Codeine is used to treat mild-to-moderate types of pain.
The most common side-effects are feeling sick, constipation, feeling sleepy, and dry mouth.
Codeine may affect your reactions. When you first start treatment, do not drive until you know how you react.
|Type of medicine||An opioid painkiller (analgesic)|
|Used for||Pain relief|
|Also called||Codeine phosphate|
|Available as||Tablets, syrup (liquid medicine) and injection|
Codeine is an opioid medicine (sometimes called an opiate). It is used to treat mild-to-moderate types of pain. It can be particularly useful when painkillers such as paracetamol and ibuprofen have not been effective. It works by binding to certain tiny areas, called opioid receptors, in your central nervous system (brain and spinal cord). This leads to a decrease in the way you feel pain and your reaction to pain. Codeine is available on a prescription from a doctor.
Codeine is also contained in a number of combination medicines, some of which can be bought over-the-counter, without a prescription, in pharmacies. In particular, it is available in combination with the painkiller paracetamol in a medicine called co-codamol. There is a separate medicine leaflet called Co-codamol for pain relief which explains about this medicine.
Before taking codeine
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, before you start taking codeine, it is important that your doctor knows:
- If you are pregnant or breastfeeding.
- If you have a problem with the way your liver works, or a problem with the way your kidneys work.
- 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 or an abnormal heart rhythm.
- If you have any problems with your thyroid or adrenal glands.
- If you have epilepsy.
- If you have gallstones or a problem with your bile duct.
- If you 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 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, as well as herbal and complementary medicines.
How to take codeine
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about codeine and will provide you with a full list of the side-effects which you may experience from taking it.
- Take codeine exactly as your doctor tells you to. The usual dose for pain relief is 30-60 mg every four hours if needed. The dose should not be repeated more frequently than every four hours, and it is important that you do not take more than a maximum daily amount of 240 mg. As there are several different strengths of tablets available, your doctor or pharmacist will tell you how many tablets to take for each dose. This information will also be printed on the label of the pack to remind you.
- Swallow the tablets with a drink of water. You can take codeine either before or after food, but taking the tablets after food can help prevent feelings of sickness which can occur with the first few doses.
- If you forget to take a dose, take it as soon as you remember and then continue taking your doses every four hours if needed, as before. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- You should not drink alcohol while you are taking codeine. This is because codeine will increase the risk that you experience side-effects from the alcohol, such as feeling dizzy and sleepy.
- Codeine is likely to affect your reactions and ability to drive. It is an offence to drive while your reactions are impaired. Do not drive until you know how you react, especially when you first start treatment. Please also be aware that the effects of codeine can last into the following day. Even if your driving ability is not impaired, you are advised to carry with you some evidence that the medicine has been prescribed for you - a repeat prescription form or a patient information leaflet from the pack is generally considered suitable.
- You will not be given codeine for longer than is necessary. This is because when you take codeine repeatedly over a period of time and then stop taking it, it can cause withdrawal symptoms such as making you feel restless or irritable. If you have been taking it for some time and want to stop it, your doctor will recommend that you reduce your dose slowly in order to avoid the risk of these effects.
- Codeine is normally prescribed for short periods of pain. If you take it over a longer period of time, your body can become used to it and it will not work as well. This is called tolerance.
- If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking codeine.
- If you buy any medicines, check with a pharmacist that they are safe to take with codeine.
Can codeine cause problems?
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 codeine. 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 codeine side-effects||What can I do if I experience this?|
|Feeling sick (nausea) or being sick (vomiting)||Stick to simple meals - avoid rich or spicy foods. Also, try taking your doses of codeine after food, as this may help protect your stomach|
|Constipation||Eat a well-balanced diet and drink plenty of water each day. If this continues to be a problem, speak with your doctor|
|Feeling dizzy or sleepy||If this happens, do not drive and do not use tools or machines. Do not drink alcohol|
|Dry mouth, sweating, tummy pain (may be caused by spasm of the bile ducts)||Speak with your doctor if troublesome|
If you experience other symptoms which you think may be due to codeine, speak with your doctor or pharmacist for further advice.
How to store codeine
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
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 and references
; Actavis UK Ltd, The electronic Medicines Compendium. Dated September 2016.
British National Formulary 74th Edition (Sep 2017); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.