PCOS Message Board - View Single Post - Any Femera/Letrozole users? I want info...

lonate · 11-14-2008, 02:48 PM

I have taken Femara two cycles..I took 5mg/day...I did not have any side effects at all. (when I was on clomid for 6 cycles I had HORRIBLE hot flashes). Here is an article that may be interesting to you:

In a prospective, double-blind, randomized study, 25 women were randomized to receive letrozole (2.5 mg for 5 days, starting on day 3) and 24 to clomiphene citrate (100 mg for 5 days, starting on day 3). The letrozole group had a much higher pregnancy rate (16.7% vs. 5.6%), said Dr. Biljan of McGill University, Montreal, an investigator in the study.

In addition, on the day of HCG administration, the letrozole patients had a thicker endometrium (8.6 mm vs. 6.9 mm), which may have been the result of a more favorable hormonal environment, Dr. Biljan suggested.

"In patients treated with letrozole there are a number of small follicles [that are] not large enough to ovulate but large enough to contribute to estrogen production, which probably corrects the hormonal environment and increases pregnancy rates," he said.

Another advantage of letrozole is that patients experience fewer side effects while on it. "Most patients on clomiphene citrate suffer from mood swings, vaginal dryness, and hot flushes, but none of these symptoms were present in our letrozole patients. The only side effect we noticed is tiredness," he said.

In addition, letrozole rarely stimulates more than one follicle to ovulate. "This is perhaps one of the most important elements in favor of letrozole. While with clomiphene there are an increased number of eggs produced--and therefore the risk of multiple pregnancy is increased--in the letrozole group there is usually only one mature follicle, rarely two, and therefore the risk of multiple pregnancy is practically zero," Dr. Biljan said.

Dr. Robert Casper, professor and head of reproductive sciences in the department of obstetrics and gynecology at the University of Toronto, said that letrozole's low risk of multiple pregnancy and positive effect on endometrial thickness mean that patients require virtually no monitoring.

"They don't need to have ultrasounds to measure their lining or their number of follicles, so even physicians with very little experience in infertility can feel comfortable prescribing this," he said.

An added bonus is that it may be possible to take letrozole as a one-time dose, according to the results of his latest study.

"It actually clears the body faster [when taken as a one-time dose], which improves the safety profile around ovulation and early embryogenesis and therefore may improve outcome," he said in an interview.

Dr. Casper's study looked at seven patients, three with polycystic ovary syndrome and four with unexplained infertility. These patients were given the single-dose regimen of letrozole (20 mg taken on day 3), and their results were compared with a historical cohort of 105 cycles of the standard dose (2.5 mg/day on days 3-7).

There were no significant differences between the groups regarding the day of HCG administration, endometrial thickness, number of follicles, or estradiol and LH levels.

"Besides the improved safety profile, taking one pill is so much more simple and convenient, and there is also the decreased cost of medication preparation," he said.

Dr. Casper has also done some preliminary work using letrozole in combination with follicle-stimulating hormone for in vitro fertilization.

"When we add it to FSH, we've found we can use half the dose of FSH and still get the same number of eggs. And in poor responders, we can get twice as many eggs when we add letrozole to FSH, compared with FSH alone. So it seems to have a lot of potential for different types of fertility treatment, including in vitro fertilization," Dr. Casper noted.

Letrozole is marketed in the United States by Novartis as Femara.