Concerned about the side effects of anastrozole

Hi Celia,
That must be so confusing to get different opinions from different specialists. Perhaps I can clarify at least one apparent misunderstanding. Aromatase inhibitors (AIs) are a class of drugs that stop the production of estrogen in postmenopausal women. There are several kinds, for example:
Anastrozole (Arimidex)
Letrozole (Femara)
Exemestane (Aromasin)

It sounds like the first oncologist suggests anastrozole (brand name Arimidex) and the second prescribed exemestane (brand name Aromasin). Studies have found that they are equally effective, but they have different side effects. Every person reacts differently, so the choice is usually made according to which side effects you experience and which you can tolerate.

Tamoxifen is the oldest and most-prescribed selective estrogen receptor modulator (SERM). While an aromatase inhibitor is the first hormonal therapy medicine choice for postmenopausal women, tamoxifen is the first choice for premenopausal women and is still a good choice for postmenopausal women who can't take an aromatase inhibitor.

A number of studies have compared aromatase inhibitors with tamoxifen to see which type of medicine was more effective in treating early-stage, hormone-receptor-positive breast cancer in postmenopausal women.

I copied selected information above from the website BreastCancer.org from these 2 articles:
- https://www.breastcancer.org/treatment/hormonal/aromatase_inhibitors
- https://www.breastcancer.org/treatment/hormonal/serms/tamoxifen

I hope this helps to give you more information to discuss with your oncologist. I also look forward to hearing the experiences of others who may have had to choose between an AI and Tamoxifen.

@veras
I'm surprised that your oncologist didn't treat the bone thinning with biphosphonates when signs of osteopenia first were evidenced.

@brianphilip
Tamoxifen is prescribed to pre-menopausal women and has many side effects (some especially serious like blood clots, stroke, endometrial cancer, etc.). AIs are prescribed to post-menopausal women.

I am post menopausal and am on Tamoxifen. I was on anastrozole over 2 years and it weakened my bones to the point of osteoporosis. My Oncologist switched me over to the Tamaxifen.

also be sure to ask about possible interactions with other drugs that you might be taking. I am beginning to think that some of my side effects such as joint pain are from an interaction between atorvastatin (Lipitor) and the anastrazole… Sometimes things happen that are not within the doctor's usual scope of knowledge.

You could ask your Oncologist about Tamoxyfen which has been on the market for many years and is very well tolerated and has very little side effects to none compared to Anastrazole with terrible side effects. One sometimes wonders if some Doctors have a personal interest in this prescription!
Ask for a second opinion without mentioning Anastrazole.

@kathyomaha55 @cemd03
As @cemd03 noted, exercise helps with the fatigue (try something easy on arthritic joints like walking briskly on a treadmill at the gym). As you likely, know, one of the biggest side effects of radiation is fatigue and you likely will battle that for at least a year. My favorite product for dry eyes is Systane Gel Drops, by the way; and, for hot flashes, a Chinese herbal called Zhi Bai Di Huang Wan which I get from a doctor of Chinese medicine.

As to the anastrozole, arthralgia (and fatigue) is a common side effect, and, yes, it's difficult to discern what is arthritis pain and what is the arthralgia pain from the anastrozole. Again, try something easy on the joints like walking briskly on a treadmill at the gym. It helps with both conditions.

Genetics play a role in how we metabolize drugs and experience their side effects. About a third of us taking any kind of AI experience muscle and bone aches/pains with them. About 25% either don't start taking a prescribed AI or stop taking it early because of side effects. I've seen stats which suggest that maybe the majority of us don't continue for the length of time prescribed. The fact remains: those with hormone positive BC who do not take an AI are more likely to experience a recurrence... and that should serve as an incentive to try taking one.

If you are struggling with anastrozole, ask your oncologist to switch you to femara or aromasin to see if your particular body can accommodate one of them with fewer issues. AIs work to block cell receptors like estrogen and progesterone in breast cancers that are hormone receptor positive in post-menopausal women. Another choice is to take half a pill per day, or, none at all. Just be sure that you are making an informed choice, however, and read up on all the studies.

And lastly, be easy on yourself. Take that nap when needed... no shame there. No one ever said that cancer recovery was going to be a snap. A good diet also is important, as is achieving and maintaining a healthy weight, getting regular screening mammograms, and bone density tests. We're strong... and we can get this recovery business right!