Can anyone speak to the pros/cons of arimidex vs. tamoxifen?

I was on tamoxifen for seven months but found the side effects difficult. Tamoxifen caused severe leg cramping, menopausal symptoms (I am post-menopausal), abdominal discomfort, and depression. I began to fear endometrial thickening and leg thrombosis. My oncologist switched me to Arimidex/anastrazole, which I have been taking since March with very slight SE's. With anastrazole (Accord brand) I get some occasional slight nighttime foot cramping. Both hormone blockers seem to cause hot flashes and increase insomnia. I experience no muscular aches and pains from the anastrazole. I take the pill in the morning with breakfast, followed by a walk, and that followed three days a week by weight training and yoga practice at the gym. I am hoping a good plant-based diet, exercise, and normal BMI, in addition to this little pill, keep me healthy and breast cancer recurrence free. No guarantees with any of these pills.

@abartels, what were your negative side effects to Tamoxifen? I've been on it for 5 1/2 months and I have also had some negative effects.

Provoked in early menopause, I had to have a uterine ablation. I run hot anyways but I also had severe hot flashes. I’m not a good sleeper but sleep seem to be harder. I ended up with a blood clot but I also have factor five. On the positive side I had check up last week and I am 14 years clear of cancer.

@vivi1 thank you for your reply. I'm having all kinds of different reactions to Tamoxifen and i can hardly wait to be able to stop it in January! I started out with Arimidex and simply could not tolerate that. Then some of the other drugs which were no better. Tamoxifen has had fewer side effects so I'll continue taking it until January. I hope all goes well with you!

My experience seems similar. I took aromatase inhibitor for a few months until the joint pain became so extreme I had difficulty walking. Dr switched me to tamoxifen; joint paint less but, esp at night, the pain radiated from my leg and hip joints, so I ended up taking Tylenol every night. I am now on a 2 week hiatus from all meds and the bone/joint pain is gone.

@abartels, what were your negative side effects to Tamoxifen? I've been on it for 5 1/2 months and I have also had some negative effects.

In mid-2000, I was diagnosed with an estrogen-positive breast cancer. After a lumpectomy and chemotherapy (my oncologist recommended because I was "young"—only 45 and he thought it would be in my best interest), I started taking Tamoxifen January 2001 while undergoing 6.5 weeks of radiation. About 10 weeks after starting Tamoxifen, it became obvious that the Tamoxifen was doing its job—binding to the estrogen in my system and putting me into a chemically induced menopause. I was put on 25mg, regular-release Effexor (venlafaxine) to control "hot flashes."

In late March 2004, I woke up on a Sunday thinking I had a "charlie horse" in my right calf. Nothing eased it and by Wednesday noon, I was at my regular doctor's for muscle relaxers. He knew I was on Tamoxifen and even though my leg was NOT red, NOT hot, NOT swollen, he sent me to the local hospital for a sonogram. Within minutes the sonogram confirmed that I had blood clot in my leg and I was whisked to the ER and given several abdominal shots of Lovenox (a blood-thinner) and admitted. I spent 8.5 days in the hospital, getting Lovenox shots twice a day as well as oral warfarin (another blood thinner). I was on warfarin for a year and had blood taken weekly to monitor and adjust the dose.

While there, they discovered that I had anemia—I had been having HEAVY periods for several months with little, or no pause between. I had a vaginal exam and some uterine biopsies taken. I had developed uterine cancer and needed a hysterectomy. Fortunately, all cancer was contained within the uterus.

BOTH the leg blood clot and uterine cancer were ATTRIBUTED to my Tamoxifen use. As soon as I was admitted to the hospital for the DVT, my oncologist took me off Tamoxifen.

After the hysterectomy, I was put on Aromasin (hey, I was now post-menopausal). I stayed on that for another 5 years until my oncologist said no further benefit would come from taking it any longer. (When I first went on Tamoxifen, five years was the suggested amount of time to be on it; later studies suggested 7–10 years for hormone inhibitors. I did not experience ANY joint/muscle aches/pains with either Tamoxifen, or Aromasin, so I admit to being reluctant to discontinue taking Aromasin when my oncologist said I didn't need it any more.)

The ONLY issue I had with Aromasin was that from the VERY FIRST dose, I would "urp, urp, urp" all night long after going to bed—no acid reflux, or burning in the throat, no upset tum, just HAD to release a burp. Careful reading of the teeny print on the multi-page drug info sheet that came with the Aromasin did show “dyspepsia” as a possible side effect. That side effect went away about three months after discontinuing Aromasin.

My experience seems similar. I took aromatase inhibitor for a few months until the joint pain became so extreme I had difficulty walking. Dr switched me to tamoxifen; joint paint less but, esp at night, the pain radiated from my leg and hip joints, so I ended up taking Tylenol every night. I am now on a 2 week hiatus from all meds and the bone/joint pain is gone.