How does this medication work? What will it do for me?
Megestrol belongs to a group of medications known as progestogens. Megestrol is used to treat prostate cancer because testosterone is needed by prostate cancer cells for growth. It prevents the release of a hormone required for production of testosterone in the testicles.
Megestrol also slows the growth of breast and endometrium (lining of the uterus) cancer cells by interfering with other hormones and proteins that are required for growth of the cancer cells. It is also used to treat appetite loss and severe weight or muscle loss in people with cancer or acquired immunodeficiency syndrome (AIDS). It helps these conditions by promoting the production of certain proteins that increase appetite and weight gain.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Each light blue, round, flat-faced, beveled-edged, scored tablet, engraved "40" on one side, contains megestrol 40 mg. Nonmedicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose, magnesium stearate, microcrystalline cellulose, and Brilliant Blue FCF Lake 12% (dye).
Each white, oval, biconvex, scored tablet engraved "160" on one side, contains megestrol 160 mg. Nonmedicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose, magnesium stearate, and microcrystalline cellulose.
How should I use this medication?
The recommended dose depends on the condition being treated and body weight.
For people with prostate cancer, the recommended dose is 120 mg as a single daily dose in combination with diethylstilbestrol 0.1 mg.
For people with breast cancer, the usual dose is 160 mg daily. This dose may be divided into 4 equal doses of 40 mg.
For people with cancer of the endometrium, the usual dose is 80 mg to 320 mg daily, which can be divided into 40 mg to 80 mg doses taken 1 to 4 times daily, or 1 to 2 160 mg tablets daily.
For people with cancer or AIDS and appetite loss, muscle wasting, or significant weight loss, the usual adult dose is 400 mg to 800 mg as a single daily dose. People with AIDS usually use the liquid form of this medication, which needs to be shaken well before use.
Megestrol can be taken with or without food.
The effectiveness of megestrol acetate can be assessed after 2 months have passed following the start of therapy.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule.Do not take a double dose to make up for a missed one.
The tablets and liquid should be stored at room temperature in a cool, dry place.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Megestrol should not be taken anyone who:
- is sensitive or allergic to megestrol acetate or to any other ingredients of the medication
- is pregnant (first 4 months)
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- hair loss
- increased appetite
- mild blood pressure increase
- mood changes
- nausea or vomiting
- shortness of breath
- swelling of the face, ankles, or feet
- weight gain
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- changes in vaginal bleeding
- dry mouth
- filling or rounding out of face
- frequent urination
- increased blood sugar levels
- increased flow of breast milk
- loss of appetite
- nausea or vomiting
- unusual thirst
- unusual tiredness or weakness
Stop taking the medication and seek immediate medical attention if any of the following occur:
- severe or sudden headache or migraine
- severe or sudden loss of or change in speech, coordination, or vision
- severe or sudden numbness or pain in chest, arm, or leg
- signs of blood clotting problems
- unexplained shortness of breath
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Diabetes: Megestrol can sometimes cause an increase in blood glucose. People with diabetes should monitor their blood sugar levels carefully while taking this medication.
Pregnancy: Megestrol acetate is not recommended for use during the first 4 months of pregnancy. Women should use effective birth control when taking megestrol. If you become pregnant while taking megestrol, tell your doctor right away.
Breast-feeding: It is recommended that women not breast-feed while taking megestrol because of the potential for side effects in the breast-feeding infant.
What other drugs could interact with this medication?
The following medications may affect how megestrol works or increase the risk of side effects:
- testosterone and androgens (for men taking megestrol to treat prostate cancer)
- estrogen (form women taking megestrol for breast or endometrial cancer)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.