Megestrol acetate is a progestin hormonal therapy. Progestins are human-made medicines that act like the natural hormone progesterone.

Megestrol acetate is the only FDA approved medicine in this class that is used to treat metastatic breast cancer or its symptoms. In addition to treating the cancer, megestrol acetate can be used to help grow your appetite.

How megestrol acetate works

This medicine is a human-made form of the hormone progesterone. It works to counteract some of the negative effects of estrogen, a hormone that helps hormone receptor-positive breast cancers grow.

Who gets megestrol acetate

Megestrol acetate is given to women with metastatic breast cancer that continued to grow despite treatment with other hormonal therapies.

How megestrol acetate is given

Megestrol acetate is given as a pill or as liquid, usually once per day, but it may also be given in smaller doses to be taken at regular times during the day.

Side effects and things to remember

Possible side effects are:

Megestrol acetate increases the risk of blood clots. Call your doctor right away if you have sudden swelling in your leg, or shortness of breath and chest pain.



Reviewed and updated: August 31, 2015

Reviewed by: Jennifer Winn MD, MS


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