What Is Megestrol Acetate?

Megestrol acetate is a medication derived from the natural hormone progesterone. It is used to treat a variety of cancers that can develop in the female reproductive organs, and is also given as an appetite stimulant for people with a syndrome called cachexia. Although the medication offers benefits to a number of patients, it can also cause side effects and should be used with caution in certain people.

The mechanism of action of megestrol acetate is that it binds to progesterone receptors in the body, and thus acts as a synthetic progesterone. Often people refer to the medication as simply megestrol because the acetate is an inactive stabilizer. The drug is commonly known by its brand name, Megace®. It can either be given as a pill or as a liquid medication, and in the United States it is only available by prescription.

Perhaps the most important use of megestrol is to treat cancers of the female reproductive organs. The medication has anti-neoplastic activities, meaning that it decreases the ability of malignant tumors to grow and spread. When used in this capacity, it is considered to be a chemotherapy agent. It is used to treat certain breast cancers and to treat endometrial cancer, a malignancy that develops in the lining of the uterine cavity. Often it is used in combination with other chemotherapy drugs in order to most effectively fight the cancer.

Another important use of megestrol is to increase patients’ appetites. It is commonly used to treat cachexia, a syndrome characterized by weight loss, muscle wasting, fatigue, and low appetite caused by severe underlying disease. Cancer patients often develop this syndrome, as do people with acquired immunodeficiency syndrome (AIDS).

Common side effects of megestrol acetate can include skin rashes, high blood pressure, diarrhea, vomiting, weight gain, hot flashes, and insomnia. Blood clots, diabetes mellitus, and heart failure are rarer, but more serious, side effects of the drug. Another dangerous side effect is that this medication can depress the activity of the adrenal gland, an important part of the body’s endocrine system. Low adrenal hormone production can result in low blood sugar, confusion, and a potentially fatal drop in blood pressure.

Although megestrol acetate is beneficial in treating a number of conditions, it is not safe to use in all patients. It should not be used during the first trimester of pregnancy, as it can result in birth defects. Women who are breastfeeding should also avoid the medication, because it could be harmful to the baby. Patients with a history of diabetes mellitus or blood clots should use caution before taking this medication, as they are prone to experiencing serious side effects.