How It Works
Megestrol is a man-made
progestin similar to the hormone
progesterone. Experts do not completely understand how
megestrol works. But most believe that it interferes with receptors that help
breast cancer grow and spread.
Why It Is Used
Megestrol can be used to treat
metastatic or recurrent breast cancer after tamoxifen
treatment. It can also be used when tamoxifen is not effective.
Megestrol is used mainly to treat breast cancer. It is also sometimes
used to treat
endometrial cancer and
Megestrol can be used as
an appetite stimulant for people experiencing loss of appetite and weight loss
because of advanced cancer.
How Well It Works
Megestrol may be helpful for women with metastatic cancer who were already treated with another hormone therapy. But other medicines may work better than megestrol.
Megestrol may help
relieve bone pain, and it can improve appetite and weight gain.1
Side effects of megestrol
Megestrol may raise your risk for dangerous
blood clots (deep vein thrombosis). This risk is even
higher if you are a woman who smokes or if you have had blood clots in the past.
See Drug Reference for a full list of side
effects. (Drug Reference is not available in all systems.)
What To Think About
Megestrol should be used only under
the supervision of a
Megestrol can cause
birth defects. Do not use this medicine if you are pregnant or wish to become
If you have
diabetes, you may need to adjust your insulin dose
while you are being treated with megestrol. You will need regular appointments
with your doctor to monitor your insulin levels.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
Stebbing J, Ngan S (2010). Breast cancer (metastatic), search date June 2009. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
Primary Medical Reviewer
||Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer
||Douglas A. Stewart, MD - Medical Oncology
||August 11, 2011