Tamoxifen Side Effects: Brain Fog and Dizziness?

Oh my gosh ladies I am so sorry as it’s incredibly frustrating to feel like you’re not being heard by your team. You know your body best, and it’s absolutely fair to question what’s happening when something changes right after starting a new medication. Tamoxifen and aromatase inhibitors (like Letrozole) are far from perfect, and the side effects can be very real. Brain fog and feeling like you’re going to pass out aren’t the most common reactions, but that doesn’t mean they’re not caused by the drug. Just because it’s not in the top five side effects doesn’t make it less valid. You deserve better answers and more support. That said, I want to share this context because it’s really important: for people with early-stage (even small tumors with no lymph nodes involved) HR+ breast cancer, the risk of recurrence over 10 years without endocrine therapy can be 20 to 30 percent! Taking tamoxifen or an aromatase inhibitor can lower that risk by about 40 to 50 percent. That’s not a small difference. When breast cancer returns as metastatic disease, it is no longer curable. That’s the reality. It can be managed, sometimes for years, but until research results in a cure it is terminal. None of this means you have to tolerate side effects that make you miserable. There are different drugs, different doses, and ways to manage symptoms. It’s worth having a care team that helps you make informed decisions instead of brushing you off so switch oncologists if you need to! Wishing you clarity, support, and better care moving forward. You deserve that. I’m so glad you are both a part of our community. 💛 Suzanne (Community Moderator)

I am so glad that the moderator chimed in. I was having overwhelming dizziness with another medication and did not get a valid answer from 2 sources. I was told that I had to take time to get used to it. I felt that the 2 meds I take (both had dizziness side effects} we're interacting and both told me I could take together...really? When I finally talked to my doctor he immediately changed the medication. Listen to your body..you know best. So far be so good!

Holly, No one listens in right!

Thank you all for the comments. Ty Suzanne for keeping it real- I needed that reality check. It does make me feel better.

I’ve been on Tam for almost a year now. I had both of these side effects when I started. I would say they both subsided. I would say the fainting feeling went away at about a month and the brain fog maybe at 2. I had a terrible racing heart for about the first 2 weeks as well. I have neither now (except for being older brain fog ) try and push through and hopefully it gets better for you.

Wow Ty vm! I greatly appreciate that

Many people taking tamoxifen do experience these challenging side effects, including brain fog and dizziness, so you're definitely not alone in dealing with this. It can be really frustrating when you feel like your concerns aren't being fully heard by your medical team. While working with your doctor to figure out the best approach is important, connecting with others here who may have similar experiences could provide helpful insights and support during this difficult time.