Not Informed of NY 4:28PM November 09, 2010

Medco just informed my family doctor, who prescribed Wellbutrin and my Oncologist, who prescribed Tamoxifen about the two drug interactions. I'm amazed with all of the literature out there that none of my doctors caught this. My surgeon, my oncologist, my family doctor, my OB-Gyn and my radiation oncologist all knew about the drugs I was taking and not one of them red-flagged this interaction.
My dilemma now is what do I take? I can't take the aromatase inhibitors. They cause terrible bone and joint pain so I'm back to Tamoxifen. But I NEED the Wellbutrin for depression, especially Seasonal Affective Disorder. With winter coming on I'm terrified of going off of Wellbutrin and becoming suicidal. Which is worse? Dying from breast cancer or dying from depression. Dead is dead.
Can someone help me find an antidepressant that doesn't interact with Tamoxifen? My family doctor's nurse just called today, Thursday and told me to stop taking Wellbutrin. When I explained that I couldn't she said I had to stop today and the doctor would call me on Monday. I didn't think I was suppose to stop Wellbutrin cold turkey. I'm not sure my family doctor is giving me good advice. Can anyone help me?

TrialAndError of OH 10:15PM September 16, 2010

To Susan Foxman of NY: Get off the zoloft. Paxil, prozac and zoloft have all been implicated in having the strongest effect on altering how tamoxifen works. If SSRI's work best for you, you can try to switch to either lexapro or celexa which have only a mild effect on tamoxifen; or you can switch to effexor (an SNRI) which supposedly has the most minimal effect on tamoxifen possible.
It is an infuriating situation to be in and I do understand, as I was recently diagnosed stage 1, node negative breast cancer and was strongly encouraged to take tamoxifen. Unfortunately, I happen to already be taking prozac, so I am in a situation not dissimlar to your own. I now have to make a decision about switching to lexapro or celexa (I tried effexor previously and it didn't work for me), or considering using an aromatase inhibitor, which I really didn't want to consider at all. But I will probably switch my anti-depressant because this is about reducing my risk of the cancer coming back!

sdm of CA 8:57PM July 19, 2010

Hi Loretta, How are you. I recently was put on Tamoxifen. I had Stage 11 Breast Cancer, Estrogen positive, no lymph node involvement. I chose to have a bilateral Mastectomy with Reconstruction Surgery. I also want to explore having a prophylactic removal of my ovaries. My younger sister died 2 yrs ago from this disease and never got the BRAC test, (I'm dumbfounded). My surgeon suggested I get it and the test came back Neg, but my oncologist said its' not a true neg because my sister was not tested for the gene mutation. Anyway off on a tangent,sorry. I take Zoloft for OCD Obsessive Complusive Disorder for yrs now and it was clearly stated in my chart. I accidently was researching something else and came across that certain anti-depressants can alater or just make Tam not work. Now this was 2AM, one opf my non- sleeping nights, I immediately called my Dr. who put me on hold. She ended uo telling my I was correct and to stop taking the zoloft right away. O.K. what do I do. I've been on this med for yrs. Had they told me during my chemo I could have been slowing weined off and put on a similar drug for my OCD. Thank God I found out on my own like you. Hope all is well with you. We must be our own advocates. Anytime you want to chat please contact me. Warm regards, Sue

Susan Foxman of NY 10:51AM June 05, 2010

Has anyone heard of a similar negative interaction between Prozac and Lipitor, where the lipid lowering effect of Lipitor got completely inactivated/obliterated when the patient started taking Prozac as well?

of MI 2:23PM April 18, 2010

I am a almost 4 years survivor of breast cancer(positive receptors). Chemo radiation etc. tamoxifen effexoe xr 150 my new doc wants me to try bioidentical progesterone because i am in adrenal gland fatige and cannot shake the weight. my cancer surgeon is going crazy beacause i (in his opinion) will not lose the weight. I feel as thought i am in a downward spiral. I do noty know where to turn or who to trust please help.

me of IN 8:11PM March 29, 2010

I recently went through surgery and radiation for breast cancer, and am now on Tamoxifen. Neither my pharmacist, nor my onco-doc, have warned me that taking Cymbalta, which they both know that I am on, could block the efficacy of the tamox. I researched this myself online and have come up with many studies and articles addressing this conflict. I mentioned it to my primary internist, he punched it inot his computer and said "I've got nothing on this." My question is why is this taking so long to get out in the medical world It is easy to find the info online, but my docs know nothing about it. Very frustrating.

loretta jacobs of CA 12:50AM March 19, 2010

Just because _some_ SSRI antidepressants inhibit CYP2D6, thereby retarding or completely inhibiting the bioactivation of tamoxifen, that doesn't mean that _all_ SSRI antidepressants do.
For example (and this is not exhaustive), Prozac (fluoxetine) and Paxil (paroxetine) are both potent inhibitors of the CYP2D6 drug-metabolizing enzyme. Zoloft (sertraline) is a weaker inhibitor of the enzyme. Finally Celexa (racemic citalopram) and Lexapro (escitalopram) both have much less of an effect on the enzyme. Wellbutrin/Zyban (bupropion) inhibits other CYP450 enzymes, but not (AFAIK) CYP2D6.

Steve Dyer of MA 8:31PM October 15, 2009

Tamoxifen works in the body when it converted into its active form called Endoxifen by a liver enzyme called CYP2D6. This enzyme is produced from the CYP2D6 gene on the chromosome. 7-10% of women with breast cancer possess a variant of that gene which results in very low production of the CYP2D6 enzyme.Tamoxifen is hence not converted into endoxifen and it accumulates in the body because it cannot be excreted properly thus causing adverse drug reactions.Women with this gene variant are scientifically called 'poor metabolizers' and are at increased risk of breast cancer recurrance as Tamoxifen does not work for them. Antidepressents which are often given to women to combat side effects such as hot flashes interact with the production of the CYP2D6 enzyme and result in lower than normal levels of the enzyme. Interactions between drugs administered to the patient as well interactions between the drug and the CYP2D6 gene must be carefully analyzed. Companies like Genelex in Seattle offer CYP2D6 testing services known as Tamoxitest, which can help determine the metabolizer status in women.

Sruti Mohandas of PA 1:43PM July 22, 2009