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Morphine - Brand names: MST, Zomorph, Sevredol, Morphgesic, MXL, Oramorph

On this page

  1. About morphine
  2. Key facts
  3. Who can and cannot take morphine
  4. How and when to take it
  5. Taking morphine with other painkillers
  6. Side effects
  7. How to cope with side effects of morphine
  8. Pregnancy and breastfeeding
  9. Cautions with other medicines
  10. Common questions about morphine

1. About morphine

Morphine is a strong painkiller. It's used to treat severe pain, for example after an operation or a serious injury, or pain from cancer or a heart attack.

It's also used for other types of long-standing pain when weaker painkillers no longer work.

Morphine is available only on prescription. It comes as tablets, capsules, granules that you dissolve in water, a liquid to swallow, an injection or a suppository which is a medicine that you push gently into your bottom (anus). Morphine injections are usually only done in hospital.

2. Key facts

  • Morphine works by blocking pain signals from travelling along the nerves to the brain.
  • The most common side effects of morphine are constipation, feeling sick and sleepiness.
  • It's possible to become addicted to morphine, but this is rare if you're taking it to relieve pain and your doctor is reviewing your treatment regularly.
  • It may be best not to drink alcohol while taking morphine as you're more likely to get side effects like feeling sleepy.

3. Who can and cannot take morphine

Morphine can be taken by children and adults of all ages. However babies, young children and older people are more likely to get side effects.

Morphine is not suitable for some people. Tell your doctor before starting the medicine if you:

  • have ever had an allergic reaction to morphine or any other medicine
  • have breathing difficulties or a lung problem
  • have an addiction to alcohol
  • have a condition that causes fits or seizures
  • have a head injury
  • have low thyroid levels
  • have adrenal gland problems
  • have kidney or liver problems
  • have an enlarged prostate
  • have low blood pressure
  • have myasthenia gravis (a rare illness that causes muscle weakness)
  • are trying to get pregnant, are already pregnant or if you're breastfeeding – morphine is usually not recommended

4. How and when to take it

It's important to take morphine as your doctor has asked you to.

Take morphine with, or just after, a meal or snack so it's less likely to make you feel sick.

Different types of morphine

Morphine comes as:

  • tablets (fast-acting) – these contain 10mg, 20mg or 50mg of morphine
  • tablets (slow-acting) – these contain 5mg, 10mg, 15mg, 30mg, 60mg, 100mg or 200mg of morphine
  • capsules (slow-acting) – these contain 10mg, 30mg, 60mg, 90mg, 120mg, 150mg or 200mg of morphine
  • granules (that you mix in water to make a drink) – these are in sachets containing 30mg, 60mg, 100mg or 200mg of morphine
  • a liquid that you swallow – this contains either 10mg of morphine in a 5ml spoonful or 20mg of morphine in 1ml of liquid
  • suppositories – these contain 10mg of morphine
  • injection (usually given in hospital)

Morphine suppositories are useful if you cannot swallow tablets or liquids.

Morphine liquid, suppositories, injections and some morphine tablets and capsules are fast acting. They're used for pain which is expected to last for a short time. Fast-acting morphine is often used when you start taking morphine to help find the right dose.

Morphine granules and some morphine tablets and capsules are slow release. This means the morphine is gradually released into your body over either 12 or 24 hours. This type of morphine takes longer to start working but lasts longer. It's used for long-term pain.

Sometimes you may take both a fast-acting morphine and a slow-release morphine to manage long term pain and sudden flares of pain that break through the long-acting medicine.

Fast-acting tablets are known by the brand name Sevredol. Slow acting tablets are known by brand names MST Continus or Morphgesic SR. Slow acting capsules are also known as MXL or Zomorph.

Morphine does not come as a skin patch. Sometimes people call their pain relief patch a "morphine patch". However these patches do not contain morphine but medicines which are very similar to morphine called fentanyl or buprenorphine.


Doses vary from person to person. Your dose will depend on how bad your pain is, how you've responded to previous painkillers and if you get any side effects.

How often will I take it?

How often you take it depends on the type of morphine that you've been prescribed.

You can choose to take your morphine at any time of day but try to take it at the same time every day and space your doses evenly. For example, if you take morphine twice a day and have your first dose at 8am, take your second dose at 8pm.

  • fast-acting tablets and capsules – usually 4 to 6 times a day
  • slow-release granules, tablets and capsules – usually 1 to 2 times a day
  • liquid – usually 4 to 6 times a day
  • suppositories – usually 4 to 6 times a day
  • injections – usually 4 to 6 times a day (sometimes in a pump that you control yourself)

It's important to swallow slow-release morphine tablets and capsules whole with a drink of water.


Do not break, crush, chew or suck morphine slow-release tablets or capsules. If you do, the slow-release system will not work and the whole dose might get into your body in one go. This could cause a potentially fatal overdose.

Will my dose go up or down?

Usually, you start on a low dose of morphine and this is increased slowly until your pain is well controlled. Once your pain is under control, talk to your doctor about swapping to slow-release morphine. This may cut down the number of doses you have to take each day.

When you stop taking morphine your dose will go down gradually, especially if you've been taking it for a long time.

How long will I take it for?

Depending on why you're taking morphine, you may only need to take it for a short time. For example, if you're in pain after an injury or operation, you may only need to take morphine for a few days or weeks at most. You may need to take it for longer if you have a long-term condition such as back pain.

What if I forget to take it?

This will vary depending on which type of morphine you're taking.

If you forget to take a dose, check the information on the patient information leaflet inside the packaging or ask your pharmacist or doctor for advice on what to do.

Never take 2 doses at the same time to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember to take your medicine.

What will happen if I stop taking it?

If you need to take morphine for a long time your body can become tolerant to it.

This is not usually a problem but you could get unpleasant withdrawal symptoms if you stop taking it suddenly.

If you want to stop taking morphine, talk to your doctor first. Your dose can be reduced gradually so you do not get unpleasant withdrawal symptoms.

If you stop taking morphine suddenly it can cause unpleasant withdrawal symptoms such as:

  • feeling agitated
  • feeling anxious
  • shaking
  • sweating


If you have been taking morphine for more than a few weeks do not stop taking it without speaking to your doctor first.

What if I take too much?

Taking too much morphine can be dangerous.

If you've taken an accidental overdose you may feel very sleepy, sick or dizzy. You may also find it difficult to breathe. In serious cases you can become unconscious and may need emergency treatment in hospital.

The amount of morphine that can lead to an overdose varies from person to person.

Urgent advice: Contact 111 for advice now if:

  • you or a child have taken too much morphine

Go to or call 111

If you need advice for a child under the age of 5 years, call 111.

If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.

Take the morphine box or leaflet inside the packet plus any remaining medicine with you.

Where to store morphine

If you're prescribed morphine, it's particularly important that you:

  • store it properly and safely at home
  • keep it out of the sight and reach of children
  • never give your medicine to anyone else

Return any unused morphine to your pharmacist who will dispose of it.

5. Taking morphine with other painkillers

It's safe to take morphine with paracetamol, ibuprofen or aspirin.

Do not take codeine-containing painkillers that you can buy alongside prescribed morphine (and prescribed codeine). You will be more likely to get side effects.

Some everyday painkillers that you can buy without prescription from pharmacies contain codeine, which is a similar medicine to morphine. Codeine-containing painkillers from pharmacies include co-codamol, Nurofen Plus and Solpadeine.

6. Side effects

Like all medicines, morphine can cause side effects in some people but many people have no side effects or only minor ones.

The higher the dose of morphine the more chance that you will get side effects.

Common side effects

Common side effects happen in more than 1 in 100 people. Talk to your doctor or pharmacist if the side effects bother you or do not go away:

  • constipation
  • feeling or being sick (nausea or vomiting)
  • feeling sleepy or tired
  • dizziness and a sensation of spinning (vertigo)
  • confusion
  • headaches
  • itchiness or rash

Serious side effects

Serious side effects happen in less than 1 in 100 people. Call your doctor if you get:

  • breathing difficulty or short shallow breathing
  • muscle stiffness
  • feel dizzy, tired and have low energy – this could be a sign of low blood pressure
  • fits or seizures

If you have a fit or seizure go to A&E straight away.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to morphine.

Immediate action required: Call 999 or go to A&E if:
  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of morphine. For a full list see the leaflet inside your medicines packet.


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

7. How to cope with side effects of morphine

What to do about:

  • constipation – try to eat more high-fibre foods such as fresh fruit and vegetables and cereals. Try to drink several glasses of water or other non-alcoholic liquid each day. If you can, it may also help to do some gentle exercise. Speak to your doctor about medicine to help prevent or treat constipation caused by morphine if your symptoms do not go away.
  • feeling or being sick – take morphine with or just after a meal or snack to ease feelings of sickness. This side effect should normally wear off after a few days. Talk to your doctor about taking anti-sickness medicine if it carries on for longer.
  • feeling sleepy, tired or dizzy – these side effects should wear off within a week or two as your body gets used to morphine. Talk to your doctor if they carry on for longer.
  • confusion – talk to your doctor if you feel confused, your dose may need to be adjusted.
  • headaches – make sure you rest and drink plenty of fluids. It may be best not to drink alcohol while taking morphine as this can make headaches worse. Ask your pharmacist to recommend a painkiller. Headaches should usually go away after the first week of taking morphine. Talk to your doctor if they last longer than a week or are severe.
  • itchiness or rash – it may help to take an antihistamine which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you. If symptoms do not go away or get worse talk to your doctor as you may need to try a different painkiller.

Do not take any other medicines to treat the side effects of morphine without speaking to your pharmacist or doctor.

8. Pregnancy and breastfeeding

Morphine is generally not recommended during pregnancy and while breastfeeding.

Morphine and pregnancy

In early pregnancy, it's been linked to some problems for your unborn baby. If you take morphine at the end of pregnancy there's a risk that your newborn baby may get withdrawal symptoms or be born addicted to morphine.

However, it's important to treat pain in pregnancy. For some pregnant women with severe pain, morphine might be the best option. Your doctor is the best person to help you decide what's right for you and your baby.

Morphine and breastfeeding

Morphine is not usually recommended if you're breastfeeding. Small amounts of morphine pass into breast milk and can cause breathing problems in the baby. Speak to your doctor as they may be able to recommend a different painkiller.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

For more information about how morphine can affect you and your baby during pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPs) website.

9. Cautions with other medicines

Some medicines and morphine interfere with each other and increase the chance that you will have side effects.

Tell your doctor if you are taking any medicines:

  • to help you sleep
  • for depression – some types cannot be taken with morphine
  • for high blood pressure
  • to help stop you feeling or being sick (vomiting)
  • to treat symptoms of an allergy
  • to reduce tension or anxiety
  • for mental health problems

Mixing morphine with herbal remedies and supplements

It's not possible to say that complementary medicines are safe to take with morphine. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

Important: Medicine safety

Tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

10. Common questions about morphine

How does morphine work?

Morphine is from a group of medicines called opiates, or narcotics.

It works in the central nervous system and the brain to block pain signals to the rest of the body. It also reduces the anxiety and stress caused by pain.

When morphine blocks the pain, there are other unwanted effects, for example, slow or shallow breathing. It also slows down digestion, which is why morphine can cause constipation.

How long will it take to work?

This depends on the type of morphine you take.

A morphine injection into a vein gives the quickest pain relief. It works almost straight away.

Fast-acting morphine taken by mouth works in 30 to 60 minutes but it wears off after 4 to 6 hours. Slow-acting morphine taken by mouth can take a day or 2 to start working but the pain relief will last for longer.

It's difficult to say how long morphine suppositories take to work, as it varies from person to person.

Can I become addicted to morphine?

Yes, morphine is addictive. If you need to take it for a long time your body can become tolerant to it. That means you need higher doses to control your pain.

But in reality, if you're taking morphine to relieve pain (rather than using it as a recreational drug) it's very unlikely you will get addicted to it because you're not taking it to get a "high".

How will I know if I'm addicted?

If you're addicted to morphine, you may find it difficult to stop taking it or feel you need to take it more often than necessary.

And if you stop taking morphine suddenly you may suffer from withdrawal symptoms. These include agitation, anxiety, nervousness, panic attacks, difficulty sleeping, shaking, over-activity, pins and needles or ringing in the ears.

Talk to your doctor if you're worried about addiction or if you want to know more about how to prevent withdrawal symptoms.

Is morphine a controlled medicine?

Morphine is a controlled medicine. This means there are strict rules on how it's prescribed and dispensed to make sure it's not given to the wrong person or misused.

When you collect morphine your pharmacist will ask for proof of your identity such as your passport or driving licence. You'll also be asked to sign the back of your prescription, to confirm that you've received it.

If you're collecting morphine for someone else, you're legally required to show the pharmacist proof of your identity if asked.

How can I tell if I am taking slow or fast release morphine?

Fast-acting morphine tablets are also known as Sevredol. Slow-acting tablets are also known as MST Continus or Morphgesic SR. Slow-acting capsules are also known as MXL or Zomorph.

Will it affect my fertility?

There's no clear evidence to suggest that taking morphine will reduce fertility in men.

However, it may interfere with your periods (menstrual cycle) if you're a woman. Speak to a pharmacist or your doctor if you're trying to get pregnant. They may want to review your treatment.

Will it affect my contraception?

Morphine does not affect any type of contraception including the contraceptive pill or emergency contraception.

But if morphine makes you sick (vomit), your contraceptive pills may not protect you from pregnancy.

If this happens, follow the instructions in the leaflet that comes with your contraceptive pills.

Find out what to do if you're on the pill and you're sick.

Can I drink alcohol with it?

It may be best not to drink alcohol while taking morphine as drinking alcohol while you're on morphine may make you feel more sleepy or increase the risk of serious side effects.

It's best to stop drinking alcohol during the first few days of treatment until you see how the morphine affects you.

If you feel sleepy with morphine, stop drinking alcohol while you are taking it.

Are there other painkillers I can try?

The type of painkiller that's best depends on what type of pain you have and the cause of your pain. If morphine does not get rid of your pain or becomes less effective, discuss this with your doctor.

Will it make me so sleepy I cannot function?

When you first take morphine, you'll probably feel sleepy for a few days. But the sleepiness will wear off after a few days as your body gets used to the medicine.

You might notice you are less alert. In this case, you might choose to have less than perfect pain relief as a trade-off.

Is morphine only used at the end of life?

Morphine is not only used at the end of a terminal illness. It's the amount of pain you have, not the stage of your illness, that decides whether morphine is prescribed for you.

Can children take morphine?

Morphine can be used safely in babies and children of all ages, although the dose is usually lower than for adults.

Can I drive or ride a bike?

Do not drive a car or ride a bike if morphine makes you sleepy, gives you blurred vision or makes you feel dizzy, clumsy or unable to concentrate or make decisions. This may be more likely when you first start taking morphine but could happen at any time, for example, when starting another medicine.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

It may be best not to drink alcohol while taking morphine as you're more likely to get side effects like feeling sleepy.

Even if your ability to drive is not affected, the police have the right to request a saliva sample to check how much morphine is in your body. GOV.UK has more information on the law on drugs and driving.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking morphine.

Will recreational drugs affect it?

If you take recreational drugs, such as cannabis, cocaine and heroin, while you're taking morphine, you're more likely to get the serious side effects of morphine including breathing difficulties, heart problems such as high blood pressure, seizures and even going into a coma.

Some recreational drugs, such as cannabis, will also increase morphine side effects such as sleepiness and dizziness.

Taking heroin while you're on prescribed morphine is especially dangerous. You're more likely to get all the side effects of morphine, including addiction.

Tell your doctor if you think you may take recreational drugs while you're on morphine.

Related conditions

Page last reviewed: 23 November 2018
Next review due: 23 November 2021