Tamoxifen and Antidepressants Don't Mix
Reader Comments
Best to check with your doctor or pharmacist, but...
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.
Tamoxifen and Genetics
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.
Pharmacies
I was informed by our mail order pharmacy, Medco, that I should no longer take Wellbutrin with tamoxifen. I immediately informed my oncologist and my OB/Gyn who were grateful, and somewhat humbled, to learn of this fact. My oncologist presented me with a list of antidepressants that did not interact with tamoxifen. I am presently on an SNRI, Pristique, which may help with the hotflshes, but I think my mood swings were better controlled by the Wellbutrin. After taking tamoxifen for 3 more years I may be able to shop around for a better antidepressant or not need one at all. I am very grateful to the pharmacists and Medco for alerting me.
Tamoxifen/Prozac
I am a Family doc who prides herself on being up to date on breast cancer. Yesterday I was humbled by a patient who told me of this interaction. I did not know. I have since researched it and am presenting the info to a bunch of other docs at our local tumor conference on Friday which will have a well known breast cancer specialist in attendence who can give us further info. The message is tell your own docs. It is the quickest way to spread the info. Thanks to Nancy!
what should you take with tamoxifen
I was diagnosed with breast cancer in dec 2006 and have been on tamoxifen and prozac for two years. Before cancer i took paxil for 5 years.
What do I take now. I can't take femara and I need an anti depressant for anxiety.
lw in GA
Tamoxifen and Antidepressants
I was diagnosed in 2002 with Breast Cancer. After a Lumpectomy, followup surgery and radiation I was on Tamoxifen for 5 years. A Psychiatrist, who specialized in cancer patients, put me on Lexapro. My oncologist was aware of this. I was on Lexapro (a low dose) the entire course of the Tamoxifen and longer. This news is very disturbing at this point. I'm approaching the end of my 7th year as a survivor. Still this report brought tears.
I realize that the medical community is constantly learning and discovering new treatments, but we patients are rendered helpless when guided incorrectly.
Proof that you need to advocate for your own health
As a breast cancer survivor and the co-founder of a non-profit dedicated to teaching women about breast health, I am disappointed but not surprised that this information apparently has been circulating for awhile and is still unknown by the very women it affects AND their doctors. It is just further proof that we all need to educate ourselves and advocate for our own health.
Money wasted ??
Kate is correct. There are plenty of safety nets built into the prescribing system to prevent the ordering of these drugs in combination.
It would be interesting to run the financial numbers. How many women have been on both drugs and the amount of money wasted because Tamoxifen was not effective. One article stated that essentially it was as if these women were taking a placebo
( Tamoxifen)under the above circumstances. I can only imagine what these women are thinking now.
Don't just stop taking them
Please ladies if you have been taking both Tamoxifen and an SSRI antidepressant don't just stop taking either medication. Talk to your doctor and find out if you are on a medication that requires weaning off of to avoid dangerous side effects.
I'm on Femara so this is not an issue for me but I can only imagine the terror of the women who were taking both medications.
It seems like there could be an easy resolution to this type of problem if pharmacists and even insurance companies flagged a prescription combination like this for further attention. Of course, that would only help those who are insured but it would be a start.
Kate@ http://www.aftercancernowwhat.com
This is old news but perhaps not
As a breast cancer survivor I was informed about this information 2 years ago from a breast cancer women's group where one of the members was a pharmacist and a breast cancer survivor.
Although I was not taking Tamoxifen nor anti-depressants it was amazing to hear those in the group who were unaware of the fact that Tamoxifen and Antidepressants Don't Mix. Many in the group were health care professionals who were also breast cancer survivors.
As a safety net wouldn't it be possible to have large pharmacies such as Walgreens or CVS place a stop or question the doctor before filling the combination of medications too??
Not only did these women not recieve the drug levels that they needed from Tomoxifen, this was a waste of money essentially. These drugs are not inexpensive.
