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How do you take letrozole for fertility?

Medically reviewed by Sally Chao, MD. Last updated on July 22, 2024.

Official answer

by drugclasses.com

Letrozole is a prescription medicine that may be used off-label to treat female infertility by inducing ovulation. Off-label use is when a provider prescribes a medication that has been studied and found to be safe and effective, but it is used for a different purpose than its approved use.

Letrozole is from a class of medications called aromatase inhibitors. It is approved by the U.S. Food and Drug Administration (FDA) for the treatment of certain types of breast cancer.

Letrozole Dosage for Infertility

The recommended starting dose of letrozole to induce ovulation is 2.5 mg once a day for 5 days, beginning between days 2 and 5 of menstrual bleeding. The medicine can be taken at any time during the day, but it should be taken at the same time each day. Food does not interfere with the medicine, so it can be taken before or after eating.

You are then monitored by various methods to determine if and when you are ovulating. Once ovulation occurs, your egg may be fertilized through timed sexual intercourse, intrauterine insemination or in vitro fertilization.

If pregnancy does not occur with the first cycle, the process may be repeated for more cycles and the letrozole dose may be increased by 2.5 mg increments up to 7.5 mg. How many cycles to try is a decision between you, your partner and your doctor.

Side effects

Because letrozole is used off-label in this situation, it is difficult to determine how common side effects are for this specific regimen. When letrozole is given to treat breast cancer (which may be for as long as five years), common side effects include:

  • Hot flashes
  • Muscle aches
  • Flushing
  • Headache
  • Dizziness
  • Bone pain
References
  1. American Society for Reproductive Medicine (ASRM). Medicines for Inducing Ovulation. 2016. Available at: https://www.reproductivefacts.org/news-and-publications/patient-fact-sheets-and-booklets/documents/fact-sheets-and-info-booklets/medications-for-inducing-ovulation-booklet/. [Accessed July 19, 2021].
  2. 2. Williams T, Mortada R, Porter S. Diagnosis and Treatment of Polycystic Ovary Syndrome.Am Fam Physician. 2016;94(2):106-113. https://pubmed.ncbi.nlm.nih.gov/27419327/.
  3. U.S. Food and Drug Administration (FDA). Femara. April 2018. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/020726s035lbl.pdf. [Accessed July 15, 2021].
  4. U.S. Food and Drug Administration (FDA). Understanding Unapproved Use of Approved Drug "Off Label." Available at: https://www.fda.gov/patients/learn-about-expanded-access-and-other-treatment-options/understanding-unapproved-use-approved-drugs-label. [Accessed July 19, 2021].

Read next

How long do letrozole side effects last?

Most side effects of letrozole are mild and temporary, lasting only a few days or weeks until your body gets used to taking the medication. Some other side effects of letrozole take a few months to develop and tend to persist long term until you stop taking letrozole. The half-life of letrozole is 2 days, so once you stop taking letrozole, you might continue to experience side effects for about a week to 10 days after your last dose. Continue reading

What happens when you stop taking letrozole?

When you stop taking letrozole, side effects such as swelling, cough, hot flashes, and nausea, should improve within a week or 10 days. Some, such as high cholesterol, bone loss, and hair thinning may take many months to resolve. As long as you have taken it for at least 5 years, then letrozole should continue to reduce the risk of breast cancer coming back for many years after you stop taking it. Letrozole is usually taken for 5 years, but may be recommended for up to 10 years depending on individual circumstances. Continue reading

When is the best time of day to take letrozole?

You can take letrozole (Femara) in the morning or evening, but you should take it at about the same time each day. Taking it at the same time each day will help you to remember your dose. Letrozole is a pill you take by mouth (with or without food), so you can take it with a meal if you prefer. If you miss a dose, do not double your dose the next day. Continue reading

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