Codeine phosphate 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 paracetamol, ibuprofen, and aspirin have not worked.
Codeine is also used to treat diarrhea.
Codeine phosphate is available on prescription. It comes as tablets, a liquid to swallow, and as an injection. Codeine phosphate injections are usually only given in hospitals. You can buy lower-strength codeine from a pharmacy. It comes mixed with paracetamol (co-codamol) or with aspirin (co-codaprin) or ibuprofen (Nurofen Plus).
You can also buy codeine from a pharmacy as a syrup (linctus) to treat dry coughs.
How and when to take it
Follow your doctor’s instructions about how to use this medicine. This is particularly important because codeine can be addictive.
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.
Dosage and Administration
For Analgesia: Dosage should be adjusted according to the severity of the pain and the response of the patient.
Adults: 15 to 60 mg every 4 to 6 hours (usual adult dose, 30 mg).
Children: 1 Year of Age and Older – 0.5 mg/kg of b.d. weight or 15 mg/m2 of b.d. surface every 4 to 6 hours.
Soluble tablets of codeine phosphate are administered subcutaneously or intramuscularly.
Solutions for injection should be prepared with sterile water and filtered through a 0.22 membrane filter.
Note: Do not use the solution if it is more than slightly discolored or contains a precipitate.
How long does codeine take to work
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 diarrhea, especially if you have side effects like constipation.
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