Megestrol (Megace®, Megace-ES®)
Last Modified: August 22, 2011
Classification: Progestational Agent
Megestrol is a man-made version of progesterone, which is a type of female hormone. Megestrol works by interfering with estrogen production. While estrogen may not actually cause breast cancer, it appears to be a necessary component in the growth of estrogen receptor-positive breast cancers. With estrogen blocked, the cancer cells that normally feed off estrogen may not be able to survive.
How to Take Megestrol
Megestrol comes as a tablet, a suspension (liquid), and a concentrated suspension (Megace ES) to take by mouth. The dosage and schedule depend on which formulation you are taking and what it is being used to treat. Take megestrol at around the same time(s) every day.
Possible Side Effects of Megestrol
There are a number of things you can do to manage the side effects of Megestrol. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:
Swelling of the hands, feet, and ankles due to fluid retention is a common, but not harmful, side effect. Elevating the feet may help to lessen swelling in the feet and ankles. Avoid restrictive or tight clothing that may make it harder for the fluid to drain from the hands, feet and ankles.
Weight gain is a common side effect of megestrol acetate, which is why it sometimes used to treat cachexia (muscle and weight loss or wasting and anorexia associated with cancer). This may be managed through dietary changes and exercise.
In general, bleeding associated with megestrol acetate occurs when the drug is stopped. Some vaginal bleeding may be due to irregular periods as a result of chemotherapy. Vaginal bleeding may also be a part of the natural transition into menopause. However, women who are already post-menopausal at the time they start megestrol acetate should report any vaginal bleeding to their oncologist, primary physician, or gynecologist.
Blood clots are a rare side effect that can occur anywhere in the body. They occur most frequently in the calves and can then travel to the lungs. People at risk for developing blood clots include those with a family history of blood clots, smokers, those who have an inactive lifestyle, older women, and those with other medical problems.
Signs of a blood clot in the leg may include any of the following: leg pain, warmth, swelling of one leg more than the other. Signs of a blood clot in the lung could include: fever, shortness of breath that comes on very quickly, racing heart, chest pain (especially pain that worsens when you take a deep breath).
If you have any of these signs or symptoms of blood clots, you will need to be seen immediately so that you can be treated. Blood thinners can be given. Call your doctor or nurse.