Anaesthesia explained

Published: 01/03/2021

Pain relief

Good pain relief after your operation is important. As well as making you comfortable, it allows you to get active more quickly and reduces complications.

If you have good pain relief, you will be able to:

  • breathe deeply and cough, at least gently (which will help make sure you do not develop a chest infection after your operation); and
  • move about freely. Exactly how much and how soon you will move around the bed, or get out of bed, will depend on the operation you have had and your general state of health. Early movement helps prevent blood clots in your legs (deep-vein thrombosis or DVT). Getting out of bed helps you to expand your lungs and to avoid a chest infection. It also helps prevent stiff joints, an aching back and pressure sores where you have been lying.

Not everyone needs to see a physiotherapist for this type of care. Your doctors and nurses will ask for this kind of physiotherapy for you if they think it is needed.

Planning your pain relief

Your anaesthetist will talk with you before your operation about pain relief afterwards. You can discuss your preferences and decide together what pain relief you will have. They will prescribe some pain relief, and more will be available if you need it.

The amount and type of pain relief you need depends on the operation you are having. Some people need more pain relief than others.

  • Pain relief can be increased, given more often, or given in different combinations.
  • Most pain-relief treatments also have side effects. Your doctors will take these effects into consideration as they advise you on which type of pain relief is best for you.
  • Occasionally, pain is a warning sign that all is not well, so you should tell your nurses about any pain you experience.
  •  It is easier to keep pain under control if we treat it early, so let your nurse know as soon as possible if you think the pain is getting worse.

Ways of taking pain relief Your anaesthetist will be able to talk with you about which types of pain relief are appropriate for you.

Pills, tablets or liquids to swallow

Pills, tablets or liquids are used for all types of pain. They typically take 30 minutes to work and are best taken regularly. You need to be able to eat and drink without being sick for these drugs to work.

Injections into a muscle

These are not needed very often, but may be prescribed as an extra form of pain relief if you unexpectedly have a lot of pain. They may be given into your leg or buttock muscle and typically take 10–15 minutes to work.


These waxy pellets are placed in your rectum (back passage). The drug dissolves and is absorbed into the body, typically taking 20 minutes to work. They are useful if you cannot swallow or feel very sick.

Intravenous pain relief (into a vein)

During your anaesthetic and in the recovery room your anaesthetist and nurses may give you drugs into your blood through your cannula. This means they work more quickly than if the same drugs are given as a tablet or injection into a muscle.

Pain-relief drugs

Two basic types of pain-relief drug are given commonly.

  •  paracetamol
  •  anti-inflammatory medicines (for example, ibuprofen and diclofenac).

Each of these medicines can be given as a tablet or liquid to swallow, by an injection into a muscle or vein, or as a suppository. They can be used together as they belong to different drug types.

Anti-inflammatory drugs have a number of side effects which make them unsuitable for some people. Your anaesthetist will consider this before prescribing them for you.

Opiate pain-relief medicines

These drugs are used after operations that are expected to cause considerable pain.

Morphine, diamorphine, pethidine, codeine, tramadol and oxycodone are all opiate pain-relief medicines. They may be given as a tablet or liquid to swallow, as an injection into a muscle, or intravenously (your bloodstream) into your cannula.

Side effects are common with these drugs. These include feeling sick, vomiting, itching, drowsiness and, if used over a few days, constipation. Larger doses can cause very slow breathing and low blood pressure. The nursing staff will watch you closely for all of these side effects. If they happen, other treatments will be given to keep you safe.

Anti-sickness drugs will be given as well. One in three people find opiates unpleasant, but they are the most effective pain-relief medicines in many circumstances.

Other ways of giving pain relief

Patient-controlled analgesia (PCA)

This is a system which allows you to control your own pain relief. Opiate drugs (see above) are put into a pump which is connected to your cannula. The pump has a handset with a control button which you will be shown how to operate. When you press the button, a small dose of the opiate drug goes straight into your cannula.

Using a PCA allows you to help yourself to a small dose of pain relief very frequently. The anaesthetist sets the dose and also a minimum time limit between doses (usually five minutes). After that time has passed, you can decide whether you want another dose. The drug goes straight into a vein, so it works very quickly. You can continue to press the button at five-minute intervals until your pain is reduced to an acceptable level for you. You can then have further doses to top up your pain relief as you need them, to keep yourself comfortable.

Your nurses watch you carefully while you are using a PCA, to make sure that you are reacting safely to the pain-relief medicine.

There is evidence that patients benefit from being in control of their own pain relief. This type of pain relief is at least as safe, or safer, than other ways of giving opiate pain relief.

Local-anaesthetic catheters

These are fine tubes which the surgeon can place under the skin, near to your surgical wound or to the nerves that supply the area. Not all operations are suitable for having local-anaesthetic catheters.

Each catheter is attached to a pump that contains local anaesthetic. The local anaesthetic blocks pain signals from nearby nerves and should reduce your pain. The pump can be kept running for several days.

These catheters do not always relieve pain well, but there is evidence which shows that they are generally helpful, with few side effects.

An epidural catheter for pain relief

This is a system for pain relief for operations commonly on the lower body but also for some operations on the chest and upper abdomen.

A fine tube (epidural catheter) is placed into your back, using a needle. A pump is used to run local anaesthetic continuously into the epidural catheter. This makes the lower half of your body become numb. The numbness lasts as long as the catheter is in place and the pump is running. When the catheter is removed, feeling in the area gradually returns to normal.

An epidural can be used for pain relief for most major operations on the lower body. For more information, please see the leaflet Epidural pain relief after surgery.

Pain relief at home

Your anaesthetist or doctors and nurses on the ward (or both) will make a plan for your pain relief after discharge.

You may be asked about pain-relief drugs that you already have at home, such as paracetamol and ibuprofen. It is a good idea to stock up on pain-relief tablets before you come into hospital. Staff at the preoperative assessment clinic will be able to advise.

You should take tablets for pain relief regularly to best manage your pain. Regular use of these simple pain killers significantly reduces the amount of strong painkiller you will need (such as morphine or codeine) and the side effects associated with stronger drugs.

You may be advised to take several different types of pain relief. It is important that you understand how to use the different drugs and that you are aware of possible side effects. This will be explained to you. It is helpful if a relative or friend listens when this information is given, to help you remember what to do. Ideally you will receive written information as well.

You may go home on opioid-based pain killers following your operation. It is important that you reduce and then stop these medications as soon as possible, as their continued use can cause you significant harm. Your GP can help you in reducing these after surgery and you should seek their advice if you encounter difficulties. You should be fully advised on this before you leave hospital.

Who can give me advice when I am at home?

Before you leave the ward, you should make sure you know who to contact and how if you develop significant pain or other problems at home. You may get this information from:

  • the member of staff who arranges your discharge from hospital
  • the doctors on the ward, or
  • your surgeon or anaesthetist.

This is especially important if you go home on the day of your operation.