Codeine is a painkiller that is part of a group of medicines called opiates. It's used to treat pain, for example, after an operation or an injury. It's also used for ongoing pain when painkillers such as paracetamol, ibuprofen and aspirin have not worked. Codeine is also used to treat diarrhoea.
It works in the central nervous system and the brain to block pain signals to the rest of the body. It also reduces the anxiety and stress caused by pain.
Codeine is available on prescription and comes as tablets, a liquid you swallow and as an injection. Codeine injections are usually only given in hospital.
Pharmacies also sell codeine as a syrup (linctus) to treat dry coughs.
Who can take codeine
Codeine is not suitable for some people. To make sure it's safe for you, tell your doctor before starting the medicine if you have:
- ever had an allergic reaction to codeine or any other medicine
- a lung problem
- a head injury
- adrenal gland problems
- a condition which causes seizures or fits
- an addiction to alcohol
- an underactive thyroid gland
- kidney or liver problems
- an enlarged prostate
- low blood pressure
- myasthenia gravis, a rare illness that causes muscle weakness
- symptoms of ulcerative colitis, a bowel condition
- been trying to get pregnant, are already pregnant or breastfeeding – codeine is not generally recommended during pregnancy or breastfeeding
Do not give codeine to children who are under 18 if they have had their tonsils or adenoids removed because of a sleep problem called obstructive sleep apnoea (OSA). This is because:
- OSA can cause breathing problems while sleeping
- codeine can also cause breathing problems
Giving codeine to a child with this condition could be dangerous because of this.
Dosage and strength
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)
The usual dose of codeine is 15mg to 60mg.
The usual dose for treating pain is:
- adults – one or two 30mg tablets, taken every 4 hours, up to a maximum of 8 tablets (240mg) in 24 hours
- children (aged 12 to 17 years) – one or two 30mg tablets (or one or two 5ml spoonfuls of liquid), taken every 6 hours
- older people or people with kidney or liver problems – one 15mg tablet, taken every 4 hours
The usual dose for treating diarrhoea is:
- adults – one or two 30mg tablets (or one or two 5ml spoonfuls of liquid)
- children (aged 12 to 17 years) – one or two 30mg tablets (or one or two 5ml spoonfuls of liquid)
- older people, or people with kidney or liver problems – one 15mg tablet
You can take this dose 3 or 4 times a day.
The usual dose for treating a cough is:
- adults and children – one or two 5ml spoonfuls of cough syrup, taken 3 or 4 times a day
It's important not to take more than your prescribed dose. Do not take more than 4 doses of codeine in 24 hours if you're:
- a child (aged 12 to 17 years)
- taking a 60mg dose
If you get side effects from taking codeine, your doctor may lower your dose.
If your symptoms do not go away, your doctor may increase your dose or prescribe a different medicine.
Talk to your doctor if your pain or diarrhoea is not relieved by the dose of codeine prescribed for you, or if side effects bother you or do not go away.
How to take it
Swallow your codeine tablet whole with a drink of water. Take it 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.
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 do not have it. Do not measure the liquid with a kitchen teaspoon because it will not give the right amount.
How long to take it for
You might only need to take codeine for a few days. Sometimes, you may need to take it for longer. But usually, a different medicine will be prescribed for long-term pain or diarrhoea, especially if you have side effects like constipation.
If you forget to take it
If you forget to take a dose, check the information on the 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.
If you take too much
It's important not to take more than your prescribed dose, even if you think it's not enough to relieve your pain. Speak to your doctor first, if you think you need a different dose.
Taking too much codeine can be dangerous. It may make you 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.
- you've taken more than your recommended dose of codeine
If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance. Take the codeine box or leaflet inside, plus any remaining medicine with you.
- you have taken more than your recommended dose of codeine and are having problems with your breathing
- you are losing consciousness – if you're with someone, ask them to call for you
If you have been taking codeine for a long time and want to stop, talk to your doctor first. Your dose can be reduced gradually so you do not get withdrawal symptoms. If you stop taking it suddenly, it can cause:
If you have been taking codeine for more than a few weeks, do not stop taking it without speaking to your doctor first.
If you've been prescribed codeine, it's particularly important to:
- store it properly and safely at home
- keep it out of the sight and reach of children
- never share your medicine with anyone else
Return any unused codeine to your pharmacist. They will get rid of it.
Common side effects
These common side effects of codeine happen in more than 1 in 100 people. There are things you can do to help cope with them:
If this advice does not help and any of these side effects continue to bother you, speak to your doctor or pharmacist.
Serious side effects happen in less than 1 in 100 people.
Call a doctor or contact 111 now if you:
- have muscle stiffness
- get symptoms of low blood pressure, which include feeling dizzy and tired
- you have breathing difficulty or short, shallow breathing
- you have a fit or seizure
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.
Codeine and pregnancy
Codeine can be taken in pregnancy, although long-term use is not recommended.
If you take codeine at the end of pregnancy there's a risk that your baby will be used to having codeine. This means that they may have withdrawal symptoms. If this happens, your baby may need extra time in hospital after delivery for observation.
It is important to treat pain in pregnancy. For some pregnant women with severe pain, codeine might be the best option. Your doctor can help you decide what's right for you and your baby.
Do not take codeine if you're breastfeeding. Small amounts of codeine pass into breast milk and can cause breathing problems in your baby and make them feel drowsy.
Talk to your doctor or pharmacist, as they will be able to recommend a more suitable painkiller.
Codeine and fertility
If you're taking codeine for a short time and at normal doses, there's no evidence that it reduces fertility in either men or women.
However, if you've been taking it for a long time and you're concerned about your fertility, or you're trying to get pregnant, speak to a pharmacist or your doctor.
Cautions with other medicines
Some medicines can affect the way codeine works, 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 cannot 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
If you are taking prescribed codeine, do not take painkillers that contain codeine that you have bought from a pharmacy at the same time. You'll be more likely to get side effects.
Mixing codeine with herbal remedies and supplements
It is not possible to say that herbal remedies and supplements are safe to take with codeine. They are not tested in the same way as pharmacy and prescription medicines, and are generally not tested for the effect they have on other medicines.
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