Reviewed on 9/22/2021

What Is Megace Used For?

Megestrol 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.

Megestrol is available under the following different brand names: Megace and Megace ES.

Dosages of Megestrol

Dosage Forms and Strengths


  • 20 mg
  • 40 mg

Oral Suspension

  • 200 mg/5mL
  • 625 mg/5mL

Dosage Considerations – Should be Given as Follows:

AIDS-Related Cachexia

  • Megace: 800 mg/day orally
  • Megace ES: 312.5-625 mg/day orally

Breast Cancer

  • 40 mg orally every 6 hours

Endometrial Cancer

  • 40-320 mg/day orally in divided doses; evaluate efficacy after 2 months of treatment; up to 800 mg/day may be used

Cancer-Related Cachexia (Off-label)

  • 480-600 mg/day orally

Dosing Modifications

  • Renal impairment: Use with caution; in normal renal function, 57-78% is excreted in urine within 10 days
  • Pediatric: Safety and efficacy not established


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What Are Side Effects Associated with Using Megace (Klonopin)?

Side effects associated with use of Megace, include the following:

  • Changes in appetite
  • Decreased sexual ability/desire
  • Diarrhea
  • Fever
  • Gas (flatulence)
  • High blood pressure (hypertension)
  • Hot sweats
  • Impotence
  • Indigestion
  • Missed menstrual periods, breakthrough bleeding, change in menstrual flow, spotting
  • Mood swings
  • Nausea
  • Skin rash
  • Stomach upset
  • Sweating
  • Trouble having an orgasm
  • Trouble sleeping (insomnia)
  • Vomiting
  • Weakness
  • Weight gain

Serious side effects of megestrol include:

Postmarketing side effects of megestrol reported include:

  • Weakness/lack of energy
  • Rash
  • Impotence
  • Overdose may cause shortness of breath, cough, unsteady gait, listlessness, chest pain

This document does not contain all possible common side effects and other side effects may occur. Check with your physician for additional information about side effects of this drug.

What Other Drugs Interact with Megace (Klonopin)?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

  • Megestrol has no known severe interactions with other drugs.
  • Megestrol has no known serious interactions with other drugs.
  • Moderate interactions of megestrol include:
  • Mild interactions of megestrol include:

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more health information about this medicine.

What Are Warnings and Precautions for Megace?


  • This medication contains megestrol. Do not take Megace or Megace ES if you are allergic to megestrol or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately


  • Known or suspected pregnancy
  • Acute thrombophlebitis, thromboembolic disorder, breast cancer
  • Undiagnosed abnormal genital bleeding
  • Prophylaxis of weight loss
  • Documented hypersensitivity
  • May induce vaginal bleeding in women

Effects of Drug Abuse

  • Overdose may cause shortness of breath, cough, unsteady gait, listlessness, chest pain

Short-Term Effects

  • See "What Are Side Effects Associated with Using Megace (Klonopin)?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Megace?”


  • Diabetes mellitus.
  • History of thromboembolic disease.
  • Not to be used as prophylaxis against weight loss or as diagnostic test for pregnancy.
  • Adrenal insufficiency may occur in patients receiving or being withdrawn from long-term megestrol treatment.
  • Megestrol is a progesterone derivative which may induce vaginal bleeding in women.
  • Cushing syndrome reported with therapy.

Pregnancy and Lactation

  • Use megestrol during pregnancy only in LIFE-THREATENING emergencies when no safer drug is available. There is positive evidence of human fetal risk.
  • Megestrol is not safe for use while breastfeeding; do not nurse.


What is HIV? See Answer
Medscape. Megestrol.
RxList. Megace.

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