Side effects of cancer drugs
Some cancer drugs can cause tiredness (fatigue). But there are things you can do and people that can help.
Doctors use many types of drugs to treat cancer. But some cancer drugs can make you feel tired and low on energy. This is also called cancer fatigue.
You might find that your tiredness goes on for most of the time. And that resting does not help you to feel better. As a result, it affects your quality of life on many levels, as you can’t do your usual activities.
Cancer tiredness is one of the most common side effects of cancer treatment. It affects between 15 and 90 out of every 100 people (15 to 90%). Tiredness in advanced cancer affects around 75 out of every 100 people (75%). Some people taking cancer drugs say severe tiredness is the most disruptive side effect.
Cancer drugs that can cause tiredness are:
chemotherapy
targeted cancer drugs
immunotherapy
hormone therapies
painkillers
anti sickness drugs
steroids
Other factors that can cause cancer tiredness are:
advanced cancer
uncontrolled pain
low red blood cells (anaemia)
metabolic problems, for example, loss of appetite, menopause or an underactive thyroid gland
other health problems (comorbidities), for example, heart problems
depression, anxiety and sleeping problems
Even if a drug can cause tiredness, it may not affect you that way. Drugs affect people in different ways and it is not possible to tell in advance who will feel very tired. It depends on:
the drug or combination of drugs you are having
the dose
how you react to the drug
how you have reacted to drug treatment in the past
Tiredness often happens as a group of symptoms, for example:
pain
depression
difficulty sleeping
symptoms of menopause
Tiredness can cause any of the symptoms below, but they can also be due to other things. Let your doctor know if you have any of these signs:
feeling weak in most areas of your body
finding it hard to concentrate
difficulty falling or staying asleep or sleeping too much
being emotionally overly sensitive
Tiredness as a result of cancer treatment can be very frustrating. Some people say it is the most difficult side effect to deal with. It might not go away even after resting or sleeping.
Tiredness can affect you mentally, physically, emotionally, spiritually and socially. Everyday life can be hard work. You might not feel like cooking, cleaning, having a bath or shopping.
With some cancer drugs, fatigue may go on for weeks or months after you have finished treatment. Around 30 out of every 100 people (30%) may have fatigue for a few years after cancer treatment. This is called chronic fatigue. Chronic means long lasting.
You and your relatives may underestimate how much tiredness can affect your daily life. Doctors can sometimes overlook it. You might feel that healthcare professionals have left you to cope alone. So, telling your doctor or specialist nurse is important if you are very tired and have no energy.
Different drugs cause tiredness in different ways.
Many people with cancer don’t tell their doctor or nurse about their tiredness. Sometimes people think they just need to get on with it. Despite it being hard sometimes to treat the actual cause of your tiredness, it is still important to tell your doctor or specialist nurse about it. They can try things to help you.
You might have a blood transfusion if you are feeling tired because you are anaemic.
A drug called epoetin (EPO) can help reduce anaemia in some people. EPO is a manmade copy of a hormone called erythropoietin made by your kidneys. It stimulates the body to make more red blood cells and can reduce fatigue.
The National Institute for Health and Care Excellence (NICE) recommends EPO for treating low red blood cells (anaemia) in people with cancer having chemotherapy.
Find out more about blood, bone marrow and cancer drugs
Your cancer treatment can also stop your bone marrow from making white blood cells for a while. This can make you less able to resist infection. It can also make you feel tired.
Tiredness, depression, anxiety and problems sleeping often appear together in some people. Researchers think there is a link between cancer tiredness and depression. Sleeping problems, anxiety or depression may make your tiredness worse. But extreme tiredness can also cause emotional distress in some people.
A short course of sleeping tablets might help. It can help to get you back into your sleeping pattern. Your doctor might suggest anti depressants if depression is causing you sleeping problems. You need to take these for a few months to get the most out of them. Most anti depressants take a few weeks to start to work. Talk to your doctor or nurse if you feel depressed.
Sleeping problems, depression and tiredness can be difficult to cope with. But there are things you can do and people that can help.
Keep a diary of your symptoms every day. You might find that, generally, you get the same symptoms on the same days during each cycle. Knowing this can help you to plan your life around your symptoms. So, rest on the days that you know you will feel tired and do activities on the days you won’t feel tired.
Do some gentle physical activity each day, such as a short walk.
Keep to a regular sleep routine, going to bed and getting up at the same time every day.
If you need to nap, try to sleep for around 30 minutes.
Get support from other people. Knowing others are there to help can be a real energy booster.
Don’t push yourself too hard. Rest when you begin to feel tired.
Eat a well balanced diet to try to keep your energy levels up.
Avoid alcohol and caffeine.
Learn to manage fatigue. Get help with shopping and housework, and don’t try to do it all yourself.
Last reviewed: 30 May 2023
Next review due: 30 May 2026
Cancer and its treatment can cause extreme tiredness known as fatigue. There are ways this can be treated.
There are different ways to manage fatigue and the symptoms you might have. It is important to tell your nurse or doctor if you think you may have fatigue.
Cancer drugs have side effects and these can vary from person to person. But there are things that you can do to help you cope.
There are many different types of cancer drugs. Some treat cancer, and others help to relieve symptoms such as sickness and pain. The type of drugs you need for your cancer depends on what type of cancer you have.
Treatments can include surgery, radiotherapy and drug treatments (such as chemotherapy, hormone therapy or targeted cancer drugs). Find out about treatments and how to cope with side effects.
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