Megestrol Acetate for AIDS-Related Weight Loss

Megestrol acetate is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat loss of appetite, severe weight loss, or unexplained significant weight loss in people with acquired immune deficiency syndrome (AIDS).

How Megestrol Acetate Works and How It’s Taken

Megestrol acetate is a hormonelike medicine called a progestin. The exact way it helps with anorexia and cachexia is not known. Anorexia means loss of appetite, and cachexia is severe weight and muscle loss.

Doctors prescribe megestrol acetate for people with AIDS who have anorexia, cachexia, or significant unexplained weight loss. Before treatment starts, doctors should look for other causes of weight loss that may be treatable.

Megestrol acetate comes as an oral suspension, which is a liquid taken by mouth.

Typical Dosing for AIDS-Related Weight Loss

The recommended starting dose of megestrol acetate for adults with AIDS-related anorexia, cachexia, or unexplained significant weight loss is 625 milligrams once a day when using the 125 milligrams per milliliter oral suspension. This is equal to 5 milliliters, or 1 teaspoon, once daily. Shake the bottle well before each dose.

Megestrol acetate oral suspension also comes in other strengths, including 40 milligrams per milliliter. These strengths are not interchangeable because the amount of medicine in each milliliter is different. Always use the dose and volume listed for the exact product you have.

This information is based on prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Megestrol Acetate Side Effects

In clinical studies of megestrol acetate oral suspension in people with AIDS, the most common side effects include:

Nausea
Diarrhea
Erectile dysfunction (impotence)
Rash
Flatulence (gas)
Hypertension (high blood pressure)
Asthenia (weakness or low energy)

Serious Side Effects and Warnings

Megestrol acetate can cause serious side effects that may require immediate medical attention. These include:

Severe allergic reaction — Hypersensitivity reactions can occur, which can include serious allergic symptoms.
Adrenal insufficiency — Low adrenal hormone levels can occur, which can cause low blood pressure, nausea, vomiting, dizziness, or weakness.
Diabetes or worsening diabetes — New-onset diabetes mellitus or higher blood sugar can occur.
Fetal harm — This medication can harm your baby if you are pregnant; megestrol acetate should not be used in pregnancy.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Megestrol Acetate

Before starting megestrol acetate, your doctor should make sure you are not pregnant if you are able to become pregnant. A pregnancy test should be done before treatment begins.

Tell your doctor if you have a history of blood clots. Megestrol acetate should be used with caution in people who have had thromboembolic disease, which means blood clots in a vein or other blood vessel.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Do not take megestrol acetate if you:

Are pregnant
Have had an allergic reaction, also called hypersensitivity, to megestrol acetate or any ingredient in the medicine

Megestrol acetate may harm your baby if you are pregnant. If you can become pregnant, use effective birth control while taking it. Tell your healthcare provider if you are pregnant or think you may be pregnant.

Do not breastfeed while taking megestrol acetate. People with HIV-1 are advised not to breastfeed because HIV-1 can pass to a baby through breast milk. Megestrol acetate is also present in human milk.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is megestrol acetate for AIDS-related weight loss?

Clinical studies found that megestrol acetate helped some people with AIDS-related anorexia, cachexia, and significant weight loss gain weight and improve their appetite over 12 weeks.

In one study, 64 percent of people taking 800 milligrams a day and 57 percent taking 400 milligrams a day gained at least 2.3 kilograms. This compared with 24 percent of people taking a placebo, which did not contain megestrol acetate.

In another study, people taking megestrol acetate gained an average of 5.1 kilograms by week 12, while people taking placebo lost an average of 1.0 kilogram. Appetite improved in 67 percent of people taking megestrol acetate compared with 38 percent taking placebo.

How long does Megestrol acetate take to work?

The clinical studies measured changes in weight and appetite over 12 weeks. It does not say exactly how soon a person may notice an improvement in appetite or weight after starting megestrol acetate.

Can megestrol acetate interact with other medicines?

Yes. Megestrol acetate can interact with some medicines.

One important interaction is with indinavir, a medicine used to treat HIV. Megestrol acetate can lower the amount of indinavir in the body. Because of this, a healthcare provider may consider increasing the indinavir dose when the two medicines are taken together.

Megestrol acetate has also been studied with zidovudine, another HIV medicine, and rifabutin, an antibiotic used to treat or prevent certain bacterial infections. Taking megestrol acetate with either of these medicines does not require a dose adjustment for zidovudine or rifabutin.

Always follow your healthcare provider’s instructions when taking megestrol acetate with other medicines.