Off Label Use
Femara (letrozole), a drug manufactured for the purpose of treating and preventing hormone-responsive breast cancer, has lots of fans for its off label use as a fertility drug. But Novartis has issued a warning to the effect that physicians shouldn't be prescribing the drug for purposes other than one for which it is intended. The company has a right to protect itself against liability, but where does that leave women who have had no success with other fertility drugs that induce ovulation, such as Clomid (clomiphene citrate)?
Does the Job
An early study of letrozole as a fertility treatment concentrated on 12 women who had been found to have an insufficient response to Clomid. Nine out of the 12 women ovulated and 3 of these nine conceived. The same researchers furthered their study of the drug by comparing the effects of the two drugs in a group of 19 women. Ten women were dosed with Clomid and nine took the letrozole. In this study, the scientists were unable to spot any difference in the rates of ovulation, the number of eggs produced, or the thickness of the uterine lining on treatment with either drug. Later studies did show that Clomid tends to thin the uterine lining, while Femara does not. Femara has also shown an association with a lower rate of miscarriage.
To date, the optimal dose for Femara remains undetermined. Tests have been performed using doses of 2.5 mg, 5 mg, and 7.5 mg. There is no conclusive result favoring one dose over another, however, the treatment duration is five days.
Pregnancy rates for both drugs remain similar, with gonadotropins still the winner. Older women have lower rates of conception than younger women.
Because the drug is metabolized so well, and the treatment is of a short duration, side effects are very minimal when Femara is used for infertility, though the same cannot be said for its long-term use as a breast cancer drug.
In general, Femara treatment protocol goes as follows:
Call the doctor on Day 1 of your period/cycle
Come in on Day 2 or 3 to have an ultrasound and blood work
Take a 2.5 mg. tablet of Femara on Days 5, 6, 7, 8, and 9
Begin taking morning urine tests on Day 10 or 11
Once the color change takes place, you can discontinue testing
Have intercourse or intrauterine insemination (IUI) on the day you see the color change and the day after
Call the office when you notice the color change and schedule an appointment for one week later to have a blood test to confirm that ovulation has occurred
The protocol is adapted when the drug is used in combination with injectable medications such as Human Chorionic Gonadotropin (hCG) which can up your chances of ovulation.