Megestrol acetate (Megace)

Megestrol acetate is a type of hormone treatment. It is also called Megace or megestrol.

It is a treatment for womb, breast, and ovarian cancer that has:

• come back after treatment (recurred or relapsed)

• spread to other parts of the body (secondary or metastatic cancer)

It is also a treatment for poor appetite. Your doctor might suggest you take it if you have lost weight because of cancer or its treatment.

How does megestrol acetate work?

Megestrol acetate is a man-made version of the hormone progesterone. Progesterone is one of the female hormones, but men also make a small amount of it. 

Hormones are natural substances made by glands in our bodies. They are carried around our body in our bloodstream and act as messengers between one part of our body and another.  

Some cancers use hormones to grow or develop. This means the cancer is hormone sensitive or hormone dependent.

Megestrol acetate can interfere with the hormone balance in the body so that the body makes smaller amounts of the hormones that some cancers depend on to grow. It may also interact with other hormones or have a direct effect on the cancer to stop it growing.

How do you have megestrol acetate?

You take megestrol acetate as a tablet. You swallow them whole with a glass of water.

You should take the right dose, not more or less.

Talk to your healthcare team before you stop taking a cancer drug, or if you miss a dose.

How often do you take megestrol acetate?

You usually take megestrol acetate once a day, at the same time each day. Sometimes the dose is divided up, so that you take the tablets a couple of times a day.

When you start taking it you should take them for at least 2 months. This is to find out if they are working. You can take them for as long as the treatment is working and you aren’t experiencing too many side effects.

What are the side effects of megastrol acetate?

Side effects can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

• you have severe side effects 

• your side effects aren’t getting any better

• your side effects are getting worse

Early treatment can help manage side effects better. 

We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.

Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Increased appetite and weight gain

Feeling hungrier can make it difficult to keep your weight down. Your appetite will go back to normal when you stop the treatment but some people may need to make changes to their diet to lose the excess weight.

Talk to your healthcare team about how to safely control your weight.

Hot flushes and sweats

We have some tips for coping with hot flushes in women and hot flushes in men. This information also includes some of the possible treatments. Talk to your doctor if your hot flushes are hard to cope with. They might be able to prescribe some medicines to help.

Shortness of breath

Megestrol acetate can cause you to be short of breath. Tell your doctor or nurse if it happens. 

Changes to your face and appearance

You might develop a rounded, swollen or puffy face, stretch marks, acne or increased facial hair

You might put on weight around your tummy (abdomen).

This can be quite upsetting. Talk to your doctor, pharmacist or nurse about any of these side effects.

High blood pressure

Tell your doctor or nurse if you have headaches, nosebleeds, blurred or double vision or shortness of breath. You have your blood pressure checked regularly.

High blood sugar level

High blood sugar levels can cause headaches, feeling thirsty and blurred vision. You have regular tests to check your blood sugar levels. You may need to check your levels more often if you have diabetes .

Constipation

Constipation is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.

Blood clots

Blood clots can develop in the deep veins of your body, usually the leg. This is called deep vein thrombosis (DVT). A blood clot can be very serious if it travels to your lungs (pulmonary embolism), although this isn’t common.

Symptoms of a blood clot include:

•    pain, redness and swelling around the area where the clot is and may feel warm to touch
•    breathlessness
•    pain in your chest or upper back – dial 999 if you have chest pain
•    coughing up blood

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

• feeling or being sick

• fluid build up causing swelling mainly in the ankles

• vaginal bleeding such as spotting or breakthrough bleeding that is not part of your period

• feeling tired, weak or lacking energy

• hair loss or thinning

• skin rash, the rash may be raised and itchy (hives)

• mood changes - talk to your healthcare team if you are struggling

• losing the ability to have an erection - talk to your doctor for help and advice

• passing wind (flatulence) more often

• weeing more often

• diarrhoea

• high level of calcium in the blood - you'll have regular blood tests to check this

• heart changes causing the heart to not pump well - your doctor will check your heart regularly

• an increase in the signs and symptoms of where your cancer is. This might mean you get pain in the area of the cancer. This is temporary when you first start taking megestrol. Speak with your doctor or nurse they can suggest what painkillers to take

• a weak grip, pain, numbness or tingling in your fingers and thumb (carpal tunnel syndrome)

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do you need to know?

Other medicines, foods and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Pregnancy and contraception

It is unknown whether treatment may or may not harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment. Let your team know straight away if you or your partner become pregnant while having treatment.

Talk to your doctor or nurse about effective contraception you can use during treatment. Ask how long you should use it before starting treatment and after treatment has finished.

Breastfeeding

Don’t breastfeed during this treatment because the drug may come through into your breast milk.

Other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.