Types of painkillers
There are different types of painkillers and ways of taking them. Your medical team will find the best painkiller to help you manage cancer pain.
Types of painkillers to help with cancer pain
Pain is often described as being mild, moderate or severe. Different types of painkillers can be effective for different levels of pain. Once your doctors and nurses have assessed your pain, they will prescribe the best painkillers to help control it. You may also be given other drugs to help relieve pain. These may include steroids and muscle relaxants.
To get your pain under control, you usually start by taking a short-acting painkiller. This will usually work in around 30 minutes. You usually need to take short-acting painkillers every 4 to 6 hours. The dose can be adjusted until your pain is controlled. When the doctor knows the dose you need, they may change you to a slow-release or long-acting painkiller. Long-acting painkillers are usually taken 2 times a day.
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Painkillers for mild pain
If pain is mild, it can often be controlled with simple painkillers such as:
- paracetamol
- non-steroidal anti-inflammatory drugs (NSAIDs) – for example, ibuprofen.
You can buy these drugs from a pharmacy (chemist) or supermarket. Take them as explained on the packet. You may need to take some medicines with food, or after eating.
Other medicines you can buy, such as cold and flu remedies, may also contain paracetamol or anti-inflammatory drugs. Be careful that you do not take more than the recommended dose of any painkillers. If you are unsure, check with a pharmacist before buying any medicines.
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Paracetamol
Paracetamol can be used for most types of mild pain. It does not cause many side effects. But it is very important not to take more than the recommended dose. Higher doses can damage the liver. If you think you have taken too much, tell your doctor or nurse straight away.
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Anti-inflammatory drugs
Non-steroidal anti-inflammatory drugs (NSAIDs) are often used to relieve pain and reduce inflammation and swelling. They may be taken on their own or with other types of painkillers.
Ibuprofen is an NSAID that has different brand names, including Brufen® and Nurofen®. You can buy these drugs from a supermarket or pharmacy. Check with your doctor or nurse before taking NSAIDs. They do not work for everyone. They should not be taken with some medicines.
Other anti-inflammatory medicines, such as diclofenac and naproxen, need to be prescribed by a doctor.
NSAIDs can cause indigestion and may irritate the lining of the stomach. Your doctor may prescribe a drug to help protect your stomach. If you have had problems with your stomach, your doctor may advise taking a different type of painkiller. If you have muscle or joint pain, they may suggest anti-inflammatory skin patches or gel that you rub into the skin.
When taking these drugs, always check the recommended dose on the packet and never take a higher dose.
Painkillers for mild to moderate pain
Doctors usually treat mild to moderate cancer pain with drugs called opioids. These are sometimes called ‘morphine-like’ medicines. There are different types of opioids, and some are stronger than others. Opioid drugs used for mild to moderate pain include:
- codeine phosphate
- dihydrocodeine (DF118 Forte®, DHC Continus®)
- tramadol.
Some drugs combine an opioid with paracetamol. For example, co-codamol is a combination of codeine and paracetamol. There is a limit to the number of these tablets you can take in a day. If you are prescribed a combination drug and it is not controlling your pain, tell your doctor, so they can give you stronger painkillers. Some doctors prescribe a low dose of a stronger opioid to treat mild to moderate pain.
Painkillers for moderate to severe pain
Moderate to severe pain is usually treated with strong opioids. Your doctor usually prescribes a low dose of the opioid drug to start with. They gradually increase the dose until your pain is well controlled.
It can take a few days to adjust to taking a stronger opioid, or a higher dose of opioid.
Tell your doctor or nurse if you have side effects from the painkiller they have prescribed. They may be able to prescribe a different type that does not cause the same side effects.
Your doctor may prescribe other drugs, such as paracetamol or ibuprofen, to take regularly along with strong painkillers.
We have listed some of the most common opioids here.
Morphine
You can take morphine as:
- short-acting tablets
- liquid that you swallow
- long-acting tablets or capsules
- a short-acting injection
- suppositories inserted into the back passage (rectum).
Morphine is known by different brand names. Short-acting preparations include Oramorph® and Sevredol®. Long-acting preparations include:
- Morphgesic SR®
- MST Continus®
- MXL®
- Zomorph®.
You usually take a short-acting type of morphine every 2 to 4 hours. This is usually as a tablet or a liquid. Your doctor or specialist nurse will tell you how often to take it. Liquid morphine has a bitter taste but mixing it with a fruit drink can help.
When the doctor knows how much morphine you need over 24 hours to control the pain, they usually change you to long-acting drugs. These drugs release the dose of morphine slowly over 12 or 24 hours. You may still need to take short-acting morphine in between if you get breakthrough pain.
Taking both long-acting and short-acting morphine gives you better control of the pain. This helps you to do the things you want without too many changes to your daily life.
You can also have morphine as an injection under the skin or through a syringe pump.
Oxycodone
If you cannot have morphine, or it is not working well for you, your doctor may prescribe oxycodone.
You can take oxycodone as:
- short-acting tablets, capsules, or liquid that you take every 4 to 6 hours
- long-acting tablets that you take every 12 hours
- an injection given under the skin or continuously through a syringe pump.
There are many different brand names of oxycodone. Short-acting preparations include Lynlor®, OxyNorm® and Shortec®.
Long-acting drugs include Ixyldone®, Longtec® and OxyContin®.
Fentanyl
You may have fentanyl once your doctor or nurse has worked out the dose of opioid you need.
Fentanyl patches
Fentanyl patches are waterproof plasters you stick on your skin. They release the drug at a constant rate through your skin. You change the patches every 3 days. You put the new patch on a different area of skin.
When you first use the patch, it takes around 12 to 24 hours for the fentanyl to reach the correct level in the blood. During this time, you usually need to take a short-acting opioid drug, to keep the pain under control.
If you are using fentanyl patches, it is important to:
- take the old patch off before applying a new one
- write the date on the patch when you apply it to remind you when to change it
- place patches on areas of dry, flat skin that have little or no hair
- stop the patch from getting hot by keeping it away from the sun, hot water, heat pads and hot water bottles
- let your doctor or nurse know if you have a temperature – this may affect how the medicine is absorbed through your skin
- tell your nurse if the patch causes a skin rash or itching
- dispose of your used patch carefully as some of the medication may still be left in the patch.
There are several different brands of fentanyl patches. They include Durogesic® and Victanyl®.
Other ways of taking fentanyl
You can take fentanyl by mouth, in several different ways. You put the following drugs between your cheek and gum:
- a short-acting lozenge - such as Actiq® or Cynril®
- a tablet - such as Effentora®
- a dissolvable film - such as Breakyl®.
You can also take fentanyl as a tablet you put under the tongue - such as Abstral®.
It is also available as a nasal spray - such as Instanyl® or PecFent®.
The drug is absorbed quickly into the body from your mouth or nose. Fentanyl given this way is usually for breakthrough pain.
Other opioid painkillers
Other opioids that are less commonly used include:
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Buprenorphine
This may be given as a:
- low dose skin patch you change every 7 days
- high dose skin patch you change every 3 to 4 days
- tablet you dissolve under the tongue every 6 to 8 hours.
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Diamorphine
Diamorphine is given as an injection. It is usually given continuously through a small needle under the skin connected to a syringe pump. Diamorphine changes into morphine in the body. You may have diamorphine if you are being sick, or if you find it difficult to swallow tablets or liquids.
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Tapentadol
Tapentadol (Palexia®) can be given as:
- short-acting tablets
- a short-acting liquid
- long-acting tablets.
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Methadone
Methadone (Physeptone®) may be given as:
- a tablet
- a liquid
- an injection, but this is rare.
Methadone is usually only given under close supervision from a specialist palliative care doctor or pain doctor.
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Alfentanil
Alfentanil (Rapifen®) is a strong painkiller that is given by injection or continuously through a syringe pump. It is more likely to be used if your kidneys are not working well.
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Side effects of painkillers
Some people get side effects from painkillers, especially opioids. But they will not affect everyone, and most side effects improve after a few days. We have explained some of the common side effects here.
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Drowsiness
Strong painkillers may make you feel drowsy when you first start taking them. This usually improves within a few days once you get used to the dose. If you are still feeling drowsy after a week, talk to your doctor or nurse. They can check the dose and if you are taking any other medicines that might cause drowsiness.
You should not drive when you start to take strong painkillers or if the dose has changed. This is because they may slow your reactions. Your body needs time to get used to the medication and dose.
If you feel drowsy, avoid driving or operating machinery. Alcohol can make drowsiness worse. It may be better to avoid it, or to only drink small amounts.
If you get drowsy after you have been taking strong painkillers for a while, tell your doctor or nurse. This sometimes happens if you have had treatments to shrink the cancer, which has helped to reduce the pain.
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Constipation
Constipation is a common side effect of strong painkillers. Your doctor usually prescribes you some laxatives. There are different types of laxatives. Some soften stools (poo) and make them easier to pass. Others stimulate the bowel to push the stools along more quickly. You may need a combination of laxatives to prevent constipation.
Do not take any laxatives without checking with your doctor, nurse or pharmacist first.
To help prevent constipation:
- try to drink plenty of fluids
- eat more high-fibre foods such as wholegrain bread, cereal, fresh fruit, dates, dried apricots, raisins, prunes, prune juice and nuts
- avoid or reduce foods that make you constipated
- try to do some gentle exercise if possible.
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Feeling sick (nausea)
Some people feel sick for a few days when they start taking painkillers. Some people may occasionally be sick (vomit). This usually gets better within a week. Your doctor may prescribe an anti-sickness (anti-emetic) drug for at least the first week of treatment. If it does not improve, tell your doctor. They may need to change your painkiller or the anti-sickness medicine.
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Dry mouth
Strong painkillers can make your mouth dry. If this happens, tell your doctor, nurse or pharmacist. There are different things that can help:
- taking regular sips of water
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sucking ice cubes or lollies
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chewing sugar-free gum
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using an artificial saliva product
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keeping food moist by adding sauces and gravies.
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Other side effects
Some people have other side effects with painkillers. These include:
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feeling forgetful or confused
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vivid dreams and hallucinations (seeing things that are not real)
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feeling dizzy or faint
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lower blood pressure
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slower, or sometimes deeper breathing.
If you have any of these, or any other side effects, tell your doctor straight away. They can change your dose of painkiller or give you another type. Some strong painkillers may suit you better than others.
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Other drugs used to control pain
There are other drugs that can be used to treat pain. You might take these with painkillers or on their own. The drugs your doctor prescribes will depend on the type of pain you have. Sometimes it can take some time to find the drug and dose that works best for you.
Your doctor or nurse will explain the different side effects of any drugs you are prescribed and how they may affect you.
Drugs to treat nerve (neuropathic) pain
Specific drugs are used to treat nerve pain. They are taken as tablets or capsules. It may take a few weeks for them to work. It is important to keep taking the drug your doctor prescribes, even if does not work straight away. The dose of the drug may need to be gradually increased.
Some of these drugs are also used to treat seizures. They change the way in which nerves send messages to your brain. They include:
- gabapentin
- pregabalin.
Other drugs that treat nerve pain can also be used in higher doses to treat depression. Some people worry about taking them because of this. But research shows that in lower doses they work well in targeting and reducing nerve pain. These drugs include:
- duloxetine
- amitriptyline
- clonazepam.
Drugs to treat bone pain
Specific drugs are used to treat bone pain. You have them as a drip into a vein, an injection or as tablets.
Bisphosphonates
People who have pain from cancer that has spread to the bones may be prescribed drugs called bisphosphonates. As well as helping to reduce pain, bisphosphonates also strengthen the affected bones. You have them as a drip into a vein or as tablets. Commonly used bisphosphonates are:
- sodium clodronate
- ibandronic acid
- disodium pamidronate
- zoledronic acid.
If you have a bisphosphonate as an injection into a vein, you have treatment once every 4 weeks.
Denosumab
Denosumab is treatment that can be used to relieve bone pain. You have it as an injection just under the skin, every 4 weeks.
Steroids to reduce swelling
Steroids can reduce swelling and pain caused by a tumour pressing on a part of the body. You usually have steroids as tablets, but they can also be given as an injection. There are different types. People usually have dexamethasone or prednisolone.
Drugs to relax muscles
If muscle spasms are causing pain, your doctor may prescribe a short course of a muscle relaxant such as:
- diazepam
- clonazepam
- baclofen (Lioresal®)
- hyoscine butylbromide (Buscopan®), which relaxes muscles in the bowel and helps treat tummy cramps.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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ReferencesBelow is a sample of the sources used in our cancer pain information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
ESMO Management of Cancer Pain in Adult Patients. ESMO Clinical Practice Guidelines. 2018. Available from: www.esmo.org/guidelines/esmo-clinical-practice-guideline-cancer-pain [accessed 24/03/2025].
NICE Palliative cancer care: Pain. 2025. Available from: cks.nice.org.uk/topics/palliative-cancer-care-pain/management/managing-pain-non-emergency/#management-of-breakthrough-pain [accessed 17/02/2025].
Scottish Palliative Care Guidelines. Available from: https://rightdecisions.scot.nhs.uk/scottish-palliative-care-guidelines/ [accessed 17/02/2025].
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