| Active substance | Letrozole |
| US Brand | Femara |
| IN Brand | Fempro / Letronat |
| Manufacturing by | Cipla / Natco |
| Strength | 2.5 mg |
| Form release | blister 10 tablets |
| Shipping time | 7 – 18 days (Depending from the Country) |
| Availability & Order | through request form |
When the enzyme aromatase is inhibited by the letrozole medication, estrogen levels are suppressed in young women. This results in the brain and pituitary gland increasing the output of FSH (follicle stimulating hormone).
In women that have polycystic ovary syndrome or anovulation (a problem with ovulation) the increase in FSH hormone can result in development of a mature follicle in the ovary and ovulation of an egg. Doctors call this process “induction of ovulation”.
The anti-estrogen action of letrozole has been shown to be useful in pretreatment for termination of pregnancy, in combination with misoprostol. It can be used in place of mifepristone, which is expensive and unavailable in many countries.
Some studies have shown that letrozole can be used to promote spermatogenesis in male patients suffering from nonobstructive azoospermia.
Letrozole has also been shown to delay the fusing of the growth plates in mice. When used in combination with growth hormone, letrozole has been shown effective in one adolescent boy with a short stature.
Letrozole has also been used to treat endometriosis.
- The most common dose of Fempro is 2.5 mg per day on days five through nine of the menstrual cycle
- Sometimes it is given in higher doses of 5 mg or 7.5 mg per day
Report on Higher Incidence of Birth Defects
Many physicians will not prescribe letrozole because of concerns from a 2005 report from some Canadian fertility doctors suggesting a possible higher incidence of birth defects in pregnancies from using letrozole.
- This study was from a small group of pregnancies and the study has been severely criticized for having an improper design
- Letrozole is known to have a short half-life in the bloodstream and is given early in the menstrual cycle – several days before a fertilized embryo is present.
- It is believed that the drug has cleared from the system before the egg is fertilized. Therefore, it is puzzling as to how the drug could cause birth defects.
- The manufacturer of letrozole sent a warning to doctors saying there are reported birth defects in children born after mothers took Femara. This may have been due to liability concerns (lawyers and financial risks for a drug company) rather than real science.
- The manufacturer of the drug has apparently not filed for FDA approval to use it for infertility. However, physicians often use medications in an “off label” way. When the off label use is safe and effective it is perfectly legitimate.
