Side Effects switching from Tamoxifen to Anastrozole

Dstruthe

I have been on tamoxifen for 4 years and it is now time to switch to an AI. If you have switched from tamoxifen to an aromatase inhibitor (specifically anastrozole), what was your experience? Did you gain weight? Pain?

I've tolerated Tamoxifen pretty well, with the worst side effect being weight gain that will NOT come off.

Thanks for your thoughts!

myrob253

I was diagnosed in 2011, took tamoxifen for about a year and was then switched to anastrazole which I took up until February of this year. My worst side effect was the joint pain especially in the last year. I’ve been off of anastrazole for about eight months now and the pain has gotten worse since stopping.

Kaiyla

I am taking anastrazole, and since taking it, have an increased elevation of right leg groin pain ( upper thigh area) 5 out of 7 days per week. I hardly walk on the bad days....hmmm, wonder if it is a link?

a5hl3y5ibley

I take Arimidex (Anastrazole) daily (for two months now) and thankfully have had no side effects. Maybe I haven’t taken it long enough to chime in. Most of my side effects have come from its partner drug (Kisqali).

mssimone

Hi I have been on Tamoxifen for less than 3 weeks now and I too have been experiencing right leg groin pain in the upper thigh area. It fluctuates alot, some days are more painful than others, but it's been like weeks now so my Oncologist sent me for a CT Scan tomorrow. My cancer is in my left breast, but I just started having pain and some swelling in my right upper underarm too. So frustrating

manja

I am on Tamoxifen for about 3 months now. I am wondering why you have to switch to an aromatase inhibitor.

I know many women that were on Tamoxifen for 5-10 years without switching.🙅

Dstruthe

I think it depends on your age and menopause status. I was 50 when I was diagnosed but not yet in menopause. Once I started tamoxifen my periods stopped, but it still took 3+ years for my estrogen levels to come down enough to go on an AI. I think the AI is slightly better at preventing a reoccurrence. Tamoxifen carries with it the risk of blood clots and uterine cancer, although very small, so my oncologist wanted to switch me to an AI. But the downside of an AI is that it softens your bones. It is a balancing act either way.

Dstruthe

https://csn.cancer.org/discussion/comment/1701948#Comment_1701948

I think it depends on your age and menopause status. I was 50 when I was diagnosed but not yet in menopause. Once I started tamoxifen my periods stopped, but it still took 3+ years for my estrogen levels to come down enough to go on an AI. I think the AI is slightly better at preventing a reoccurrence. Tamoxifen carries with it the risk of blood clots and uterine cancer, although very small, so my oncologist wanted to switch me to an AI. But the downside of an AI is that it softens your bones. It is a balancing act either way.

dicon

I was on tamoxifan for 5 years and stopped and was told you have to stay on it 10 years. I did not and had a recurrence. AIs were not an option then.

Now, After all the usual treatments my Onc put me on arimidex. I did some reading and asked if, with my spine osteoporosis should I be on tamoxifen instead as studies shoe AIs are tough on bone density. ? She said just take the osteoporosis meds (Boniva)with it. Well, after 11 months I had so much bone pain and tight joints, hip weakness, I thought it was the arimidex. So I asked to switch back to tomoxifin. I took a week off arimidex then started tomoxifen. Im aleady feeling better off Arimidex although AIs stay in your system a long time. Years ago I only had hot flashes on tomoxifin as a side effect, at 75, Imcan handle that better than fractures and bone pain. Im staying on the boniva for a while.