Please Scroll Down to See Forums Below 
tamox can decrease plasma levels of letrozole ...
Drug and hormone interactions of aromatase inhibitors.
Dowsett M.
Academic Department of Biochemistry, The Royal Marsden NHS Trust, London, UK.
The clinical development of aromatase inhibitors has been largely confined to postmenopausal breast cancer patients and strongly guided by pharmacological data. Comparative oestrogen suppression has been helpful in circumstances in which at least one of the comparitors has caused substantially non-maximal aromatase inhibition. However, the triazole inhibitors, letrozole and anastrozole, and the steroidal inhibitor, exemestane, all cause >95% inhibition. Comparisons between these drugs therefore require more sensitive approaches such as the direct measurement of enzyme activity by isotopic means. None of these three agents has significant effects on other endocrine pathways at its clinically applied doses. Pharmacokinetic analyses of the combination of tamoxifen and letrozole have revealed that these drugs interact, resulting in letrozole concentrations approximately 35-40% lower than when letrozole is used alone.
Online!
Couple questions:
If one is running femara, wouldn't you probably not need nolvadex anyways as estrogen would be very low?
In light of this study, for those that are gyno prone, would armidex/nolva be a better option rather then femara/nolvadex?
Even if nolvadex reduces concentrations of femara by 35-40%, wouldn't it not matter anyways, the nolvadex will still occupy the ER and prevent gyno from forming and the letro will still be inhibiting a significant amount of estrogen? So there should still be no worries right?
One more:
What is the half life of nolva, just wondering how long it will have an effect on letrozole concentrations?
thanks for all your help
Fat_sumo
Drug and hormone interactions of aromatase inhibitors.
Dowsett M.
Academic Department of Biochemistry, The Royal Marsden NHS Trust, London, UK.
The clinical development of aromatase inhibitors has been largely confined to postmenopausal breast cancer patients and strongly guided by pharmacological data. Comparative oestrogen suppression has been helpful in circumstances in which at least one of the comparitors has caused substantially non-maximal aromatase inhibition. However, the triazole inhibitors, letrozole and anastrozole, and the steroidal inhibitor, exemestane, all cause >95% inhibition. Comparisons between these drugs therefore require more sensitive approaches such as the direct measurement of enzyme activity by isotopic means. None of these three agents has significant effects on other endocrine pathways at its clinically applied doses. Pharmacokinetic analyses of the combination of tamoxifen and letrozole have revealed that these drugs interact, resulting in letrozole concentrations approximately 35-40% lower than when letrozole is used alone.
Online!
Couple questions:
If one is running femara, wouldn't you probably not need nolvadex anyways as estrogen would be very low?
In light of this study, for those that are gyno prone, would armidex/nolva be a better option rather then femara/nolvadex?
Even if nolvadex reduces concentrations of femara by 35-40%, wouldn't it not matter anyways, the nolvadex will still occupy the ER and prevent gyno from forming and the letro will still be inhibiting a significant amount of estrogen? So there should still be no worries right?
One more:
What is the half life of nolva, just wondering how long it will have an effect on letrozole concentrations?
thanks for all your help
Fat_sumo
