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Diamorphine for pain relief

Diamorphine is prescribed to treat severe pain.

It will usually be given to you by a doctor or nurse as an injection. A nasal spray may sometimes be used for children in hospital.

The most common side-effects are constipation, drowsiness and feeling sick (nausea). Your doctor may prescribe medicines for you to take with diamorphine to help with some of these unwanted effects.

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About diamorphine

Type of medicine

Strong opioid painkiller

Used for

Severe pain

Also called

Diacetylmorphine (in US)

Available as

Injection, tablets and nasal spray

Strong opioids (sometimes called opiates) are medicines used to treat severe pain. Diamorphine is a type of strong opioid. It is used in particular to treat pain after a surgical operation and pain caused by cancer. It may also be used following a heart attack, or for breathlessness caused by fluid in the lungs. It works on your nervous system and brain to reduce the amount of pain you feel.

Diamorphine is usually given as an injection. Tablets of diamorphine are available but rarely prescribed. This is because other strong opioids (such as morphine) are preferred as they are absorbed better by your body when taken by mouth.

A nasal spray is available to treat severe pain in children. It is only given by a doctor or nurse in an emergency in hospital. A nasal spray is used because it is quicker to set up and less distressing for the child than an injection.

Before having diamorphine

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have heart, liver, or kidney problems.

  • If you have prostate problems or any difficulties passing urine.

  • If you have any breathing problems, such as asthma or chronic obstructive pulmonary disease (COPD).

  • If you have been told you have low blood pressure (hypotension).

  • If you have any problems with your thyroid or adrenal glands.

  • If you have epilepsy.

  • If you have a problem with your bile duct.

  • If you have severe diarrhoea, or have been constipated for more than a week, or have an inflammatory bowel problem.

  • If you have a condition causing muscle weakness, called myasthenia gravis.

  • If you have recently had a severe head injury.

  • If you have ever had a mental health problem called psychosis.

  • If you have ever been dependent on drugs or alcohol.

  • If you have ever had an allergic reaction to a medicine.

  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

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How diamorphine is given

  • Diamorphine is given as an injection into a muscle or into your bloodstream. Your nurse or doctor will usually administer it for you. You may be given a repeat injection every four hours in order to control your pain.

  • Diamorphine can also be given as an injection under the surface of your skin. Often this is done using a device known as a 'syringe driver' and a needle that stays attached to your skin. A syringe driver allows you to give yourself a dose of diamorphine without a nurse needing to inject it for you. This means that you can control your own pain relief by having a dose as soon as you feel it is needed. A syringe driver will only allow a certain number of doses to be given over a 24-hour period.

  • If your child is in hospital and in severe pain, the doctor may decide to use a diamorphine nasal spray. The spray gives effective pain relief and is often suitable for emergency situations. The number of sprays used will depend on the weight of your child.

Getting the most from your treatment

  • Ask to read the manufacturer's printed information leaflet for the product you (or your child) have been given - this will give you more information about diamorphine and a full list of the side-effects which you may experience from having it.

  • Ask your doctor for advice before drinking alcohol. Your doctor may recommend you do not drink alcohol while you are on diamorphine because it increases the chance of side-effects such as feeling dizzy and sleepy.

  • If you are a driver, please be aware that diamorphine is likely to affect your reactions and ability to drive. It is an offence to drive while your reactions are impaired. Even if your driving ability is not impaired, should you drive, you are advised to carry with you some evidence that the medicine has been prescribed for you - a repeat prescription form or a patient information leaflet from the pack is generally considered suitable.

  • If you are planning a trip abroad and need to take a supply with you, you are advised to carry a letter from your doctor to explain that you have been prescribed diamorphine. This is because diamorphine is classed as a 'controlled drug' and is subject to certain restrictions.

  • If you take or buy any 'over-the-counter' medicines, check with a pharmacist that they are suitable for you to take with diamorphine. Many other medicines have similar side-effects to diamorphine and taking them together will increase the risk of unwanted effects.

  • Before having any other medical treatment, tell the person carrying out the treatment that you are having diamorphine as a painkiller.

  • You will not be prescribed diamorphine for longer than necessary. This is because having diamorphine regularly for a long time can lead to your body becoming dependent on it, which might cause you to feel restless and irritable when it is then stopped. If you are concerned about this, discuss it with your doctor or pharmacist.

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Can diamorphine cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with diamorphine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.


diamorphine side-effects

What can I do if I experience this?

Feeling dizzy, sleepy or drowsy, blurred vision

Do not drive and do not use tools or machines. Do not drink alcohol

Feeling sick (nausea) or being sick (vomiting)

Stick to simple meals - avoid rich or spicy foods. Your doctor may prescribe a medicine to ease the sickness


Eat a well-balanced diet and drink plenty of water each day. If this continues to be a problem, speak with your doctor

Dry mouth

Take frequent sips of water. Try chewing sugar-free gum or sucking sugar-free sweets

Other side-effects of diamorphine include: sweating, feeling confused, difficulties passing urine, flushing, the sensation of having a 'thumping heart' (palpitations), mood changes, reduced appetite, rash, and itching

If any of these become troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

If you are caring for someone who has recently been given a dose of diamorphine and you notice the following side-effects, alert a doctor or nurse as soon as possible:

  • Very small, 'pinpoint' pupils (the black circle of the eye).

  • Shallow breathing or difficulty breathing.

  • Losing consciousness (falling asleep).

  • Having a fit (seizures or convulsions).

How to store diamorphine

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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