Fatigue and cancer drugs

What is fatigue?

Fatigue means feeling very tired, exhausted and lacking energy. It can be a symptom of the cancer or a side effect of treatment such as cancer drugs.

Doctors use many types of drugs to treat cancer. Some of these cancer drugs can make you feel tired and lack energy.

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 including your physical, emotional, social and mental well-being. It also affects if you are able to do your usual activities.

Fatigue is one of the most common side effects of cancer treatment. 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

Other drugs you might have with cancer treatment that can cause tiredness include some painkillers, anti sickness drugs and steroids.

Some other factors that can cause cancer related fatigue are:

• advanced cancer

• uncontrolled pain

• low red blood cells (anaemia)

• poor diet due to loss of appetite

• dehydration

• menopause

• low or high thyroid gland levels

• other health problems (comorbidities), for example, heart problems

• depression or anxiety

• 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. Fatigue from cancer drugs 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

Find out more about cancer drugs

Symptoms of fatigue

The symptoms of fatigue are very general and they could be for other reasons. The following is a list of some symptoms you might have:

• feeling weak in most areas of your body

• finding it difficult to concentrate

• difficulty falling or staying asleep or sleeping too much

• being emotionally overly sensitive

• lack of motivation

• difficulty in remembering things

• generally feeling unwell or sluggish without a clear reason

• difficulty completing tasks you usually can do

Let your doctor or nurse know if you have any of these signs.

Find out how your healthcare team assesses if you have fatigue

Effects of fatigue

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 generally doesn’t go away even after resting or sleeping.

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 (about 30%) may have fatigue for a few years after cancer treatment. This is called chronic fatigue. Chronic means long lasting.

You, your relatives and friends 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.

Drugs that cause fatigue

Different drugs cause tiredness in different ways.

What can help

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.

Feeling tired because of low red blood cells (anaemia)

You might have a blood transfusion if you are feeling tired because you are anaemic.

Some people can have a drug to help reduce anaemia. This drug is called EPO and has different names, this includes:

• epoetin alfa (Eprex)

• epoetin beta (NeoRecormon)

• epoetin zeta (Retacrit)

• darbepoetin alfa (Aranesp)

EPO is a manmade copy of the hormone erythropoietin that is made by your kidneys. It stimulates the bone marrow 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 in people with cancer having chemotherapy.

Find out more about blood, bone marrow and cancer drugs

Feeling tired because of sleeping problems, anxiety, or depression

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.

Tips for tiredness

• 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 as 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. A balanced diet means eating foods from all the food groups that your body needs.

• Avoid alcohol and caffeine.

• Learn to manage fatigue. Get help with shopping and housework, and don’t try to do it all yourself.

Find out about the different ways to manage and treat fatigue