Codeine

Other names

Codeine may also be known by a brand or trade name. Some common examples are:

How is codeine used?

Codeine is usually swallowed but can also be used as a suppository or intramuscular injection.⁷

Effects of codeine

The use of any drug can have risks. It’s important to be careful when taking any type of drug.

Codeine can affect everyone differently, based on:

• size, weight and health
• whether the person is used to taking it
• whether other drugs are taken around the same time
• the amount taken
• the strength of the drug (varies from batch to batch)
• the environment (where the drug is taken).

Onset and duration of effects

How fast a drug takes effect and how long it lasts can vary depending on how it's taken - for example, whether it's swallowed or injected.⁸

If swallowed, effects may be felt within 30 to 60 minutes, and last for 3 to 6 hours.^{4, 9}

Effects

The most common side effects of codeine are:

• pain relief
• intense pleasure
• dizziness
• tiredness
• confusion
• difficulty concentrating
• restlessness
• blurred vision
• dry mouth
• limbs feeling heavy
• muscles feeling stiff
• sweating
• mild allergic rash, itching and hives
• low blood pressure
• decreased heart rate, palpitations
• stomach-ache
• nausea
• vomiting
• severe constipation
• blocked bowel
• difficulty urinating.^{5, 10}

Impact of mood and environment

Drugs that affect a person’s mental state (psychoactive drugs) can also have varied effects depending on a person’s mood (often called the ‘set’) or the environment they are in (the ‘setting’):

• Set: a person’s state of mind, previous encounters with the drug, and expectations of what’s going to happen. For example, feelings of stress or anxiety before using codeine may result in an unpleasant experience and make those feelings worse.
• Setting: the physical and social environment where you take codeine – whether it’s known and familiar, who you're with, if you're indoors or outdoors, the type of music or sounds, and lighting. The ideal setting to take codeine will vary based on the individual.¹¹

Being in a good state of mind, with trusted friends and a safe environment before taking codeine reduces the risk of having a bad experience.¹¹

Overdose

If you take a large amount of codeine or use a strong batch, you could overdose.^{1, 5, 12}

Your risk of overdose can also increase if you mix codeine with alcohol or other drugs, including medications.^{1, 5, 12}

Codeine overdose can cause death.^{1, 5, 12}

Call triple zero (000) and request an ambulance if you or someone else has any of the following symptoms (emergency services are there to help and can provide more instructions).

Signs of opioid overdose can include:

• unconscious or non-responsive
• slow breathing, abnormal breathing, or not breathing at all
• slow or no heartbeat and pulse
• choking or gurgling sounds
• skin colour changes, especially lips and fingernails
• bluish-purple skin for people with lighter complexions
• greyish or ashen skin for people with darker complexions
• vomiting
• cool or clammy (wet and sweaty) skin
• small ‘pinpoint’ pupils.^{13, 14}

Naloxone

Naloxone (also known as Nyxoid®/Narcan®) temporarily reverses the effects of opioid overdose (including codeine). It’s available for free over the counter from most local pharmacies and can be administered by anyone, including family or friends and bystanders.¹⁵

If a person does not respond to the first dose after 3 minutes, give them a second dose. This can be repeated until the ambulance arrives.^{16, 17}

Mixing codeine with other drugs

Mixing codeine with other drugs can have unpredictable effects and increase the risk of harm.

Mixing includes using more than one drug (including alcohol or medications) at the same time, or one after another. You should also consider what drugs you’ve taken in the last 24 hours.

• Codeine and stimulants (methamphetamine, cocaine): can cause risk of heart strain and respiratory arrest.
• Codeine and GHB/GBL: can cause difficulty breathing, passing out, and possible death.
• Codeine and Ketamine: can cause nausea, vomiting, passing out and possible death.
• Codeine and benzodiazepines/alcohol: can cause overdose, passing out, difficulty breathing, memory loss and possible death.
• Using more than one drug or type of drug at the same time is called polydrug use.^{14, 18-20}

Reducing harm 

There are ways you can reduce the risk of harm when using codeine

• If you have a prescription, take codeine as advised.
• Start low, go slow – if you don’t have a codeine prescription, try a little bit first to see how you feel and leave plenty of time before redosing. Codeine can stay in your system for many hours after you stop feeling the effects.
• Test your drugs if there is an available drug checking (pill testing) service near you, to find out what the drugs contain and how strong they are.
• Stay hydrated by taking small sips of water regularly – to avoid dehydration.
• Avoid operating machinery, driving, or swimming.^{18, 21-23}

If snorting

• Crush tablets into a fine powder, as crystals can cause cuts.
• Use your own straw, or a disposable one, and avoid money notes to reduce the risk of infections or transmission of viruses like HIV or Hep C.
• Switch nostrils and take breaks to avoid nasal damage.^{18, 21, 23, 24}

If injecting

• Always use new needles – never share needles or other injecting equipment. Use your own spoon/cup and tourniquet. Use new barrels, filters, sterile water, and swabs. Safely dispose of used equipment.
• Visit a needle and syringe program for sterile equipment, disposal of used equipment, and expert medical advice.^{18, 21-23}

Coming down

Codeine is not known to cause comedown effects.

Long-term effects

Long-term effects can vary depending on how much, how often and how codeine is consumed. Regular use may eventually contribute to:

• constipation
• reduced sex drive
• irregular periods
• tension and muscle twitches
• needing to use more to get the same effect
• tolerance and dependence on codeine.^{6, 10, 25}

Codeine and mental health

Research has found a link between some mental health conditions and the risk of opioid overdose, including codeine.^{26, 27}

There is evidence that as many as 1 in 3 people with an opioid use disorder also have post-traumatic stress disorder (PTSD).²⁸

People experiencing mental health concerns such as depression, anxiety, PTSD, psychosis, or bipolar disorder are also more likely to experience an opioid overdose compared to those without these conditions.²⁶

This association has been seen across different groups, including people in emergency departments, veterans, and those in prison settings.²⁶

Tolerance

Regularly taking codeine can lead to developing a tolerance, which means you need to take larger amounts to get the same effects.^{1, 3, 5}

Dependence

People who regularly use codeine may become dependent. They may feel they need to use codeine to go about usual activities like working, studying and socialising, or just to get through the day.^{1, 3, 5}

Withdrawal

Withdrawal refers to the symptoms that can occur when someone who is dependent on a drug, or who has been using it regularly over time, stops or reduces their use.²⁹

Withdrawal can include physical symptoms (such as headaches, or nausea) and psychological symptoms (such as anxiety, or depressed mood).²⁹

Symptoms - including how strong they are and how long they last - will vary depending on the type of drug and a person’s history of use.²⁹

Withdrawal from codeine can be potentially life-threatening. 

If you, or someone you care about, is planning to stop taking codeine after using it for a long time, it’s important to speak with a medical professional for guidance and supervision.

Withdrawal symptoms

Reducing, or stopping using codeine after a period of regular use can lead to withdrawal symptoms, including:

• cravings for codeine
• dilated pupils
• abdominal cramps
• diarrhoea
• nausea, vomiting
• lack of appetite
• flu like symptoms such as runny nose, sneezing, sweating, chills and fever
• yawning and difficulty sleeping
• trembling, aching muscles and joints
• goosebumps
• restlessness
• irritability
• nervousness
• depression.^{10, 25}

Withdrawal symptoms usually start within a few hours after the last dose and become strongest between 48 and 72 hours. Depending on the type of opioid used, withdrawal symptoms can last between 3 to 10 days.^{30, 31}

Reduced tolerance and overdose risk

After withdrawing from opioids such as codeine, your body is no longer used to it and your tolerance drops.²²

This means if you use the same amount as before, it can be too much for your body and cause an overdose.²²

Always start with a lower dose after a break from codeine or other opioid drugs.²²

Pregnancy, breastfeeding and codeine

Before pregnancy

There is research that shows opioid drugs, including codeine and medications containing codeine, may impact fertility.^32-36

Opioids can:

• affect menstrual cycles
• lower sex drive.
• lower testosterone levels
• reduce sperm quality and movement
• cause erectile dysfunction.^33-35

During pregnancy

Opioid use during pregnancy can harm the baby’s development.^{32, 36}

Opioids can pass to your baby via the placenta. This can affect the baby’s growth and result in a premature (early) birth, which has other health impacts on the baby.⁴⁰

Other chemicals may be present in illegal or counterfeit (fake) codeine medication, and there is no way to know exactly how these will impact the baby or the pregnancy.³⁷

If you’re injecting opioids, it’s important to not share injecting equipment with other people. This protects you and the baby from bloodborne viruses such as HIV and hepatitis C.²³

After pregnancy

If you regularly use opioids while pregnant, it’s possible that your baby will experience withdrawal symptoms when they are born.^{36, 38}

This is known as neonatal opioid withdrawal syndrome (NOWS).³⁸

If the baby does show signs of NOWS, they are provided with the appropriate treatment, which can vary from extra feeding and cuddles, through to specialised medications to make sure they are comfortable and feeding.³⁸

Breastfeeding your baby while using opioids in high doses is not recommended, as the drugs can be present in breastmilk and affect the baby.^{32, 38-41}

If you’re planning to breastfeed, make sure you talk with your midwife or doctor about your use of opioids.³⁶

Getting help

If your use of codeine is affecting your health, family, relationships, work, school, financial or other life situations, or you’re concerned about someone, there is help and support. 

• Call the National Alcohol and Other Drug Hotline on 1800 250 015 for free and confidential advice, information and counselling about alcohol and other drugs.
• Search our Help and Support directory to find your preferred support, by adding your location or postcode and filtering by service type.