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Key points about codeine

  • Codeine is used for pain relief.
  • Codeine belongs to a group of medicines known as analgesics (painkillers).
  • Find out how to take it safely and possible side effects.
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Codeine is used for the relief of moderately severe pain, such as after an injury or operation. It's usually used when milder pain relief such as paracetamol or non-steroidal anti-inflammatories (NSAIDs) don’t work well enough.

Codeine belongs to a group of medicines called opioid painkillers. They act on your brain and nervous system to lessen the way you feel pain. Other pain relievers such as paracetamol and NSAIDs (ibuprofen, diclofenac, naproxen) may also be used with codeineRead more about painpain-relief medication and opioid painkillers.

Codeine can also be used to treat dry cough and diarrhoea.

Use in children and adolescents

New Zealand's Medsafe, a unit of Health New Zealand | Te Whatu Ora, has assessed the safety and effectiveness of codeine in children and adolescents. Codeine can cause serious breathing problems in children that could result in death. 

  • Medsafe has advised that codeine should not be used in children younger than 12 years.
  • In adolescents aged 12–18 years, codeine should not be used for pain after surgery to remove tonsils or adenoids, for relief of cough, or in people who have breathing problems.

Codeine is also called:

  • Codeine Phosphate®
  • Panadeine
  • Panadeine Extra
  • Panadeine Plus 
  • Ibucode Plus®
  • Nurofen Plus®
  • Panafen Plus® 

All codeine-containing medicines are only available on a prescription from your doctor. Read more about codeine re-classification(external link)

  • The dose of codeine is different for different people. 
  • Always take codeine exactly as your doctor has told you.
  • Depending on the reason you are taking codeine, your doctor may advise you to take regular doses or take it only when you need it for relief. Make sure you know how you are to take it.
  • The pharmacy label on your medicine will tell you how much codeine to take, how often to take it and any special instructions.

Variations in response to codeine

Codeine is broken down in your liver to morphine, which is a strong pain reliever. People may respond differently to codeine depending on how their liver breaks down codeine.

  • Some people are poor metabolisers, which means that they are unable to convert codeine to morphine, and don't get enough pain relief.
  • Some other people break down codeine very quickly (ultra-rapid metabolisers) and are at increased risk of developing side effects, even at low doses.
  • Estimates suggest that up to 10% of the European/Pākehā population may be poor or ultra-rapid metabolisers. The prevalence in Māori and Pasifika people is not known.
  • If you are taking codeine for pain relief, and it doesn’t seem to be working, let your doctor know.
  • If you are taking codeine and get side effects such as nausea, vomiting, constipation, lack of appetite, drowsiness or extreme sleepiness, let your doctor know. Other options may be better for you. 
  • If you have more severe side effects, such as difficulty waking, confusion or shallow breathing, let your doctor know straight away or call Healthline 0800 611 116.

  • You can take codeine with or without food.
  • Stop taking codeine if your symptoms are relieved. 
  • Limit or avoid drinking alcohol while you are taking codeine. Combining codeine with alcohol can make you sleepy, drowsy or dizzy.

  • Are you pregnant or breastfeeding?
  • Do you have problems with your liver or your kidneys?
  • Do you have problems with your prostate or any difficulties passing urine (peeing)?
  • Do you have any breathing problems, such as asthma or chronic obstructive pulmonary disease (COPD)?
  • Have you had a recent head injury?
  • Do you suffer from constipation, eg, constipated for more than a week?
  • Do you have an inflammatory bowel problem?
  • Have you ever been dependent on drugs or alcohol?

If so, it’s important that you tell your doctor or pharmacist before you start codeine. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Here are some things to know when you're taking codeine. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Other medicines: Codeine may interact with a few medicines and herbal supplements, so check with your doctor or pharmacist before starting codeine or before starting any new medicines. It may interact with medicines available without a prescription such as:
    • cough suppressants (eg, Benadryl Dry Forte®, Duro-Tuss®)
    • sedating antihistamines (eg, Phenergan®).

Like all medicines, codeine can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.


Addiction is an excessive craving. If you are addicted to codeine, it means you are not able to control your use of it. It is unusual for people who are prescribed codeine for short periods of time to become addicted to it.

Some people are more likely to develop addiction than others. You may be at risk for addiction if you have mental health problems such as depression or a history of substance abuse, including alcohol and recreational drugs.

To reduce your risk of addiction, codeine should be used for the shortest possible time, at the lowest effective dose, with a plan in place to reduce and withdraw treatment.

Other side effects

Side effects What should I do?
  • Feeling sleepy, dizzy or tired
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Feeling sick or vomiting
  • Try taking codeine after meals.
  • Tell your doctor if this is troublesome.
  • Constipation
  • Headache, dry mouth, altered vision, skin rash and itching
  • These are quite common when you first start taking codeine, and usually go away with time.
  • Breathing difficulties, changes to your heartbeat
  • Tell your doctor immediately or phone Healthline 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)



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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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