Codeine phosphate is a medicine used to relieve pain, calm a dry cough, and sometimes help with ongoing diarrhoea. It belongs to a group of medicines called opioids. Opioids can be very useful when used correctly, but they can also be risky if taken in the wrong way.
Codeine phosphate is usually taken as a tablet, capsule, syrup, or liquid. In South Africa and many other countries, codeine may be found on its own or mixed with other medicines, such as paracetamol, ibuprofen, aspirin, or cough-and-cold ingredients.
Even though codeine is sometimes seen as a “milder” opioid, it is still a strong medicine. It can cause sleepiness, constipation, dizziness, dependence, withdrawal symptoms, breathing problems, and overdose. For this reason, it should be used carefully and only as directed by a doctor or pharmacist.
How does codeine phosphate work?
Codeine works by changing the way your brain and body respond to pain. After you take it, your body changes some of the codeine into morphine. Morphine then acts on opioid receptors in the brain and nervous system to reduce pain signals.
Codeine can also affect the cough centre in the brain. This is why it may help reduce a dry, irritating cough. In the gut, codeine slows movement, which is why it can reduce diarrhoea. However, this same effect is also why constipation is one of the most common side effects.
People do not all react to codeine in the same way. Some people get very little pain relief from it. Others process codeine very quickly and may get stronger effects than expected. This can be dangerous, especially if it causes breathing to slow down.
What is codeine phosphate used for?
1. Pain relief
Codeine phosphate may be used for mild to moderate pain. A doctor may prescribe it after an injury, dental procedure, operation, or for another painful condition.
It is often used when ordinary painkillers like paracetamol or ibuprofen are not enough, or when they are not suitable for the person.
Codeine is sometimes combined with paracetamol. This can work well for pain, but it also needs extra care. Taking too much of a codeine-and-paracetamol product can cause opioid overdose and serious liver damage from too much paracetamol.
2. Dry cough
Codeine may be used to calm a dry, troublesome cough. It is not usually needed for every cough, and it is not suitable for all people.
A cough can have many causes, such as flu, allergies, asthma, smoking, reflux, chest infection, or another health problem. If a cough is ongoing, severe, or comes with chest pain, fever, shortness of breath, or blood, it should be checked by a healthcare professional.
3. Diarrhoea
Codeine can slow the bowel, so it may sometimes be used for long-term diarrhoea. This should only be done under medical supervision.
It is not always safe to stop diarrhoea without knowing the cause. For example, diarrhoea from infection may need a different approach, and the main priority is often preventing dehydration.
Common side effects
Codeine phosphate can cause side effects, even when taken correctly.
Common side effects include:
- Feeling sleepy or tired
- Dizziness
- Nausea or vomiting
- Constipation
- Dry mouth
- Sweating
- Itching
- Headache
- Stomach discomfort
- Difficulty concentrating
Many people feel drowsy when taking codeine. Do not drive, operate machinery, or do risky tasks until you know how the medicine affects you.
Constipation is also very common. Drinking enough water, eating fibre, and staying active may help, but speak to a pharmacist or doctor if constipation becomes a problem.
Serious side effects
Some side effects need urgent medical help.
Get help immediately if someone taking codeine has:
- Slow, shallow, or noisy breathing
- Extreme sleepiness
- Trouble waking up
- Confusion
- Blue lips or fingertips
- Fainting
- Severe dizziness
- Seizures
- Swelling of the face, lips, tongue, or throat
- A severe rash or allergic reaction
Slow breathing is one of the most dangerous risks of codeine. It can be life-threatening.
Can codeine phosphate be addictive?
Yes. Codeine can be habit-forming.
This does not mean everyone who uses codeine will become addicted. Many people use it safely for a short time. But the risk increases when codeine is used for longer than advised, taken in higher doses, used to relax or sleep, or taken without medical guidance.
There is a difference between dependence and addiction.
Dependence means your body has become used to the medicine. If you stop suddenly, you may feel withdrawal symptoms.
Addiction means a person feels unable to control their use, continues using despite harm, or craves the medicine.
Possible withdrawal symptoms include:
- Restlessness
- Anxiety
- Sweating
- Runny nose
- Muscle aches
- Trouble sleeping
- Stomach cramps
- Diarrhoea
- Nausea
- Irritability
- Cravings
If you have been taking codeine regularly, do not stop suddenly unless your doctor tells you to. You may need to reduce the dose slowly.
Codeine and breathing problems
Codeine can slow breathing, especially if too much is taken or if it is mixed with other substances.
The risk is higher in people who:
- Have asthma, COPD, sleep apnoea, or other breathing problems
- Are elderly or frail
- Have liver or kidney problems
- Drink alcohol
- Take sleeping tablets, anxiety tablets, sedatives, or other opioids
- Take more than the recommended dose
- Are unusually sensitive to codeine
Never mix codeine with alcohol. This can be very dangerous and may lead to overdose or death.
Codeine and children
Codeine is not suitable for many children and teenagers. In some children, codeine can be changed into morphine too quickly in the body. This can cause dangerous breathing problems.
Parents and caregivers should never give a child codeine unless it has been specifically prescribed by a qualified healthcare professional.
Also, do not give a child leftover medicine from someone else’s prescription.
Codeine during pregnancy and breastfeeding
Pregnant and breastfeeding women should speak to a doctor before using codeine.
Using opioids regularly during pregnancy may affect the baby and can cause withdrawal symptoms in the newborn after birth.
Codeine can also pass into breast milk. In some cases, this can make a baby very sleepy or cause breathing problems. This is why medical advice is important.
Medicines and substances that should not be mixed with codeine
Codeine can interact with many medicines and substances.
Be especially careful with:
- Alcohol
- Sleeping tablets
- Anxiety medicines such as diazepam or alprazolam
- Other opioid painkillers
- Strong cough medicines
- Muscle relaxants
- Some antidepressants
- Some antipsychotic medicines
- Sedating antihistamines
- Certain cold and flu medicines
Always tell your doctor or pharmacist what else you are taking, including herbal products, supplements, and over-the-counter medicines.
Signs of codeine overdose
A codeine overdose is a medical emergency.
Warning signs include:
- Very slow or shallow breathing
- Extreme drowsiness
- Not waking up
- Blue lips or nails
- Cold or clammy skin
- Limp body
- Confusion
- Vomiting
- Pinpoint pupils
- Weak pulse
- Collapse
If you think someone has overdosed on codeine, call emergency medical help immediately.
In South Africa, you can contact emergency services on 112 from a cellphone.
How to use codeine safely
To use codeine phosphate safely:
- Take it exactly as prescribed or as advised by your pharmacist.
- Do not take extra doses.
- Do not take it more often than instructed.
- Do not mix it with alcohol.
- Do not share it with anyone.
- Do not use it to help you sleep or relax.
- Store it safely away from children and visitors.
- Check whether your medicine contains paracetamol, ibuprofen, aspirin, or other ingredients.
- Ask your pharmacist if you are unsure about anything.
If your pain, cough, or diarrhoea is not improving, do not simply take more codeine. Speak to a healthcare professional.
Why codeine misuse is dangerous
Codeine misuse can happen when someone takes it for reasons other than medical treatment, such as to feel relaxed, sleepy, or “high”. It can also happen when someone takes more than prescribed because the usual dose no longer feels effective.
Misuse can lead to:
- Dependence
- Addiction
- Poor concentration
- Accidents
- Liver damage from combination products
- Breathing problems
- Overdose
- Death
Codeine cough syrups and painkillers are sometimes misused recreationally. This is dangerous, especially when mixed with alcohol, soft drinks, sedatives, or other drugs.
Safer alternatives
There may be safer options depending on the problem.
For pain, a healthcare professional may suggest:
- Paracetamol
- Ibuprofen or another anti-inflammatory
- Heat or cold packs
- Physiotherapy
- Dental treatment
- Treating the underlying cause
For cough, options may include:
- Fluids
- Honey for adults and older children
- Steam or humidified air
- Treating allergies, asthma, reflux, or infection
- Non-opioid cough remedies, where suitable
For diarrhoea, treatment may include:
- Oral rehydration solution
- Fluids
- Diet changes
- Loperamide, if appropriate
- Medical treatment for infection or bowel disease
The best choice depends on the cause, your health history, and other medicines you take.
Important things to remember
Codeine phosphate can be helpful, but it must be treated with respect.
Remember:
Codeine is an opioid medicine.
It can cause drowsiness, constipation, dependence, and breathing problems.
It should not be mixed with alcohol.
It should not be shared with anyone.
It should be stored safely.
Children, pregnant women, breastfeeding mothers, elderly people, and people with breathing problems need special caution.
If you are worried about your use of codeine, speak to a doctor, pharmacist, or clinic. You will not be the first person to ask for help, and support is available.
Conclusion
Codeine phosphate is a useful medicine when used correctly. It can help with pain, dry cough, and sometimes diarrhoea. However, it also has real risks. Because it is an opioid, it can cause dependence, addiction, overdose, and dangerous breathing problems.
The safest way to use codeine is to follow medical advice, take the correct dose, avoid alcohol, and use it only for the reason it was prescribed. If symptoms continue or worsen, speak to a healthcare professional rather than increasing the dose yourself.
This article is for general education only. It does not replace advice from a doctor, nurse, or pharmacist.
