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Diamorphine is prescribed to treat severe pain.

It will be given to you by a doctor or nurse as an injection.

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

Type of medicineStrong opioid painkiller
Used forSevere pain
Also calledHeroin
Available asTablets and injection

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, although 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 way you feel pain.

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.

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 breast-feeding.
  • 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.
  • 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, such as herbal and complementary medicines.
  • Diamorphine is given as an injection. Your nurse or doctor will usually administer it for you. It can be given under the surface of your skin, into a muscle, or into your bloodstream. You may be given a repeat injection every four hours in order to control your pain.
  • Ask to read the manufacturer's printed information leaflet - 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 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.
  • Diamorphine is classed as a 'controlled drug' and is subject to certain restrictions. If you are planning a trip abroad and need to take a supply with you, you must speak with your doctor for advice before you travel.

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.

Common diamorphine side-effectsWhat can I do if I experience this?
Feeling dizzy, sleepy or drowsy, blurred visionDo not drive or use tools or machines. Do not drink alcohol
Feeling or being sickStick to simple meals - avoid rich or spicy foods. Your doctor may prescribe a medicine to ease the sickness
ConstipationEat a well-balanced diet and drink plenty of water each day. If this continues to be a problem, speak with your doctor
Dry mouthTry chewing sugar-free gum or sucking sugar-free sweets
Other side-effects include: sweating, feeling confused, difficulties passing urine, flushing, palpitations, mood changes, reduced appetite, rash, and itchingIf 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.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

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.

Further reading & references

  • Manufacturer's PIL, Diamorphine Hydrochloride Injection BP 5-10-30 mg, Actavis UK Ltd, electronic Medicines Compendium
  • British National Formulary; 66th Edition (September 2013) British Medical Association and Royal Pharmaceutical Society of Great Britain, London

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
3384 (v24)
Last Checked:
Next Review:
The Information Standard - certified member

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