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Read about diamorphine, how you have it and other important information about taking this painkiller.

Diamorphine is a pain killing drug. You have it for moderate to severe pain. It can also reduce breathlessness caused by a build up of fluid around the lung (a pleural effusion). 

You can only get diamorphine on prescription from your doctor. It is a type of opioid.

How it works

Diamorphine works by acting like the body’s natural painkillers known as endorphins. These control pain by blocking pain messages to the brain.

How you have it

You can have diamorphine in a number of different ways. You might have it as injection into your vein, or an injection just under your skin, or an injection into the muscle. Or you might have diamorphine as tablets.

The dose you have depends on the level of your pain and the amount needed to control it. Your doctor or nurse will give you instructions on how much diamorphine to have and when to have it.

An injection into your vein (intravenous injection)

You might have diamorphine 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. 

An injection under the skin (subcutaneous injection)

You can have diamorphine as an injection into the fatty tissue just under the skin. This might be in your thigh, stomach or upper arm 

Some people have diamorphine into the fatty tissue through a small needle put just under the skin and connected to a pump called a syringe driver. The pump gives you a small amount of diamorphine continuously. A nurse changes the pump every 24 to 48 hours. Or the nurse may teach you or your carer how to do this.

An injection into your muscle

Some people have diamorphine as an injection into the muscle (intramuscularly), but this is not common. You usually have it in your buttocks or upper thigh. 

You usually have intraveous, subcutaneous or intramuscular injections every 4 hours, unless you have it as part of a syringe driver.


You swallow the tablets with plenty of water. You usually take them every 4 hours.

You must take tablets and capsules according to the instructions your doctor or pharmacist gives you.

You should take the right dose, not more or less.

Never stop taking a cancer drug without talking to your specialist first.

Tests during treatment

You have blood tests before starting treatment and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Side effects

Important information

Other medicines, foods and drink

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.

Pregnancy and contraception

It is important not to become pregnant while having diamorphine. There is a risk that the baby could become dependent on it and suffer from withdrawl symptoms after the birth.

Talk to your doctor or nurse about effective contraception.


Don't breastfeed while having diamorphine because the drug may come through in the 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.

Addiction and diamorphine

Some people worry about becoming addicted to diamorphine. When you take this kind of drug to control pain, it is unlikely that you will become addicted. But talk to your doctor or specialist nurse if you are worried. 

Drowsiness and diamorphine

If you become drowsy after having diamorphine for a while, it may mean that you need to lower your dose. Talk to your doctor or nurse before you change your dose. It is important to let them know. It can be very harmful to just stop taking diamorphine. You are likely to need to slowly reduce the amount you take.

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.

Information and help

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