On Tamoxifen: Sharing My Patient Experience

I was prescribed tamoxifen after my lumpectomy. Tamoxifen is a recommended medication for those who have had a breast cancer diagnosis in the past or are considered high risk for developing breast cancer. I want to share my experiences with tamoxifen with you so that you can have an idea of what it might be like to be on this medication.

Please Note: I am not a doctor or a medical professional, and I am not offering medical advice in this post. Please follow the advice of your medical team, and understand my disclaimer before continuing.

What is Tamoxifen?

Tamoxifen is one of the endocrine therapies that may be prescribed to patients after a breast cancer diagnosis. It is usually prescribed to pre-menopausal women, and the duration prescribed can be either 5 or 10 years. If a woman is post-menopausal, then another class of medications, called aromatase inhibitors, can be prescribed.

These endocrine therapies are designed to reduce the likelihood of cancer returning. If your breast cancer was hormone receptor-positive (Estrogen Positive), then these medicines will remove the “food”- the estrogen- that cancer feeds on.  

Tamoxifen is a Selective Estrogen Receptor modulator. It blocks the effects of estrogen on breast tissue while activating it in other body tissues.  

It is an oral medication that is taken once daily to reduce the risk of breast cancer.

My Fears About Taking Tamoxifen:

I had many concerns about taking tamoxifen. I researched the potential side effects, and I brought my worries to my oncologist during the prescribing appointment.

He listened and addressed each of my concerns one by one. Then, as we were closing up our conversation, he gave me some encouragement. He said, “You can start taking it and evaluate the side effects. If they are too much for you, you can stop taking it.” 

Those words gave me the agency I needed to give tamoxifen a try.

What Were My Experiences With Tamoxifen?

I started taking tamoxifen after I had completed my radiation treatment. I could have started before radiation, stopped for radiation, and then continued. I decided to avoid stopping and starting by waiting until I was done with radiation.

I’ll share some of my side effects and experiences here. Everyone reacts differently to medication, so your experiences might be different.

Hot Flashes: These came on almost immediately. I would wake up in a sweat in the middle of the night, especially if I was wearing fleece pajamas! I quickly found out that I needed to sleep in light microfiber pajamas so that I didn’t wake up soaking wet. I would also have trouble regulating my temperature during walks. I was either too hot or too cold. After a few weeks on tamoxifen, they settled down and weren’t noticeable for me.

Mood Swings: I was really volatile during the first few months of Tamoxifen. I’m not sure if it was all due to the drug or if some of the mood challenges were due to my recovery from surgery and radiation. I got angry quite a bit, and there was a lot more yelling going on when I started it. My kids noticed the mood swings and commented that the pill was making me crazy.

That didn’t help at all! I ended up sitting the family down and going over with them how hard it was to keep my emotions in check, but that I was taking this pill to try to prevent a recurrence. I asked them to stop blaming my moods on the tamoxifen. After a couple of months, I realized that my moods had become more even, and I wasn’t struggling to deal with them as much.

Vaginal Dryness and Discomfort: This pill dried me up. Suddenly I was raw, and intimacy was really uncomfortable. I ended up seeking specific help from my gynecologist for this issue. She recommended some lubricant creams and worked with my oncologist to prescribe local estrogen cream.

I ended up sticking with the OTC lubricants because I found one that worked for me. This was a challenge because I was allergic to something in the K-Y lubricants. I ended up using the lubricant by Lola. It was definitely a trial and error to figure out what was going to work. 

No Sex Drive: I’m not sure if it was the dryness, the lack of hormones, or the post-cancer stress, but my sex drive was not around. I needed to work extra hard to get in the mood.  

Sleep Challenges: I had trouble sleeping, which could have been due to the residual anxiety from cancer or the hot flashes. I tried to establish a relaxing bedtime routine so that I could have a better chance of getting a good night of sleep.

Crazy Periods: So, one of the fantastic benefits of tamoxifen (insert sarcastic tone ) is that I got the side effects of menopause, but with the benefit of still having a period. Additionally, I would have no idea when my period would start. Usually, I can tell when my period is coming because my breasts swell. But not on Tamoxifen. There were a few months when I needed to do extra laundry because my period showed up and I wasn’t prepared….

Decreased Breast Size: My breasts were noticeably smaller on Tamoxifen, especially my left, which was the non-treated side. It looked like a deflated balloon. 

Why Did I Stop Taking Tamoxifen? 

I had been on Tamoxifen for about nine months and was dealing with all of these side effects. They were manageable. Not pleasant, but manageable. I felt like I had gotten over some of the worst side effects and would be able to make it for the full treatment length. Then, something else cropped up.

Rib Pain: After about 9 months, I noticed that I was having pain in my lower right ribcage. It was like I had gone running and had a stitch in my side. It would show up for me in the afternoon and get worse towards the evening. It was beginning to impact my sleep. I mentioned it to my oncologist during our appointment, and he initially thought it might be a muscle strain from working out.  

He recommended I take some pain relievers and keep an eye on it. I did that and slowed my workout routine down. The pain didn’t go away. I was beginning to think that it might be something else.

I decided to do some research on the rare side effects of Tamoxifen. It turns out that pain in the lower rib area can be a side effect and that I should contact my doctor with the symptoms. 

I messaged my oncologist with my concerns, and he suggested I take a couple of weeks off of the drug to see what would happen. I did that, and the pain went away. I went back on it, and the pain came back.

My oncologist decided that I should stop taking it. While the drug will reduce the likelihood of the cancer returning, it didn’t have a lifesaving benefit for me with my DCIS diagnosis.  

So, I stopped taking it after 11 months.

This wasn’t an easy decision to make. Tamoxifen has been well established to reduce the risk of breast cancer returning. I wanted to be “a good patient” and stay on it. I struggled with the choice I was making. However, my quality of life was definitely being diminished with the rib pain.  

I’m grateful that my oncologist listened to my concerns about Tamoxifen. He helped me have the strength to start it and see what happened. Then, he took my side effects seriously and weighted the lifesaving benefit of the drug. My doctors’ goals have been to remove the cancer and preserve my quality of life in the process throughout my entire DCIS diagnosis and treatment.  

Tamoxifen reduces the risk of breast cancer recurrence. But, it can have systemic side effects for us. These side effects may have a negative impact on our quality of life. As with any cancer treatment, we must weigh the pros and cons and then work with our team to determine the best course of action for us.