Codeine is a painkiller. It's used to treat pain, for example after an operation or an injury. It's also used for long-standing pain when everyday painkillers, such as aspirin, ibuprofen and paracetamol, haven't worked.

Codeine is also used to treat diarrhoea.

Codeine is available on prescription. It comes as tablets, a liquid to swallow and as an injection. Codeine injections are usually only given in hospital.

You can buy lower-strength codeine from a pharmacy. It comes mixed with paracetamol (co-codamol) or with aspirin (co-codaprin) or with ibuprofen (Nurofen Plus).

You can also buy codeine from a pharmacy as a syrup (linctus) to treat dry coughs.

• Codeine works by stopping pain signals from travelling along the nerves to the brain.
• The most common side effects of codeine are constipation, feeling sick (nausea) and feeling sleepy.
• It's possible to become addicted to codeine, 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 codeine as you're more likely to get side effects like feeling sleepy.
• Do not give codeine to children under 12 years old. Only give codeine to children aged 12 to 18 years if everyday painkillers like paracetamol and ibuprofen haven't worked.

Codeine can be taken by adults and children aged 12 years and older.

Only give codeine to children (aged 12 to 18 years) if everyday painkillers such as paracetamol and ibuprofen haven't worked.

Codeine is not suitable for some people. Tell your doctor before starting the medicine if you have:

• had an allergic reaction to codeine or any other medicines in the past
• a lung problem
• a head injury
• adrenal gland problems
• an illness which causes seizures
• an addiction to alcohol
• an underactive thyroid gland
• kidney or liver problems
• gallstones
• an enlarged prostate
• low blood pressure
• myasthenia gravis (a rare illness that causes muscle weakness)
• symptoms of ulcerative colitis (a bowel condition)

Do not give codeine to children who are under 18 years old and have had their tonsils or adenoids removed because of a sleep problem called obstructive sleep apnoea.

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

It's important to take codeine as your doctor has asked you to.

Take codeine with, or just after, a meal or snack so it's less likely to make you feel sick.

You can take codeine at any time of day but try to take it at the same times every day and space your doses evenly.

Different types of codeine

Codeine comes as:

• tablets - these contain 15mg, 30mg or 60mg of codeine
• a liquid that you swallow - this contains 25mg of codeine in a 5ml spoonful
• cough syrup - this contains 15mg of codeine in a 5ml spoonful
• an injection (usually given in hospital)

If you're taking codeine as a liquid, it will come with a plastic spoon or syringe to help you measure the correct amount. Ask your pharmacist for one if you don't have it. Do not measure the liquid with a kitchen teaspoon because it won't give the right amount.

How much to take

The usual dose of codeine is 15mg to 60mg. You can take this dose up to 4 times a day.

For treating pain:

• adults usually take one or two 30mg tablets every 4 hours
• children (aged 12 to 18 years) usually take one or two 30mg tablets (or one or two 5ml spoonfuls of liquid) every 6 hours
• elderly people or people with kidney or liver problems usually take a 15mg tablet every 4 hours

For treating diarrhoea:

• adults usually take one or two 30mg tablets (or one or two 5ml spoonfuls of liquid) every 4 hours
• children (aged 12 to 18 years) usually take one or two 30mg tablets (or one or two 5ml spoonfuls of liquid) every 6 hours
• elderly people or people with kidney or liver problems usually take a 15mg tablet every 4 hours

For treating a cough: Adults and children usually take one or two 5ml spoonfuls of cough syrup every 4 to 6 hours.

Will my dose go up or down?

If you get side effects your dose may go down.

If your symptoms don't go away, your dose might go up or you may be prescribed a different medicine.

Talk to your doctor if your pain or diarrhoea isn't relieved by the dose of codeine prescribed for you, or if side effects bother you or don't go away.

How long will I take it for?

You might only need to take codeine for a few days.

Sometimes, you may need to take codeine for longer. But usually a different medicine will be prescribed for long term pain or diarrhoea, especially if you have side effects like constipation.

What if I forget to take it?

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 your medicine.

What will happen if I stop taking it?

If you need to take codeine 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 codeine, talk to your doctor first. Your dose can be reduced gradually so you don't get unpleasant withdrawal symptoms.

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

• feeling agitated
• feeling anxious
• shaking
• sweating

What if I take too much?

Taking too much codeine 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 codeine that can lead to an overdose varies from person to person.

Storing codeine

If you've been prescribed codeine, 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 codeine to your pharmacist. They will dispose of it.

It's safe to take codeine with paracetamol, ibuprofen or aspirin (aspirin is suitable for most people aged 16 years and over).

Some painkillers that you can buy without a prescription from pharmacies contain codeine. They include co-codamol, Nurofen Plus and Solpadeine.

Do not take codeine-containing painkillers that you can buy alongside prescribed codeine. You'll be more likely to get side effects.

Like all medicines, codeine can cause side effects in some people - but many people have no side effects or only minor ones.

The higher the dose of codeine 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 (nausea or vomiting)
• feeling sleepy
• confusion, feeling dizzy and vertigo (a sensation of spinning)
• dry mouth
• headaches

Serious side effects

Serious side effects happen in less than 1 in 100 people. Call a doctor straight away if you get:

• breathing difficulty or short shallow breathing
• muscle stiffness
• symptoms of low blood pressure which include feeling dizzy and tired
• (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 codeine.

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

What to do about:

• constipation - try to get more fibre into your diet 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. It's safe to use a laxative if your constipation doesn't go away. Usually, lactulose is best but check with a pharmacist or doctor first.
• feeling or being sick (nausea or vomiting) - take codeine with or just after a meal or snack to ease feelings of sickness. If you're being sick, try small frequent sips of water. This side effect should normally wear off after a few days. Talk to your doctor about taking an anti-sickness medicine if it carries on for longer.
• feeling sleepy - this side effect should go away within a few days as your body gets used to codeine. Talk to your doctor if it carries on for longer.
• confusion, feeling dizzy and vertigo - if codeine makes you feel dizzy when you stand up, try getting up very slowly or stay sitting down until you feel better. If you begin to feel dizzy, lie down so that you don't faint, then sit until you feel better. This side effect should wear off within a few days as your body gets used to codeine. Talk to your doctor if it carries on for longer.
• dry mouth - try chewing sugar-free gum or sucking sugar-free sweets. Your doctor can also prescribe an artificial saliva substitute to keep your mouth moist. This comes as a spray, gel or lozenge.
• headaches - it's safe to take an everyday painkiller such as paracetamol or ibuprofen. Talk to your doctor if the headaches get worse or last longer than a week.

Codeine isn't recommended during pregnancy and while breastfeeding.

In early pregnancy, it's been linked to problems in the unborn baby. If you take codeine at the end of pregnancy there's a risk that your newborn baby may get withdrawal symptoms or be born addicted to codeine.

However, it's important to treat pain in pregnancy. For some pregnant women with severe pain, codeine 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 codeine can affect you and your baby during pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPS) website.

Codeine and breastfeeding

Codeine isn't usually recommended if you're breastfeeding. Small amounts of codeine 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 codeine interfere with each other and increase the chances of you having side effects.

Tell your doctor if you're taking any medicines:

• to help you sleep
• for depression - some types can't be taken with codeine
• for high blood pressure
• to help stop you feeling or being sick
• to treat symptoms of an allergy
• to reduce tension or anxiety
• for mental health problems

Mixing codeine with herbal remedies and supplements

It's not possible to say that complementary medicines and herbal remedies are safe to take with codeine. 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.