Factsheet

What are opioids?

Image of tablets, tablets in a bottle, and a syringe
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This resource has undergone expert review.

Year:
Year 9–10, Year 11–12
Origin

Australian

Cost

Free

What are opioids?

Opioids are a broad group of drugs that include both illicit drugs and prescription medications. Different opioids have different effects, uses, safety, and legality. Because of this, it can be confusing to tell them apart. In this factsheet, we cover different types of opioids and answer common questions about them, to help you understand the differences.

What do opioids do?

Opioids attach to opioid receptors in the central nervous system, and slow down pain signals between the brain and the body.

What are opioids made from?

Opioids can be naturally derived from the opium poppy. These substances are known as opiates. Examples include opium, heroin (see factsheet), codeine, and morphine.  

Opioids can also be synthetically produced. Examples include oxycodone, fentanyl, and nitazenes.

What are the different forms and types of opioids?

Opioids come in a range of forms, including as powders, tablets, capsules, liquids, and patches.

Some opioids can be prescribed as medication and are legal when used as directed by a doctor (i.e., the prescribed strength, form, and duration of use). These include pain medications (e.g., codeine, oxycodone, morphine) and opioid dependence treatments (e.g., buprenorphine, methadone).

Others, including heroin and opium, are illegal in Australia. This means it is illegal to make, sell or possess them. Over time new opioids have emerged in the illegal drug market (e.g., nitazenes).

Prescription medication

Opioid medicines may be prescribed by doctors to manage pain. If they are used in this way, they can be effective medications. However, there are risks, especially if they are not used properly.

Opioids used in pain management include codeine (Panadeine Forte, Nurofen Plus), tramadol, fentanyl, oxycodone (OxyContin, OxyNorm, Endone), tapentadol (Palexia), morphine, and hydromorphone.

Opioid medications are prescription only in Australia, and are taken through tablets, capsules, injections, liquids, or patches. Doctors prescribe different forms and strengths depending on the patient’s needs. Opioid medicines are legal with a prescription, however using them without a prescription, or misusing them, is considered illicit drug use. Misuse refers to using an opioid differently to how it was prescribed, including taking opioids for a longer period of time or at a higher dose than prescribed. For more information, visit the Department of Health and Aged Care’s ‘Drug laws in Australia’ page.

Versions of common pharmaceutical opioids are manufactured for the illegal drug market. The lack of regulation and quality control in the illegal drug market means people purchasing these do not know the purity, dose, or strength of the opioid they are taking. This increases the risk of negative effects, including overdose.

Opioids used for opioid dependence treatment

Sometimes, specific opioids are prescribed as part of opioid dependence treatments. For people with opioid dependence, these medications can help them recover by attaching to opioid in the central nervous system and reducing the withdrawal symptoms, desire for more opioids, and harms associated with opioid use. They also reduce the ‘high’ users feel when they take other opioid drugs. These medications are prescribed as part of short or long-term treatment plans.

Opioids used in dependence treatment include buprenorphine (Suboxone, Subutex), and methadone (Biodone Forte). They are taken through injections, tablets, films, or as liquids, usually under pharmacist supervision.

Naloxone is a medication that can temporarily reverse the effects of an opioid overdose, by preventing opioids from attaching to opioid receptors. It is given through an injection or nasal spray. As the effects of naloxone are temporary, it is important to call 000 for an ambulance. See below for more information on opioid overdose and naloxone.

Illegal opioids

Some opioids, including heroin (see factsheet) and opium are illegal to make, sell, or possess in Australia.

Heroin (see factsheet) can be a fine powder, granules, or rocks. It is usually injected, but is also snorted, smoked, or heated and the vapours inhaled.

Opium is a dark brown gum extracted from the opium poppy, that is smoked, taken as a pill, or drunk in a tincture.

Using prescription opioids in at a frequency, quantity or by a person other than as directed on the prescription is considered illicit drug use. to the 2022-2023 Australian secondary schools’ survey, 1 in 100 students (1%) had used pharmaceutical opioids in the past month either without a prescription or not as directed, and 1 in 500 (0.2%) had used heroin in the past month.

Emerging opioids

New types of opioids emerge on the illegal market. They can have increased risk as their effects may be different to what people expect.

Nitazenes are an example of emerging opioids that have been detected in Australia. Nitazenes are strong synthetic opioids that were originally developed as medicines. However, they were not approved for medical use due to safety concerns. Recently, nitazenes have been found in drugs sold as heroin, MDMA, and ketamine. As nitazenes can be much stronger than the drugs people think they are taking, this increases the risk of overdose and negative effects. Visit theknow.org.au for more information about emerging drugs of concern.

What are the effects of opioids?

Opioids are depressants, which means they slow down the body’s central nervous system and the messages going between the brain and body.

The effects of opioids can be immediate or long-term, as listed in the table below.

Immediate Long-term
Relaxation Dependence (see glossary)
Drowsiness and sedation (a state of calm or sleep) Withdrawal (see glossary)
Dizziness Organ damage
Headache Tolerance (needing to take a higher dose to feel pain relief)
Pain relief Depression
Slow breathing and heartbeat  
Constipation  
Nausea and vomiting  
Confusion   
Overdose  
Coma  

People who take opioids for longer periods of time, or at higher doses, are more likely to experience harms. Using opioids with other drugs, in particular alcohol or benzodiazepines, can increase the risk of harms. Find out more in .

Side effects, including dependence, can occur from any form of opioid. It’s important to take prescription opioids as directed, to minimise the risk of side effects, dependence, and withdrawal. Talk to a medical professional for advice on managing side effects and reducing risks.

Withdrawal

Withdrawal symptoms can happen when someone stops taking opioids. A person is more likely to have withdrawal symptoms if they have taken opioids for a long time or at a high dose.

Symptoms can include:

  • Diarrhoea
  • Sweating
  • Nausea
  • Muscle aches
  • Anxiety
  • Cravings

Withdrawal symptoms can be managed with medical guidance. It is important that you talk to your doctor and develop a plan to safely reduce opioid intake, as withdrawal symptoms can be serious.

Overdose

Overdose happens when a person takes a toxic amount of a drug. Overdoses can happen if too high a dose is taken, if the person has other drugs in their system (e.g., alcohol, benzodiazepines, or other opioids), or if they have decreased tolerance.

Signs of overdose include:

  • Extreme drowsiness
  • Loss of consciousness or responsiveness
  • Vomiting
  • Slowed breathing and heart rate
  • Blue or grey coloured skin

Naloxone is a medication that can temporarily reverse the effects of an opioid overdose. For more information about opioid overdose and naloxone, see here. Call 000 even if naloxone has been given.

See ‘How to help someone who has taken a drug’.

Evidence Base

This factsheet was developed following expert review by researchers at the Matilda Centre for Research in Mental Health and Substance Use at the University of Sydney.

Page last reviewed: 3/07/2024

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