Last published: January 10, 2023

What is fentanyl?

Fentanyl is an opioid.

Opioids interact with opioid receptors in the brain and bring about a range of responses from feelings of pain relief to relaxation, pleasure and contentment.

It’s prescribed for chronic, severe cancer pain, nerve damage, back injury, major trauma and surgery.1 In Australia, fentanyl is a Schedule 8 drug.2 It’s about 80 to 100 times stronger than morphine.3

What it looks like

Fentanyl is available in many forms. Pharmaceutical fentanyl is used for managing acute or chronic pain. Illicit fentanyl can be manufactured for use in the illegal drug market.

Medicinal use

Medicinal fentanyl comes in a number of different forms and strengths including:

  • transdermal patches (Durogesic®, APO-fentanyl® and generic versions)
  • lozenges/lollipops (Actiq®)
  • intravenous injection (Sublimaze® B. BRAUN FENTANYL®).

Illicit use

Some people use fentanyl illegally by extracting it from the patch and injecting it. This is very risky as it is extremely hard to judge a dose size.

Fentanyl can be ‘diverted’ meaning that when the medication is prescribed by a medical professional, it’s not used as directed, or is given or sold to a third party.

Prescribed fentanyl can be 'diverted' when individuals:

  • obtain medication without a prescription from another doctor through their profession (e.g. healthcare professionals)
  • use their own prescribed medication recreationally
  • use medication prescribed for another person.

Fentanyl is sometimes mixed with other drugs to increase its potency. Illicitly manufactured fentanyl can be:

  • a stand-alone product
  • a low-cost additive to increase the potency of other illicit drugs such as heroin
  • sold as counterfeit medicines (such as oxycodone®).

Effects of fentanyl

There is no safe level of drug use. Use of any drug always carries some risk. It’s important to be careful when taking any type of drug.

Fentanyl affects 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 between drug form e.g. patches, lozenges or injection).

Its effects may include:

  • euphoria
  • relief from pain
  • nausea, vomiting
  • constipation and/or diarrhea
  • reduced appetite
  • wind, indigestion, cramps
  • drowsiness, confusion
  • weakness or fatigue
  • dizziness
  • headache
  • incoherent or slurred speech
  • impaired balance
  • slow pulse and lowered blood pressure
  • rash (inflammation, itch, swelling at patch site).1, 4


If the dose is too high, you might overdose. Call an ambulance straight away by dialling triple zero (000) if you have any of these symptoms (ambulance officers do not have to involve the police):

  • chest pain
  • slowed breathing
  • bluish lips and complexion
  • seizure
  • passing out
  • coma
  • death.1,5

In the case of an overdose, Naloxone (also known as Narcan®) reverses the effects of opiates (including fentanyl).

Naloxone, is available over the counter and, is available either as a fast-acting nasal spray or a preloaded multiple dose syringe.

It can be administered by health professionals, family or household members and peers.6 Speak with your chemist or pharmacist for more information.

If injecting drugs, there is an increased risk of:

  • tetanus.
  • infection.
  • vein damage.

If sharing needles, there is an increased risk of:

  • hepatitis B.
  • hepatitis C.
  • HIV and AIDS.

Long-term effects

Regular use of fentanyl may cause:

  • mood instability
  • reduced libido
  • constipation
  • menstrual problems
  • respiratory impairment.3

Using fentanyl with other drugs

The effects of taking fentanyl with other drugs – including over-the-counter or prescribed medications – can be unpredictable and dangerous, and could cause:

Fentanyl + alcohol: adds to adverse effects and may increase the risk of respiratory depression.

Fentanyl + monoamine oxidase inhibitors (MAOI) antidepressants: may result in severe unpredictable reactions. MAOI were the first type of antidepressants developed but generally have been replaced by ones that are safer and have less side effects. Read more here.

Fentanyl + benzodiazepines: may add to the sedative effects and diminished breathing.1

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.



Giving up fentanyl 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 12 hours after the last dose and can last for about a week. Days one to three will be the worst. Symptoms include:

  • goose flesh/bumps
  • bouts of chills alternating with bouts of flushing and excessive sweating
  • irritability
  • insomnia
  • loss of appetite
  • yawning and sneezing
  • watery eyes and runny nose
  • vomiting and nausea
  • diarrhea
  • increased heart rate and blood pressure
  • pains in the bones and muscle
  • general weakness
  • depression.3


Not sure what you are looking for?
Try our intuitive Path2Help tool and be matched with support information and services tailored to you.

Find out more
Image of a woman walking through a maze


In Australia between 2000-2011, one hundred and thirty-six fentanyl-related deaths were recorded.

54% had a history of injecting drug use and 95% had injected fentanyl at the time of death.

Deaths were primarily among Australians aged under 47 years.7

Safe storage and disposal

Fentanyl patches should be stored at room temperature, away from excess heat and moisture (not in the bathroom). To dispose of used fentanyl patches, fold the patch inwards on itself so that the adhesive sides meet, and return to the dispensing pharmacy. Wash your hands thoroughly with soap and water after disposing of the fentanyl patches. Do not put leftover or used fentanyl patches in the rubbish.2,8

  1. Upfal J. The Australian drug guide. 7th ed. Melbourne Black Inc.; 2006.
  2. NPS MedicineWise. Fentanyl Sandoz.: NPS MedicineWise; 2020. [Accessed 27 November 2020]
  3. Brands B, Sproule B, & Marshman J. Drugs & Drug Abuse. 3rd ed. Ontario: Addiction Research Foundation; 1998.
  4. Darke S, Lappin, J, & Farrell, M. The Clinician's Guide to Illicit Drugs. United Kingdom: Silverback Publishing 2019.
  5. Medline Plus. Fentanyl Transdermal Patch: U.S. Department of Health and Human Services; 2020 [Accessed 27 November 2020].
  6. NPS MedicineWise. Naloxone nasal spray (Nyxoid) for opioid overdose: NPS MedicineWise; 2020. [Accessed 27 November 2020].
  7. Roxburgh A Burns L Drummer O Pilgrim J Farrell M & Degenhardt L. Trends in fentanyl prescriptions and fentanyl‐related mortality in Australia. Drug and alcohol review. 2013;32(3):269-75.
  8. NPS MedicineWise. Accidental fentanyl exposure in children can be fatal: NPS MedicineWise; 2015.

Explore opioids on the Drug Wheel

Drug wheel segment - Opioids segment@2x.png


constipation, cramps, diarrhoea, dizziness, euphoria, fatigue, headache, impaired balance, indigestion, low blood pressure, nausea, rash, reduced appetite, relief from pain, skin rashes, slurred speech, treat severe pain, vomiting, weakness, wind