Morphine is a type of painkiller. You can only get it on prescription from your doctor and you have it for moderate to severe pain.

Morphine is also called:

  • Morphgesic SR
  • MXL
  • Zomorph
  • MST
  • Sevredol
  • Oramorph

How morphine works

Morphine is a type of opioid. Opioids are strong drugs similar to natural pain killing substances made in our body called endorphins. It is extracted from opium poppies in a laboratory.

Opioids block pain messages from travelling along the nerves to the brain. 

How you have it

Morphine is available in different forms such as:

  • tablets or capsules
  • liquids
  • injections
  • suppositories

Morphine tablets or capsules

Many people take morphine as tablets or capsules. You take them with a glass of water, with or without food. 

There are different types and doses of morphine. They come in different colours to help you tell the doses apart. There are also different brands of morphine. Common types include Sevredol and Oromorph (short acting) or MST Continus and MXL (long acting).

Short acting morphine

Short acting morphine lasts for 2 to 4 hours per dose. Most people start on a short acting morphine tablet or liquid. This is because it is easier and quicker to adjust the dose. 

Once your pain is under control, you might change to a long acting (or slow release) tablet or capsule.

Long acting morphine

Long acting morphine lasts from 12 to 24 hours per dose. You take it either once or twice a day. 

If you are taking it twice a day, you should take it in the morning and at night, for example at 8am and 8pm. 

It is important that you take morphine regularly, even if you don't feel pain. The slow release tablets or capsules can take up to 48 hours to give you a steady dose. So if you stop and start, they won't work so well. 

Liquid morphine

Liquid morphine comes as a syrup or as a powder that you dissolve in water. 

There are different brands of liquid morphine such as Oramorph (short acting) and MST Continus suspension (long acting powder for dissolving in water). 

Morphine injections

When you can't swallow or are feeling sick, you can have morphine as an injection. There are different ways of having morphine injections such as under the skin (subcutaneous), into a muscle (intramuscular) or into a vein (intravenous). 

Injection under the skin (subcutaneous injection)

You may have morphine injections under the skin into your: 

  • stomach
  • thigh
  • upper arm

You might have stinging or a dull ache for a short time after this type of injection, but they don't usually hurt much. The skin in the injection site may also go red and itchy for a while. 

Some people have morphine under the skin continuously through a small needle connected to a pump called a syringe driver. It gives a continuous small volume of morphine. 

Your nurse will change the syringe driver every 24 or 48 hours. This way of having morphine is helpful for people who find it difficult to swallow.  

Injections into a vein (intravenously injection)

You can have morphine into your bloodstream. You usually have it through a thin, short tube (a cannula) put into a vein in your arm or the back of your hand. Or you may have it through a central line, a portacath or a PICC line.

These are long, plastic tubes that give the drug directly into a large vein in your chest.  

When you have morphine

Your doctor or specialist nurse will help you choose the type and dose that best controls your pain. It depends on the pain you have and the amount of drug you need to control it.

You may feel drowsy when you first start taking morphine or if the dose is increased. If the drowsiness lasts more than a couple of days talk to your doctor or nurse.

You shouldn't just stop taking morphine suddenly. It is likely that you need to slowly reduce the amount you take. Always talk to your doctor or specialist nurse before you change your dose.

Side effects

How often and how severe the side effects are can vary from person to person. They also depend on what other treatment you are having. For example, your side effects could be worse if you are also having other drugs or radiotherapy.

When to contact your team

Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 
  • your side effects aren’t getting any better
  • your side effects are getting worse
Early treatment can help manage side effects better.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:


Constipation is easier to sort out if you treat it early. Drink plenty of fluids and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your doctor or nurse if you are constipated for more than 3 days. They can prescribe a laxative.

Feeling sick

This is usually mild. Let your doctor or nurse know if you have it.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • feeling confused
  • difficulty sleeping
  • dizziness
  • headaches
  • sudden jerking of the body due to muscle contractions
  • extreme tiredness and weakness
  • extreme sweating
  • tummy (abdominal) pain
  • loss of appetite
  • dry mouth
  • rash or itchy skin
  • being sick – this should normally wear off after a few days and you can have tablets to help
  • generally feeling unwell

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • increased sensitivity to pain
  • allergic reaction which includes swelling of the mouth and face, difficulty breathing, dizziness and a skin reaction such as a rash or itching
  • feeling agitated
  • seeing or hearing things that are not there
  • mood changes including feeling very happy or confident
  • fits (seizures)
  • stiffness or sudden movements of the muscles
  • tingling or numbness in the skin
  • fainting
  • problems with your eyes such as blurred vision
  • feeling of failing or the room spinning (vertigo)
  • heart problems such as palpitations and high or low blood pressure
  • redness (flushing) of the face
  • bronchospasm which may cause pain or tightness in chest, difficulty breathing, feeling dizzy or tired for no reason and coughing
  • fluid build up in the lungs
  • slow and shallow breathing
  • changes in taste
  • indigestion
  • decreased bowel movement which can cause tummy pain
  • changes in enzyme levels in the liver
  • not being able to empty your bladder
  • swelling from a fluid up of fluid in the arms or legs

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Other medicines, foods and drinks

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Loss of fertility

It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Contraception and pregnancy

This treatment may harm a baby developing in your womb. It is important not to become pregnant while you are having treatment. Talk to your doctor or nurse about effective contraception before starting treatment.


Don’t breastfeed during this treatment because the drug may come through into your breast milk.

Treatment for other conditions

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.

Tolerance and addiction

People taking morphine for weeks or months can develop a physical dependence on the drug. This causes withdrawal symptoms if the drug is stopped. 

Your doctor or nurse will advise you how to reduce the morphine dose gradually if necessary. Don't stop taking morphine suddenly. 

Some people can also develop a psychological dependence (addiction) to morphine. This may be more likely in people who have problems with alcohol or drug use. 

Talk to your doctor or specialist nurse if you are worried about becoming addicted to morphine.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Last reviewed: 
21 May 2019
  • Electronic Medicines Compendium 
    Accessed May 2019

  • Management of cancer pain: ESMO Clinical Practice Guidelines
    CI Ripamonti and others
    Annals of Oncology, 2011. Volume 22, Supplement 6

  • Palliative care for adults: strong opioids for pain relief
    National Institute for Health and Care Excellence, 2012

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