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 back passage (anus). Morphine injections are usually only done in hospital.

• 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.
• Morphine is also called by the brand names MST, Zomorph, Sevredol, Morphgesic, MXL or Oramorph.

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:

• had an allergic reaction to morphine or any other medicines in the past
• breathing difficulties
• a lung problem
• an addiction to alcohol
• an illness which causes seizures
• a head injury
• low thyroid levels
• adrenal gland problems
• kidney or liver problems
• an enlarged prostate
• low blood pressure
• myasthenia gravis (a rare illness that causes muscle weakness)

Morphine is generally not recommended in pregnancy. Tell your doctor before taking morphine if you're trying to get pregnant, are already pregnant or if you're breastfeeding.

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 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 can't 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

How much to take

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.

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 isn't 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 don't get unpleasant withdrawal symptoms.

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

• feeling agitated
• feeling anxious
• shaking
• sweating

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

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.

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.

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 don't go away:

• constipation
• feeling or being sick (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 (seizures)

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

Serious allergic reaction

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

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

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 (vomiting) - 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 don't 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.

Morphine is generally not recommended during pregnancy and while breastfeeding.

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.

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

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.

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 can't 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
• 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.