Prescription drugs pain killers

Last published: November 21, 2023

Codeine is an opioid. Opioids are drugs that act on the opioid receptors in the brain, they include both natural and synthetic drugs that are derived from, or related to, the opium poppy.1

Opioids bring about a range of responses, from feelings of pain relief to relaxation, pleasure and contentment.

Some people use non-prescribed codeine as a coping mechanism for chronic pain, mental health issues such as depression or anxiety, or to get high.

What does codeine look like?

Codeine comes in the following forms:

  • tablets
  • capsules
  • suppositories
  • soluble powders and tablets
  • liquids.2

Other types of opioids

Other names

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

Generic name Brand names
Aspirin and codeine Aspalgin®, Codral Cold & Flu Original®
Ibuprofen and codeine Nurofen Plus®
Paracetamol and codeine Panadeine Forte®, Panamax Co®
Paracetamol, codeine and doxylamine Mersyndol® and Mersyndol Forte®, Panalgesic®

How is codeine used?

Codeine is usually swallowed but can also be used as a suppository or intramuscular injection.5

Effects of codeine

There is no safe level of drug use. Use of any drug always carries some risk – even medications can produce unwanted side effects. It’s important to be careful when taking any type of drug.

Codeine affects everyone differently, based on:

  • the person’s size, weight and health
  • whether the person is used to taking it
  • whether other drugs are taken around the same time
  • the amount taken.

Codeine is used for relief from various conditions, including:

  • mild to moderate pain
  • severe pain (when combined with aspirin or paracetamol)
  • dry irritating cough
  • diarrhoea
  • cold and flu (when combined with antihistamines and decongestants).2

Side effects

The most common side effects of codeine are:

  • dizziness
  • tiredness
  • confusion, difficulty concentrating
  • euphoria
  • restlessness
  • blurred vision
  • dry mouth
  • limbs feeling heavy or muscles feeling stiff
  • sweating
  • mild allergic rash, itching and hives
  • low blood pressure
  • decreased heart rate, palpitations
  • stomach-ache, nausea, vomiting, constipation
  • difficulty urinating.6,7

These side effects may disappear with continued treatment. However, if they persist, speak to a medical practitioner.


If the dose is too high, you might overdose. Call an ambulance straight away by dialling triple zero (000) if you or someone else has any of these symptoms (ambulance officers don’t need to involve the police):

  • inability to pass urine
  • severe constipation and obstructed bowel
  • agitation
  • cold clammy skin with a bluish tinge
  • mental numbness
  • very slow, shallow breathing
  • hallucinations and sometimes seizures
  • coma and death.1

Long-term effects of codeine

Regular use of codeine may eventually cause:

  • constipation
  • reduced sex drive
  • irregular periods
  • tension and muscle twitches
  • needing to use more to get the same effect
  • tolerance and dependence on codeine
  • financial, work and social problems.2,7,12

It’s important to discuss the side effects of long-term use with a medical practitioner.

Tolerance and dependence

People who use codeine regularly can develop dependence (addiction) and tolerance to it. This means they need to take larger amounts of the drug to get the same effect.5

Mixing codeine with other drugs

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

  • Codeine and 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.8,9,11

More on polydrug use

'Polydrug use’ is a term for the use of more than one drug or type of drug at the same time or one after another. Polydrug use can involve both illicit drugs and legal substances, such as alcohol and medications.


Reducing harm

  • Always carry naloxone for emergencies, and encourage family and friends to learn how to use take home naloxone – a medicine that can reverse the effects of an opioid overdose (more information on naloxone is provided below).
  • Avoid mixing drugs (polydrug use) – mixing opioids with depressant drugs such as alcohol or benzodiazepines can greatly increase the risk of overdose.
  • Use codeine where you feel safe and with people you trust, and always tell someone what you’ve taken.
  • Test a small amount first to reduce overdose risk.
  • Do not drive or operate machinery after use.
  • Always use sterile injecting equipment and never share injecting equipment.
  • Safely dispose of used injecting equipment.8-11

'Polydrug use’ is a term for the use of more than one drug or type of drug at the same time or one after another. Polydrug use can involve both illicit drugs and legal substances, such as alcohol and medications.


Giving up codeine after a long time is challenging because the body has to get used to functioning without it. Please seek advice from a health professional.

Withdrawal symptoms usually start within a few hours after the last dose and become strongest between 48 and 72 hours.13 Symptoms include:

  • cravings for codeine
  • seeking codeine containing medicines
  • 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.6,12,7

Getting help

If your use of Codeine is affecting your health, family, relationships, work, school, financial or other life situations, you can find 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

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  1. John Hopkins Medical. What are opioids? n.d. [03.01.2022]. Available from:
  2. Upfal J. Australian drug guide: the plain language guide to drugs and medicines of all kinds. 8th ed. Carlton, Vic, Australia: Black Inc., an imprint of Schwartz Publishing Pty Ltd; 2016.
  3. Van Hout MC, Rich E, Dada S, Bergin M. Codeine Is My Helper: Misuse of and Dependence on Codeine-Containing Medicines in South Africa. Qual Health Res. 2017;27(3):341-50.
  4. Cairns R, Schaffer AL, Brown JA, Pearson SA, Buckley NA. Codeine use and harms in Australia: evaluating the effects of re‐scheduling. Addiction. 2019;115(3):451-9.
  5. Brands B, Sproule B, Marshman J, Ontario. Addiction Research F. Drugs & drug abuse: a reference text. Toronto, Ont.: Addiction Research Foundation; 1998 [cited 2021 May].
  6. Upfal J. The Australian drug guide : every person's guide to prescription and over-the-counter medicines, street drugs, vaccines, vitamins and minerals. 7th edition. ed. Melbourne, Vic.: Black Inc.; 2006.
  7. Kane BM, Triggle DJ. Codeine. Triggle DJ, editor. New York: Chelsea House; 2007.
  8. Harm Reduction Victoria. Opioids n.d. [cited: 05.01.2022].
  9. Psychonaut Wiki. Opioids 2022 [cited: 05.01.20022].
  10. Psychonaut Wiki. Methoxetamine 2020
  11. Hi-Ground. Opioids n.d. [cited: 05.01.2022].
  12. Marshman JA, Brands B, Sproule B, Jacobs MR. Drugs & drug abuse: a reference text. 3rd ed. Marshman JA, Brands B, Sproule B, Jacobs MR, Kevin O'B F, Addiction Research Foundation of Ontario, editors. Toronto: Addiction Research Foundation; 1998.
  13. Mental Health and Drug & Alcohol Office. NSW Drug and Alcohol Withdrawal Clinical Practice Guideline. NSW Department of Health; 2007, reviewed 2018.

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blurred vision, confusion, constipation, difficulty urinating, dizziness, dry mouth, euphoria, heart palpitations, hives, itching, nausea, sweating, tiredness, treat cold and flu, treat cough, treat diarrhoea, treat severe pain, treats mild pain, vomiting