About cancer and painkillers

Painkillers are medicines to manage pain. They are also known as analgesics. There are many types available and different ways of taking them. Your medical team will do a pain assessment to find the right drug or combination of drugs for you.

Some people with cancer have constant pain, so they need to take painkillers regularly to keep the pain under control. If this is your situation and you are prescribed painkillers, it is important to take them at regular intervals. This is to make sure the medicines work as well as possible.

It is important to tell your doctor or nurse if your pain does not get better, or gets worse. Do not let your pain increase until it becomes severe. Severe pain can cause fear, anxiety and make it difficult to sleep. These things can make the pain worse and more difficult to control.

Ways of taking painkillers

There are a number of ways that painkillers can be taken including:

  • Tablets and capsules

    Painkillers are mostly taken by mouth, either as tablets or capsules. If you find it hard to swallow, many painkillers are available as liquids and some can be dissolved in water. If you have a feeding tube, some liquid or soluble painkillers can be given through it.

  • Skin patches and gels

    Painkillers can be absorbed through the skin. Patches put onto the skin slowly release painkiller over a few days. You can rub a gel onto the skin to relieve pain in one area.

  • Buccal and sublingual medicines

    These are painkillers that are absorbed through the lining of your mouth, so they don’t have to be swallowed. They are either put in the side of your cheek (buccal) or under the tongue (sublingual).

  • Suppositories

    These are inserted into the back passage (rectum).

  • Nasal sprays

    Some painkillers can be sprayed into the nose.

  • Gas and air (Entonox®)

    This is a painkiller that’s breathed in. It is sometimes used during painful procedures, such as a bone marrow test or dressing change. Gas and air is only available in hospitals.

  • Injections

    Some painkillers can be given by injection, either into a muscle, vein or under the skin (subcutaneously).

Having infusions

Painkillers can also be given by infusion over a period of time. There are different ways of giving painkillers by infusion:

  • Subcutaneous infusion

    This involves giving a continuous dose of a drug or drugs through a fine needle placed just under the skin. A small, portable pump called a syringe pump is used to give the drugs.

  • Intravenous infusion

    After surgery, some people may have a continuous dose of painkiller given into a vein (intravenously) through a pump. This is called patient-controlled analgesia (PCA). It is only used in hospital for short-term pain control.

  • Epidural and intrathecal analgesia

    These may be used to relieve pain after surgery. Sometimes they can be used to help people with cancer pain that is difficult to treat. An anaesthetist puts a fine tube into your back and connects it to a pump that gives you a constant dose of medicine.

Having a syringe pump

A syringe pump is a small, portable pump that can be used to give you a continuous dose of your painkiller and other medicines. You may use one if you are being sick or you can’t swallow. Your doctor or nurse will let you know if you need a syringe pump.

The painkiller is put into the syringe, and the syringe is put into the pump. It is attached by a long tube to a fine needle or cannula that is placed just under the skin. A small dose of the drug is then released at a constant rate for as long as you need it. The syringe is usually changed every 24 hours by a nurse.

Syringe pumps are portable so you can move around as usual. The pumps are battery powered and can clip onto a belt, or fit into a pocket or bag. Or they can be placed in a specially designed holster (holder) that fits under your arm. Other medicines, such as anti-sickness drugs, can also be given through the syringe pump.

Some people worry that if they have advanced cancer and need a syringe pumps, this could shorten their life. This isn’t true. A syringe pump is simply a different way of giving drugs, at the dose you need to control your symptoms.

Types of painkiller

Pain is often described as being mild, moderate or severe. Different types of painkillers are effective for the different levels of pain. Once your doctors and nurses have assessed your pain they will prescribe the best painkillers to help control it. They may also prescribe other medicines to take with the painkillers to help reduce pain.

  • Mild painkillers called non-opioid drugs are often used for mild pain.
  • Strong painkillers called opioid drugs are usually used to relieve moderate to severe pain. Sometimes opioids are used to treat mild pain.

At first, you usually take a short-acting painkiller. These provide quick pain relief that lasts for a short amount of time. The dose can easily be adjusted until your pain is well controlled.

When the doctor knows how much of the painkiller you need to control your pain, you will usually change to a long-acting drug. Long-acting painkillers are usually slower to control the pain, but are effective for a longer period of time. They are also called slow-release painkillers.

Mild painkillers (non-opioid drugs)

Mild painkillers such as paracetamol and anti-inflammatory drugs can successfully treat mild pain.

  • Paracetamol

    You can buy paracetamol from a pharmacy or supermarket. It has few side effects, but it is very important not to take more than the recommended dose. Higher doses can damage the liver. Paracetamol does not reduce inflammation.

  • Anti-inflammatory drugs

    Anti-inflammatory drugs such as ibuprofen help reduce inflammation and swelling. They are good for treating pain in the skin, muscle and bone. You can usually buy these from a pharmacy or supermarket. Check with your doctor or nurse before taking these types of medicines. Anti-inflammatory drugs can cause indigestion and may irritate the lining of the stomach, so it’s important to take them after a meal or snack. Your doctor may prescribe another medicine to help protect your stomach.

When taking these drugs, always check the recommended dose on the packet and never take a higher dose.

Be aware that some other medicines, such as cold and flu remedies, may also contain paracetamol or anti-inflammatory drugs. If you are taking painkillers, you should be careful which other medicines you take, so that you don’t take more than the recommended doses. If you are unsure, check with a pharmacist before buying any over-the-counter medicines.

Strong painkillers (opioid drugs) for mild to moderate pain

Strong painkillers such as dihydrocodeine (DF118 Forte®, DHC Continus®), codeine phosphate and tramadol can treat mild to moderate pain.

These drugs are often combined with paracetamol in a single tablet. For example, codeine and paracetamol make the painkiller co-codamol.

Most of these drugs are only available with a prescription. There is a limit to the number of tablets you can take in one day. If your pain is not controlled, it is important to let your doctor know so that they can give you stronger painkillers.

Strong painkillers (opioid drugs) for moderate to severe pain

Stronger painkillers such as morphine, fentanyl and oxycodone are used to treat moderate to severe pain. Buprenorphine and diamorphine are also commonly used. Other drugs, such as tapentadol, hydromorphone, methadone and alfentanil are less commonly used.

You will usually start by having a low dose. The doctors will increase it gradually to a dose that controls your pain. If your pain increases or decreases, the dose of your painkiller can be changed.

It can take a few days to adjust to taking a strong opioid painkiller, or to taking a higher dose. If you have side effects, tell your doctor or nurse.

Other drugs may be used together with strong painkillers. For example, paracetamol or ibuprofen are often also prescribed. If your doctor or specialist nurse suggests this, it is important to take these as well as your strong painkiller.


You can take morphine as:

  • short-acting tablets (Sevredol®)
  • short-acting syrups (Oramorph®)
  • a short-acting injection
  • suppositories, which are usually short-acting
  • long-acting granules to mix with water (MST Continus®)
  • long-acting tablets and capsules (Morphgesic® SR, MST Continus®, MXL®, Zomorph®).

To begin with, you usually take a short-acting type of morphine every 2 to 4 hours. Your doctor or specialist nurse will explain to you how often to take the drug. It’s usually taken as a tablet or a liquid. Liquid morphine has a bitter taste but mixing it with a fruit drink can help.

When the doctor knows how much morphine you need to control your pain, you will usually change to long-acting drugs. These release the morphine dose very slowly over a period of either 12 or 24 hours, depending on which type you are taking. You may still need to take short-acting morphine in between if you get breakthrough pain.

You may have morphine as an injection or as an infusion using a syringe pump. This is useful if you are feeling sick or vomiting. Occasionally, morphine suppositories are used.


You can have fentanyl in different ways.

Fentanyl patches

These look like waterproof plasters. You stick them onto your skin and the drug is slowly released through the skin. The patches are changed every 3 days and each new patch is put on a different area of skin.

When you first use the patch, it takes around 12 to 24 hours for the fentanyl to reach its level in the blood. During this time, you’ll usually need to take a short-acting opioid, such as morphine, to keep the pain under control.

You should place patches on parts of your body that are not hairy. Write the date on the patch so you remember when to change it. Patches can sometimes cause a slight skin rash. Try to stop the patch getting hot by protecting it from the sun, hot water, heat pads or hot water bottles. Let your doctor or specialist nurse know if you have a temperature, as it may affect how the medicine is absorbed through your skin.

Buccal, sublingual or nasal fentanyl

There are three types of buccal fentanyl:

  • a short-acting lozenge (Actiq®)
  • a tablet (Effentora®)
  • a dissolvable film (Breakyl®).

You put buccal medicines in your mouth between your cheek and gum. The drug is absorbed from here into the body. They work best for breakthrough pain.

Fentanyl can also be given as a sublingual tablet (Abstral®, Recivit®) that you put under the tongue. Or you can have it as a nasal spray (Instanyl®, Pecfent®).

Other strong painkillers

  • Oxycodone

    You can take oxycodone by mouth as short-acting capsules or liquid (Lynlor®, Oxycodone®, OxyNorm®, Shortec®) every 4 to 6 hours. Or you can have long-acting tablets (Abtard®, Longtec®, OxyContin®, Reltebon®, Targinact®) every 12 hours. Oxycodone can also be given by injection, or as an infusion using a syringe pump. You may have oxycodone if you can’t have morphine or if it doesn’t work well for you.

  • Buprenorphine

    This may be given as:

    • a skin patch (Hapoctasin®, Transtec®) that you change every 3 days
    • a skin patch (BuTrans®) that you change every 7 days
    • a tablet (Gabup®, Prefibin®, Subutex®, Temgesic®, Tephine®) that you dissolve under the tongue every 6 to 8 hours.


  • Diamorphine

    You may have diamorphine if you can’t swallow and need to have painkillers by injection, or as an infusion using a syringe pump. Diamorphine is converted to morphine in the body.

  • Tapentadol

    Tapentadol (Palexia®) is available as:

    • short-acting tablets
    • short-acting syrup
    • long-acting tablets.


  • Hydromorphone

    Hydromorphone is available as short-acting capsules (Palladone®) and long-acting capsules (Palladone® SR).

  • Methadone

    Methadone may be given as:

    • a tablet (Physeptone®)
    • a syrup
    • an injection (Physeptone®, Synastone®).

    It is usually only given under close supervision from a specialist palliative care doctor or pain doctor. Methadone may help reduce nerve pain.

  • Alfentanil

    Alfentanil (Rapifen®) is another strong painkiller that is only given by injection or as an infusion using a syringe pump. It is more likely to be used if someone’s kidneys are not working well.

Side effects of strong painkillers

As with most medicines, some people will get side effects. These won’t affect everyone taking strong painkillers. Here are some of the more common ones:

  • Constipation

    Most strong painkillers cause constipation. If you’re taking strong painkillers, you should also take a laxative throughout your treatment. Some laxatives soften stools and make them easier to pass. Others stimulate the bowel to push the stools along more quickly. Taking a combination of these two types of laxative is often best for preventing constipation.

  • Sickness

    You may feel sick when you first start taking opioid painkillers. You may need to take an anti-sickness (anti-emetic) drug for at least the first week of treatment. If you have sickness that doesn’t stop after seven days, let your doctor know. You may need to change to another painkiller.

  • Drowsiness

    Drowsiness usually decreases within a few days once you are used to the dose. If you start to get drowsy when you have been taking strong painkillers for a while, you should tell your doctor or specialist nurse. This can sometimes happen if you are having other treatments to shrink the cancer that may have helped to reduce your pain.

  • Feeling tired

    Strong painkillers can make you feel tired. You should not drive if you have recently started taking strong painkillers or if you have increased the dose. This is because they may make you drowsy and slow your reactions.

  • Dry mouth

    Strong painkillers can make your mouth dry. Chewing gum or using products containing artificial saliva can help. Tell your doctor or nurse if you have a dry mouth.

  • Drug tolerance

    Sometimes, the body can get used to a painkiller so that more of the drug is needed to get some level of pain control. This is called drug tolerance. Your doctor or nurse may need to increase the amount of painkiller you take, or give you a different type. Tolerance is very different to addiction.

    Many people who are prescribed strong painkillers are concerned about becoming addicted. This is unlikely to happen. When painkillers are prescribed properly, most people do not get the high feeling that can result in addiction.

  • Other effects

    If the dose of a strong painkiller is too high, it can cause other symptoms. It could make you confused, forgetful, have vivid dreams and hallucinations (seeing things that are not real), have low blood pressure and slow, deep breathing. You may also feel dizzy or faint. Let your doctor know straight away if you have any of these side effects.

Remember that although all strong painkillers cause similar side effects, some may suit you better than others. If your pain is not well controlled, or if side effects are a problem, tell your doctor or nurse. They may change your dose or give you another type of strong painkiller

Other medicines to help control pain

You may be prescribed other medicines to take with painkillers. These are known as adjuvant drugs and may include the following:

  • Bisphosphonates

    People who have pain from cancer that has spread to the bones may find drugs called bisphosphonates helpful. As well as helping to reduce pain, they can also strengthen the affected bones. You can have them as a drip into a vein, usually once a month, or as tablets.

  • Denosumab

    Denosumab (Prolia®, Xgeva®) is a treatment that reduces bone breakdown. It may be used to lower the risk of broken bones, and to relieve pain if cancer has spread to the bones. You have it as an injection just under the skin, every four weeks.

  • Steroids

    You usually have steroids as tablets, but they can also be given as an injection. They can reduce swelling and pain caused by a tumour pressing on a part of the body. There are many types of steroids. Usually people are given prednisolone or dexamethasone.

  • Antibiotics

    When pain is caused by an infection, for example an infected wound, your doctor may prescribe anti-biotics to treat the infection.

  • Anti-epileptic and anti-depressant drugs

    Some anti-epileptic drugs (such as gabapentin, Neurontin®; or pregabalin, Lyrica®) and some low-dose anti-depressants (such as amitriptyline) can help reduce pain caused by nerve damage. This type of pain is called nerve pain. These medicines are usually taken as tablets or capsules.

    The dose of these medicines may need to be gradually increased over a few days or weeks to control the pain. This means it’s important to continue taking them, even if they don’t work immediately.

    Some people worry that if they are given anti-depressants for nerve pain, it’s because their doctor thinks they’re depressed. This is not the reason. Research has shown that low doses of anti-depressants are effective for nerve pain.

    The anti-depressant amitriptyline can make some people feel sleepy or slightly ‘hungover’. If this happens to you, tell your doctor or nurse. You could take the dose at night to stop you feeling drowsy during the day.

  • Muscle relaxants

    If muscle spasms are making your pain worse, you may have a short course of a drug to help relax the muscles.

    Commonly used muscle relaxants are:

    • diazepam (Valium®)
    • clonazepam (Rivotril®)
    • baclofen (Lioresal®)
    • hyoscine butylbromide (Buscopan®).


Finding the right medicine for you

You may have other medicines that are not mentioned here. Ask your doctor or specialist nurse if you have any questions or are unsure about any of your prescribed medicines.

Sometimes it may take a little while to find the drugs that suit you best and relieve your pain. Talk to your doctor or nurse if you are still in pain or the side effects are bothering you.

How we can help

Macmillan Grants

If you have cancer, you may be able to get a Macmillan Grant to help with the extra costs of cancer. Find out who can apply and how to access our grants.

0808 808 00 00
7 days a week, 8am - 8pm
Email us
Get in touch via this form
Chat online
7 days a week, 8am - 8pm
Online Community
An anonymous network of people affected by cancer which is free to join. Share experiences, ask questions and talk to people who understand.
Help in your area
What's going on near you? Find out about support groups, where to get information and how to get involved with Macmillan where you live.