Megestrol

(me-JES-trole)

Trade name: Megace^®
Other name: Megestrol Acetate

Drug type:  Megestrol is a hormone therapy.  This medication is classified as a "progesterone." (For more detail, see "How this drug works" section below).

What This Drug Is Used For:

• Treatment of breast, and endometrial cancers.
• Use as a supportive medication to treat severe loss of appetite (anorexia), muscle wasting (cachexia) and significant weight loss (> 10% of baseline body weight) associated with cancer and/or AIDS.

Note:  If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.

How This Drug Is Given:

• Megesterol is given by mouth in tablet form, or as a liquid suspension.
• The amount of megesterol that you will receive depends on many factors, including your height and weight, your general health or other health problems, and the type of cancer or condition you have.  Your doctor will determine your dose and schedule. 

Side Effects:

Important things to remember about the side effects of megestrol:

• Most people do not experience all of the side effects listed.
• Side effects are often predictable in terms of their onset and duration.
• Side effects are almost always reversible and will go away after treatment is complete.
• There are many options to help minimize or prevent side effects.
• There is no relationship between the presence or severity of side effects and the effectiveness of the medication.

The following side effects are common (occurring in greater than 30%) for patients taking megestrol:

Note: there are no common side effects of megesterol.

These are less common side effects (occurring in 10-29%) for patients receiving megestrol: 

• Weight gain
• Edema (swelling, usually in the feet or hands)
• Breakthrough menstrual bleeding, spotting

Not all side effects are listed above, some that are rare (occurring in less than 10% of patients) are not listed here.  However, you should always inform your health care provider if you experience any unusual symptoms.

When to contact your doctor or health care provider:

Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:

• Difficulty breathing
• Chest pain
• Sudden severe headache

The following symptoms require medical attention, but are not an emergency.  Contact your health care provider within 24 hours of noticing any of the following:

• Swelling, redness and pain in one leg or arm and not the other
• Swelling of the face, lips or mouth
• Abdominal pain
• Vaginal itching, irritation or discharge

Always inform your health care provider if you experience any unusual symptoms.

Precautions:

• Before starting megestrol treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.). 
• Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment. Pregnancy category X (megestrol may cause fetal harm when given to a pregnant woman.  This drug must not be given to a pregnant woman or a woman who intends to become pregnant.  If a woman becomes pregnant while taking megestrol, the medication must be stopped immediately and the woman given appropriate counseling).
• For both men and women: Use contraceptives, and do not conceive a child (get pregnant) while taking megestrol. Barrier methods of contraception, such as condoms, are recommended.
• Do not breast feed while taking this medication.

Self-Care Tips:

• Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
• Use caution when driving or engaging in tasks that require alertness until response to the drug is known.
• Avoid sun exposure.  Wear SPF 15 (or higher) sunblock and protective clothing.
• Get plenty of rest. 
• Maintain good nutrition.
• If you experience symptoms or side effects, be sure to discuss them with your health care team.  They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and Testing:

You will be checked regularly by your doctor while you are taking megestrol, to monitor side effects and check your response to therapy.  Periodic blood work to monitor your complete blood count (CBC) as well as the function of other organs (such as your kidneys and liver) will also be ordered by your doctor.   

How This Drug Works:

Megestrol is a type of hormone therapy. Hormones are chemical substances that are produced by glands in the body, which enter the bloodstream and cause effects in other tissues.  (For example, the hormone testosterone made in the testicles is responsible for male characteristics such as deepening voice and increased body hair). The use of hormone therapy to treat cancer is based on the observation that receptors for specific hormones that are needed for cell growth are on the surface of some tumor cells.  Hormone therapies work by; stopping the production of a certain hormone, blocking hormone receptors, or substituting chemically similar agents for the active hormone, which cannot be used by the tumor cell.  The different types of hormone therapies are categorized by their function and/or the type of hormone that is affected.

Megestrol is a progestin (a man-made form of the hormone progesterone).  It has properties that interfere with the normal estrogen cycle.  This interferes with the stimulation of cell growth in estrogen dependent tumor cells.  There is also thought to be some direct effect on the lining of the uterine wall (endometrium).

A side effect of megestrol has been weight gain.  The exact mechanism of this effect is unclear, however the effects lead to an increase in body fat.  Taking advantage of this side effect, megestrol has been studied and used to treat severe appetite loss (anorexia), muscle wasting (cachexia) and weight loss associated with cancer and AIDS.

Note:  We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice.

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