Has anyone here experienced an estrogen rebound when using femara? I've been told that the rebound on this is worse than with arimidex. It's been suggested that the best way to counter it is to slowly taper down to zero as you end your cycle, then begin post cycle therapy (pct) with either clomid or Nolva. Does anyone have any input or experience on this? Thanks.
Estrogen Rebound
- Thread starter DIEZEL666
- Start date
TxLonghorn
Community Veteran
DADAWG said:
Woof! (that's dawg for 'ditto')
Annonamous1
New member
I would run it all the way through post cycle therapy (pct) tapering down at the end.
Guys, run the Femara/Arimidex/Aromasin throughout your Anabolic Androgenic Steroids (AAS) cycle (assuming your are using an aromatizing AAS). Then, when you begin your Recovery cycle, you will be switching to Nolvadex. It takes time to get rid of the free estrogen--the liver and kidneys are working hard to do this. After all the hard work, you do not want all of that excess estrogen stimulating alpha-receptors.
StoneColdNTO
Administrator
DIEZEL666 said:
I would sure like to see a study on humans that shows Nolva decrease Femara's effectiveness by 40%, until then I say that's just another internet rumor.
hhajdo
Community Veteran
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.
http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=10499602&dopt=Abstract
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.
http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=10499602&dopt=Abstract
StoneColdNTO
Administrator
hhajdo said:
Thanks......but that truely does suck. I've already got my Femara for my next cycle and was planning on running a low dosage of Nolva as well.....hummm ??....Decisions, decisions
StoneColdNTO
Administrator
SWALE said:
Do you doubt it's correct ?
hhajdo
Community Veteran
SWALE said:
They weren't sure about the mechanism...
http://clincancerres.aacrjournals.org/cgi/content/full/5/9/2338
"The mechanism is likely to be a consequence of an induction of letrozole-metabolizing enzymes by tamoxifen but was not further addressed in this study".
Also: "The reduction varied between patients, ranging from no reduction in one patient to a reduction of almost 70%. "
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StoneColdNTO
Administrator
hhajdo...............
this is from the "discussion" from that study, does the bolded part mean what I think it means.........that althogh letrozole levels were reduced, what was left still had the same effect even though nolva was added ?? Therefore it should not matter, as it will still stop aromatization for us.
Hormone levels (E1, E2, and E1S) dropped significantly as compared to baseline during letrozole monotherapy. The addition of tamoxifen did not cause any significant change to the diminished hormone levels. This suggests that although letrozole levels were reduced by the addition of tamoxifen, the effect of letrozole on hormone levels remains largely unaltered. Any minor alterations are unlikely to be detected because many estrogen levels were below the limit of detection of the assay. Levels of SHBG, LH, and FSH did not change significantly from baseline on the addition of letrozole, as has been reported previously (2) . The apparent decreases in LH and FSH levels and increases in SHBG levels on the introduction of tamoxifen are also consistent with previous reports on tamoxifen alone (25) . Thus, the pharmacodynamic changes with the two drugs appear to be independent of one another and would not be expected to compromise their activity.
this is from the "discussion" from that study, does the bolded part mean what I think it means.........that althogh letrozole levels were reduced, what was left still had the same effect even though nolva was added ?? Therefore it should not matter, as it will still stop aromatization for us.
Hormone levels (E1, E2, and E1S) dropped significantly as compared to baseline during letrozole monotherapy. The addition of tamoxifen did not cause any significant change to the diminished hormone levels. This suggests that although letrozole levels were reduced by the addition of tamoxifen, the effect of letrozole on hormone levels remains largely unaltered. Any minor alterations are unlikely to be detected because many estrogen levels were below the limit of detection of the assay. Levels of SHBG, LH, and FSH did not change significantly from baseline on the addition of letrozole, as has been reported previously (2) . The apparent decreases in LH and FSH levels and increases in SHBG levels on the introduction of tamoxifen are also consistent with previous reports on tamoxifen alone (25) . Thus, the pharmacodynamic changes with the two drugs appear to be independent of one another and would not be expected to compromise their activity.
hhajdo
Community Veteran
The dose used (2.5 mg ED) was sufficient to suppress their estradiol to undetectable values (the subjects were postmenopausal women and letro is probably the most potent aromatase inhibitor)... so:
"Any minor alterations are unlikely to be detected because many estrogen levels were below the limit of detection of the assay"...
If the subjects were men & if the assay was more sensitive, they would have probably noticed a difference...
"Any minor alterations are unlikely to be detected because many estrogen levels were below the limit of detection of the assay"...
If the subjects were men & if the assay was more sensitive, they would have probably noticed a difference...
StoneColdNTO
Administrator
Thanks hhajdo !!
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