What is fentanyl?

Fentanyl is a strong opioid medicine that can be prescribed by your doctor as part of a broader strategy to help manage your pain.

What is fentanyl used for?

Fentanyl is used to treat acute pain caused by major trauma or surgery, as well as chronic pain caused by cancer.

How long you need to take fentanyl for will depend on why it has been prescribed. For example, fentanyl patches for cancer pain or in people receiving palliative care are approved for life-long use, while fentanyl used in acute pain or anaesthesia will be used only for a short time.

How does fentanyl work?

Fentanyl works directly on opioid receptors in the central nervous system and reduces feelings of pain by interrupting the way nerves signal pain between the brain and the body.

It is available in several formulations in different strengths, including patches, lozenges, tablets that disintegrate in your mouth and sublingual (under the tongue) tablets. Fentanyl is also given by injection for severe acute pain or as part of anaesthesia before surgery.

What are the possible side effects of taking fentanyl?

All opioids, including fentanyl, can have side effects including life-threatening breathing problems — the risk of these is higher:

• when first taking fentanyl
• after a dosage increase
• if you are older
• if you have an existing lung problem

Fentanyl affects everyone differently, so if you have any of these side effects while taking fentanyl, or if you notice anything that is making you feel unwell, speak with your pharmacist or doctor.

The side effects of fentanyl are similar to those of other opioids, and include:

• drowsiness, confusion, dizziness
• nausea, vomiting, wind, cramps
• constipation, diarrhoea
• rash (inflammation, itch, swelling at patch site)
• weakness, fatigue
• headache
• incoherent, slurred speech
• balance problems

Always take medicines exactly as your doctor prescribes, and as directed by your pharmacist.

What are the risks associated with fentanyl?

Opioids are strong pain medicines and can cause life-threatening or fatal breathing difficulties.

Your doctor will monitor how you use fentanyl to reduce your risk of harm, including through misuse or abuse.

You can also develop tolerance when you take fentanyl — this means that you may need to take larger amounts of the opioid to get the same effect. As the dosage increases, so does the risk of side effects.

Continue to take fentanyl for as long as your doctor tells you to. Suddenly stopping fentanyl can cause withdrawal symptoms.

Fentanyl may make it difficult for you to drive or operate heavy machinery. If you have recently started taking an opioid medication or changed dosage, you may be at higher risk of having an accident.

If your kidney or liver function is impaired, your doctor may decide that fentanyl is not appropriate for you. There are also other factors that may limit your use of fentanyl — for example, if you drink alcohol or take other medicines that can cause drowsiness.

Your doctor is the best person to guide you on whether fentanyl is the right medicine for you, how much you need and how long to take it for.

If a person is not breathing, or if they are unresponsive, seek help straight away. Call triple zero (000) and ask for an ambulance.

Are there any alternatives to fentanyl?

Different pain relief medicines are used in different circumstances. If you have been prescribed fentanyl and are still in pain, speak with your doctor about other ways you can manage your pain.

If you have chronic (long-term) pain, your doctor might suggest lifestyle changes to help manage the discomfort. These might include physical fitness and activity pacing, social activities, relaxation techniques and overall health management.

You can find more information here about options for managing chronic pain.

When should I see my doctor?

If your pain is not well controlled on fentanyl or you have any unexpected side effects, see your doctor. Do not adjust your fentanyl dosage without talking to your doctor first.

How do I dispose of medicines safely?

It's important you dispose of unwanted opioid medicines safely — unused medicines can be returned to any pharmacy. Don't keep unused medicines 'just in case' since this can lead to inappropriate use.

Dispose of a used fentanyl patch by folding it over on itself (bringing the adhesive sides together).

Keep fentanyl out of reach of children and pets. Never throw medicines into a garbage bin or flush them down the toilet since this is dangerous to others and harmful to the environment.

Resources and support

Asking about your treatment or medication is important to help you understand your options. Here's a guide to questions to ask your pharmacist or doctor before taking a medicine.

See also this list of medicines that contain fentanyl to read the consumer medicine information (CMI) leaflet for the brand prescribed, or:

• Call 1300 MEDICINE (1300 633 424) to talk about the medicines you are taking for your pain.


• Discuss your pain on the Pain Link telephone helpline (1300 340 357) which is staffed by volunteers with personal experience of chronic pain.


• Got to Painaustralia to find pain services and programs in your area.


• Learn more about prescription opioids on the Choosing Wisely website.