The Food and Drug Administration (FDA) has sanctioned the use of various prescription drugs, including Femara, to treat specific conditions. However, Femara is sometimes employed in an off-label capacity to address different conditions. Off-label use refers to the practice of utilizing a drug approved for one condition to treat another. A typical off-label use of Femara is treating female* infertility, particularly when ovulation issues cause it. The most prevalent ovulation problem leading to infertility is polycystic ovary syndrome (PCOS)†. Still, Femara is also occasionally used to treat unexplained infertility.
In all these situations, Femara treats infertility by inducing ovulation. To do this, one would take Femara for several days following the onset of their menstrual period, which temporarily reduces estrogen levels. This prompts the pituitary gland to release hormones known as follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones aid in the maturation and release of an egg from the ovary, thus triggering ovulation. This application of Femara is known as ovulation induction.
If you are already ovulating before taking Femara, the drug may stimulate more eggs to mature and release from your ovaries, a condition known as controlled ovarian hyperstimulation or superovulation. For more information on infertility and its causes, we have a comprehensive list of fertility articles.
Using Femara can increase your chances of conceiving if you’re trying to get pregnant through sexual intercourse or intrauterine insemination (IUI). However, the success rates of using Femara for conception or pregnancy maintenance depend on various factors such as the cause of infertility, your age, and whether Femara is used in conjunction with other fertility treatments. Femara is more likely to support a successful pregnancy if your body isn’t already ovulating.
To assess Femara’s effectiveness in clinical studies, refer to the drug’s prescribing information. If you have any queries or concerns about using Femara for infertility, consult with your doctor. International guidelines endorse letrozole, Femara’s active drug, as an efficient treatment for infertility.
The standard dosage of Femara to induce ovulation is 2.5 milligrams (mg) orally once daily for 5 days. Your doctor may instruct you to start taking the drug either on the 3rd or 5th day of your menstrual cycle. If you’re not menstruating when starting Femara, your doctor will advise when to start taking the drug.
Occasionally, your doctor may suggest a higher dosage of Femara, such as 5 mg or 7.5 mg daily for 5 days. The optimal dose of Femara for fertility treatment is yet to be determined. More research is needed to understand whether higher doses of Femara are more effective than lower ones. Always adhere to your doctor’s prescribed dosage of Femara.
When using Femara for infertility, some common mild and severe side effects may include dizziness, fatigue, hot flashes, breast tenderness, mood swings, night sweats, nausea, vomiting, and spotting (light vaginal bleeding between periods). Other less common but serious side effects are ovarian cysts and rarely, ovarian hyperstimulation syndrome (OHSS), which happens when more eggs than usual develop in your ovaries.
Femara should be taken orally once daily for five days following the onset of your menstrual cycle. Your doctor may recommend taking Femara on either cycle days 3 to 7 or cycle days 5 to 9. Ovulation usually occurs between 5 and 10 days after your last Femara tablet. Your doctor will generally recommend using an ovulation predictor test to help you determine when you’re about to ovulate. They will also advise when to start having sex if you’re trying to conceive naturally or when to go to the clinic for artificial insemination if you’re using IUI.
Femara can be taken at any time of the day, but it’s advisable to take it at approximately the same time on each of the 5 days you’re taking the drug. Most doctors won’t prescribe Femara for more than six treatment cycles as if you haven’t conceived after six cycles, it’s likely that this drug won’t work for you. If you haven’t conceived after six treatment cycles with Femara, discuss other infertility treatment options with your doctor.
Femara contains the active drug letrozole, while Clomid contains the active drug clomiphene. Clomid has been discontinued, but generic versions of clomiphene are still available. Both Femara and clomiphene are used to induce ovulation in females* who have trouble getting pregnant due to ovulation problems or unexplained infertility. Femara is used off-label for this purpose, while clomiphene is FDA-approved for treating infertility in females.
Both Femara and clomiphene work in slightly different ways in your body to induce ovulation. However, their effectiveness may depend on the cause of your infertility. Studies comparing the two drugs have found slightly differing results. A study in 2023 found Femara to be more effective than clomiphene in treating infertility in people with PCOS. A 2019 review of studies also found Femara to be more effective than clomiphene in treating infertility in females* with PCOS, while another 2019 review found Femara and clomiphene to be similarly effective in treating unexplained infertility.
There are many other drugs available to treat infertility, such as choriogonadotropin alfa (Ovidrel), which induces ovulation like Femara does, and progesterone (Prometrium), which induces menstruation. There are also other drugs used to treat infertility that perform different functions in your body. For more information on infertility treatment options, consult with your doctor.
*Sex and gender exist on spectrums. The use of the term “female” in this article refers to sex assigned at birth.
†PCOS is a condition that can cause hormone problems, irregular or skipped periods, and cysts on your ovaries. People with PCOS often don’t ovulate as usual, making it difficult for them to get pregnant.