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Becky · 03-23-2006, 09:03 AM

First, I will explain how aromatase inhibitors (Arimidex, Femara and Aromosin) work and how Tamoxifen works. Although all do cross the blood brain barrier, it is more important that Tamoxifen does and I will explain why (IMHO) below.

Aromatase inhibitors (Ais) work by preventing the conversion of androgens to estrogen by the catalyst aromatase. Androgens are made after menopause by the adrenal glands and adipose tissue (fat – this is why I stated to be at a normal or below normal body weight). It is NOT important that aromatase inhibitors cross the blood brain barrier (but they do) because they are effective because they prevent the production of estrogen. No estrogen, no binding to the estrogen receptor – no growth and reproduction of cancer cells.

Tamoxifen works (much like Herceptin’s mechanism) by binding to the estrogen receptor (whereas Herceptin binds to the Her2 receptor). Since tamoxifen is bound there, then estrogen cannot bind there and excite the cell to grow and reproduce. It is much more important that tamoxifen be able to cross the blood brain barrier because if there is a cancer cell in the brain, you need tamoxifen to get there and bind to those receptors. In the case of aromatase inhibitors – they just make sure there is no estrogen being made to be able to bind to the receptor. I hope I have made this part clear.

Please be aware that there are many studies showing that aromatase inhibitors work better than tamoxifen overall no matter what your Her2 status is (although you can only take an AI if you are postmenopausal) and that AI’s are better than tamoxifen especially if you are:

Her2 positive or progesterone negative (but naturally estrogen positive or else you wouldn’t need to take one).

As far as the amount of medication being the same, I am not 100% sure of the answer but I do know that there were many trials on how much Arimidex to give and they found that the dose we all get is optimum. They did the trial going up to 10X that dose and it was not beneficial at all and caused lots of side effects (I read this one and will look for it).

Hopefully I have helped out.

Warm regards

Becky

03-23-2006, 09:03 AM	#7
Becky Senior Member Join Date: Sep 2005 Location: Stockton, NJ Posts: 4,179	First, I will explain how aromatase inhibitors (Arimidex, Femara and Aromosin) work and how Tamoxifen works. Although all do cross the blood brain barrier, it is more important that Tamoxifen does and I will explain why (IMHO) below. Aromatase inhibitors (Ais) work by preventing the conversion of androgens to estrogen by the catalyst aromatase. Androgens are made after menopause by the adrenal glands and adipose tissue (fat – this is why I stated to be at a normal or below normal body weight). It is NOT important that aromatase inhibitors cross the blood brain barrier (but they do) because they are effective because they prevent the production of estrogen. No estrogen, no binding to the estrogen receptor – no growth and reproduction of cancer cells. Tamoxifen works (much like Herceptin’s mechanism) by binding to the estrogen receptor (whereas Herceptin binds to the Her2 receptor). Since tamoxifen is bound there, then estrogen cannot bind there and excite the cell to grow and reproduce. It is much more important that tamoxifen be able to cross the blood brain barrier because if there is a cancer cell in the brain, you need tamoxifen to get there and bind to those receptors. In the case of aromatase inhibitors – they just make sure there is no estrogen being made to be able to bind to the receptor. I hope I have made this part clear. Please be aware that there are many studies showing that aromatase inhibitors work better than tamoxifen overall no matter what your Her2 status is (although you can only take an AI if you are postmenopausal) and that AI’s are better than tamoxifen especially if you are: Her2 positive or progesterone negative (but naturally estrogen positive or else you wouldn’t need to take one). As far as the amount of medication being the same, I am not 100% sure of the answer but I do know that there were many trials on how much Arimidex to give and they found that the dose we all get is optimum. They did the trial going up to 10X that dose and it was not beneficial at all and caused lots of side effects (I read this one and will look for it). Hopefully I have helped out. Warm regards Becky Last edited by Becky; 03-23-2006 at 09:05 AM..