Last updated on RxList: 8/11/2020
Megace Side Effects Center

What Is Megace?

Megace (megestrol acetate, USP) Oral Suspension is a man-made chemical similar to the female hormone progesterone used to treat loss of appetite and weight loss because of disease, and is also used in the treatment of advanced breast cancer and endometrial cancer. Megace is available in generic form.

What Are Side Effects of Megace?

Common side effects of Megace include:

Women may experience changes in menstrual periods, including unpredictable vaginal bleeding.

Dosage for Megace

The recommended adult initial dosage of Megace Oral Suspension is 800 mg/day (20 mL/day).

What Drugs, Substances, or Supplements Interact with Megace?

Megace may interact with insulin or oral diabetes medicine and may decrease the effects of these medications, and blood sugar levels may increase. If you have diabetes, monitor blood sugar and talk to your doctor if you notice unusual changes. Megace may interact with indinavir, or insulin or oral diabetes medications. Tell your doctor all medications and supplements you use.

Megace During Pregnancy and Breastfeeding

Megace must not be used during pregnancy. It may cause harm to a fetus. Women of childbearing age should use birth control while using this medication. This medication may pass into breast milk and could have undesirable effects on a nursing infant. Breast-feeding is not recommended while using this drug.

Additional Information

Our Megace (megestrol acetate, USP) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Megace Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these side effects during or after your treatment with megestrol:

  • chest pain, sudden cough, wheezing, rapid breathing, coughing up blood;
  • swelling, warmth, or redness in an arm or leg;
  • increased thirst, increased urination, dry mouth, fruity breath odor;
  • weight gain (especially in your waist and upper back);
  • muscle weakness, tiredness, feeling light-headed;
  • skin discoloration, thinning skin, increased body hair; or
  • mood changes, menstrual changes, sexual changes.

Common side effects may include:

  • nausea, gas, diarrhea;
  • increased blood pressure;
  • impotence, sexual problems;
  • rash; or
  • weakness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Megace (Megestrol Acetate)


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Megace Professional Information


Clinical Adverse Events

Adverse events which occurred in at least 5% of patients in any arm of the two clinical efficacy trials and the open trial are listed below by treatment group. All patients listed had at least one post baseline visit during the 12 study weeks. These adverse events should be considered by the physician when prescribing MEGACE Oral Suspension.

ADVERSE EVENTS % of Patients Reporting

Megestrol Acetate, mg/day
No. of Patients
Trial 1
Trial 2
Open Label Trial
Diarrhea 15 13 8 15 8 6 10
Impotence 3 4 6 14 0 4 7
Rash 9 9 4 12 3 2 6
Flatulence 9 0 1 9 3 10 6
Hypertension 0 0 0 8 0 0 4
Asthenia 3 2 3 6 8 4 5
Insomnia 0 3 4 6 0 0 1
Nausea 9 4 0 5 3 4 5
Anemia 6 3 3 5 0 0 0
Fever 3 6 4 5 3 2 1
Libido Decreased 3 4 0 5 0 2 1
Dyspepsia 0 0 3 3 5 4 2
Hyperglycemia 3 0 6 3 0 0 3
Headache 6 10 1 3 3 0 3
Pain 6 0 0 2 5 6 4
Vomiting 9 3 0 2 3 6 4
Pneumonia 6 2 0 2 3 0 1
Urinary Frequency 0 0 1 2 5 2 1

Adverse events which occurred in 1% to 3% of all patients enrolled in the two clinical efficacy trials with at least one follow-up visit during the first 12 weeks of the study are listed below by body system. Adverse events occurring less than 1% are not included. There were no significant differences between incidence of these events in patients treated with megestrol acetate and patients treated with placebo.

Body as a Whole: abdominal pain, chest pain, infection, moniliasis and sarcoma

Cardiovascular System: cardiomyopathy and palpitation

Digestive System: constipation, dry mouth, hepatomegaly, increased salivation and oral moniliasis

Hemic and Lymphatic System: leukopenia

Metabolic and Nutritional: LDH increased, edema and peripheral edema

Nervous System: paresthesia, confusion, convulsion, depression, neuropathy, hypesthesia and abnormal thinking

Respiratory System: dyspnea, cough, pharyngitis and lung disorder

Skin and Appendages: alopecia, herpes, pruritus, vesiculobullous rash, sweating and skin disorder

Special Senses: amblyopia

Urogenital System: albuminuria, urinary incontinence, urinary tract infection and gynecomastia


Postmarketing reports associated with MEGACE Oral Suspension include thromboembolic phenomena including thrombophlebitis and pulmonary embolism, and glucose intolerance (see WARNINGS and PRECAUTIONS).

Read the entire FDA prescribing information for Megace (Megestrol Acetate)

© Megace Patient Information is supplied by Cerner Multum, Inc. and Megace Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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