Medicines for diet problems

There are medicines that can help with weight loss, cachexia Open a glossary item and digestion problems.

Appetite stimulants

Appetite stimulants are for people who have lost a lot of weight or have cachexia and have a loss of appetite. They work for some people.

Doctors can use the following hormone drugs:

  • megesterol acetate (Megace)

  • medroxyprogesterone acetate (Depo Provera and Provera)

These medicines increase appetite and food intake. So they can be helpful for people with cancer who have nutritional problems. These drugs might also help you put on weight, but this can take up to 8 weeks. 

Side effects of appetite stimulants

The side effects are usually very mild and you may not have any at all. But they can cause:

  • nausea (feeling and being sick)

  • headaches

  • swelling from fluid build up

  • tummy (abdominal) pain

  • blood clots

  • erectile dysfunction

  • vaginal bleeding

  • difficulty sleeping (insomnia)

  • feeling dizzy, shaky or nervous

  • constipation

  • hot flushes and sweats

  • tiredness

  • difficulty breathing

  • a rounded face

  • high blood pressure

  • a rise in blood sugar levels

You need to check your blood sugar levels more when taking these drugs if you have diabetes. You might need to adjust the dose of your diabetes medicine.

You should not take these drugs if you are pregnant or thinking about getting pregnant.

Steroids

Doctors use steroids for many different illnesses and conditions. The body naturally makes them. They are also made artificially and used as medicines. They come as tablets, liquids or injections.

Steroids can help to control chemotherapy sickness in people with cancer. They can also improve appetite and food intake. The steroid medicines doctors use are:

  • methylprednisolone
  • dexamethasone

Doctors sometimes use steroids to help people gain weight. But there can be problems if you take them long term. Steroids only improve your appetite for a short amount of time.

After taking them for a few weeks, they begin to interfere with the production of protein in your muscles. If used long term, they can cause muscle wasting. So, you need to use steroids under the supervision of your doctor.

Side effects of steroids

Some side effects of steroids are:

  • increased risk of infection

  • difficulty sleeping, particularly if you take them late in the day

  • indigestion

  • high blood sugar levels, especially if you have diabetes

  • mood changes and suicidal thoughts in some people

  • a burning or tingling sensation around your bottom during a steroid injection into a vein (intravenous)

Anti sickness drugs (anti emetics)

Feeling and being sick is best controlled with medicines. These drugs are called anti sickness drugs, anti nausea drugs or anti emetics.

There are many anti sickness drugs to choose from. These include:

  • metoclopramide

  • domperidone

  • cyclizine

  • ondansetron

  • apretitant

Tell your doctor or pharmacist if one drug does not work for you. They can often suggest another you can try.

In some people, sickness from chemotherapy does not get better with anti sickness drugs. In these situations, doctors can use a drug called nabilone. Nabilone is a man made (synthetic) form of cannabis. You might have to stay in hospital to have nabilone.

Side effects of anti sickness drugs

Let your doctor or pharmacist know as soon as possible if you get side effects from your anti sickness drug.

There are many different types of anti sickness medicine. These can all have different side effects. Some general side effects are:

  • headaches

  • constipation

  • weakness

  • tiredness

Drugs for diarrhoea

The most commonly used drugs for diarrhoea are:

  • codeine phosphate

  • Ioperamide (Imodium)

These drugs slow the movement of the bowel. Codeine phosphate is a painkilling drug. But it is also used to treat severe diarrhoea because it causes constipation.

Side effects of drugs for diarrhoea

Side effects of anti diarrhoea drugs are not common, but they can happen. Tell your doctor if any of these symptoms are severe or do not go away. Some of these symptoms include:

  • dizziness

  • feeling and being sick

  • wind (flatulence)

  • constipation

  • headaches

Drugs for constipation

These are called laxatives. There are different ones that work in different ways:

  • bulk forming laxatives work by swelling up inside your bowel. This softens and increases the amount of stool, which encourages your bowels to open

  • stimulant laxatives work by speeding up bowel movement

  • osmotic laxatives work by drawing more water into your bowel. This makes your stools softer and easier to pass

Side effects of drugs for constipation

Different laxatives have different side effects.

Bulk forming laxatives can cause wind and swelling in the stomach (abdomen). Very rarely they can block up your bowel. So, you should drink plenty of water with these drugs to help prevent it.

Other types of laxatives can cause stomach cramps and wind. Large doses can cause diarrhoea.

The side effects usually go away once your bowels have opened. Contact your doctor if the cramping continues or if you have swelling of your stomach. Also, let them know if you develop diarrhoea.

Painkillers

Painkillers are also called analgesics or analgesia. Severe pain can make you lose your appetite and feel sick. If your pain is under control you are more likely to feel like eating.

  • ESPEN guidelines on nutrition in cancer patients
    J Arends and others
    Clinical Nutrition, 2017. Volume 36. Pages 11-48

  • ESPEN practical guideline: clinical nutrition in cancer  
    M Muscaritoli and others
    Clinical Nutrition, 2021. Volume 40. Pages 2898-2913

  • The Royal Marsden Manual of Clinical and Cancer Nursing Procedures (10th edition, online)
    S Lister, J Hofland and H Grafton 
    Wiley Blackwell, 2020

  • Electronic Medicines Compendium (EMC)
    Accessed October 2023

  • British National Formulary (BNF) - NICE

    Accessed October 2023

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in.

Last reviewed: 
27 Mar 2024
Next review due: 
26 Mar 2027

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