Aromatase Inhibitors: Femara and Arimidex
Among a new line of infertility treatment drugs aimed at balancing hormone levels such as estrogen and testosterone are aromatase inhibitors in the form of anastrozole (Arimidex) and letrozole (Femara). Originally used in the treatment of cancers, such as breast cancer and prostate cancer, these fertility drugs are now being used in individuals trying to conceive - and particularly in those experiencing unexplained infertility or who do not respond to clomiphene citrate (Clomid). However, the potential risks and side effects associated with this type of hormone therapy are not well understood, and some would even recommend refraining from its use.
What are Aromatase Inhibitors?
Aromatase is an enzyme that is required for the conversion of androgens or "male" hormones such as testosterone into estrogen. Excess levels of estrogen as well as progesterone deficiencies are believed to be related to the following health conditions in women:
- weight gain
- fibrocystic disease of the breast
- menstrual disturbances and certain types of PMS
- ovarian cysts
In men, high levels of estrogen have been linked to prostate cancer, testosterone imbalance, and impaired sperm count. Environmental factors such as chemicals containing xenoestrogens- which mimic natural estrogen - have been linked to estrogen dominance.
Testosterone is naturally converted into estrogen by aromatase. It has been found that as men age, whether due to genetic factors or environmental ones, too much testosterone is converted into estrogen. Aromatase inhibitors thus work by decreasing the amount of testosterone that is converted into estrogen, thus balancing hormone levels.
Aromatase Inhibitors and Female Fertility
Aromatase inhibitors like Femara may be used to stimulate ovulation in women. By suppressing estrogen production, aromatase inhibitors encourage the production of LH and FSH, hormones that trigger ovulation. Clinically, doctors have prescribed aromatase inhibitors to treat the following conditions in women:
- to promote healthy breast tissue
- to balance estrogen levels
- to treat uterine fibroids
Femara has been associated with higher rates of success as compared with the use of Chlomid in women trying to conceive. This aromatase inhibitor is believed to increase the chances of a womanï¿½s ovulation by 60% to 80%.
Many aromatase inhibitors are released from the body within 45 hours. This suggests that taking oral doses of aromatase inhibitors should pose little to no harm to the body or the developing embryo if a woman stops taking the drug immediately after getting pregnant. Continuing to take Femara while pregnant is indeed considered the cause of a low number of birth defects associated with the drug in the past.