Fentanyl for pain relief

About fentanyl

What is fentanyl used for?

Fentanyl is a strong opioid painkiller that is used to treat severe or chronic pain.

If you have long-term (chronic) pain, you may be prescribed a fentanyl skin patch. This is called transdermal fentanyl. The patch releases fentanyl slowly over time to give continuous pain relief.

Sometimes, pain may still break through. This is called breakthrough pain. In these cases, fentanyl may be given in other forms, such as lozenges, tablets, films, or nasal sprays, which are taken when needed for fast pain relief.

Fentanyl can also be given as an injection during surgery to help control pain.

How does fentanyl work?

It works by binding to certain tiny areas, called opioid receptors, in your brain and spinal cord (central nervous system). This leads to a decrease in the way you feel pain and your reaction to pain.

Side effects of fentanyl

Common side effects of fentanyl include:

• Constipation.

• Feeling sick.

• Being sick (vomiting).

• Feeling dizzy.

• Feeling sleepy or tired.

• Breathing problems.

• Headache.

• Stomach (tummy) pain.

You will find a full list in the manufacturer's information leaflet supplied with your medicine.

The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any side effects continue or become troublesome.

How to manage fentanyl side effects

If you experience other symptoms which you think may be due to fentanyl, speak with your doctor or pharmacist for further advice.

Who should not take fentanyl?

Some medicines are not suitable for people with certain conditions. Before taking fentanyl it is important that your doctor knows:

• If you are pregnant or breastfeeding.

• If you have a problem with the way your liver works, or a problem with the way your kidneys work.

• If you have a sore mouth or diabetes. This is because some brands of fentanyl may not be suitable for you to take.

• If you have prostate problems or any difficulties passing urine.

• If you have any breathing problems, such as asthma or chronic obstructive pulmonary disease (COPD).

• If you have been told you have low blood pressure.

• If you have any problems with your thyroid or adrenal glands.

• If you have epilepsy.

• If you have a problem with your bile duct.

• If you have been constipated for more than a week or have an inflammatory bowel problem.

• If you have a condition causing muscle weakness, called myasthenia gravis.

• If you have recently had a severe head injury, or have a brain tumour.

• If you have ever been dependent on drugs or alcohol.

• If you have ever had an allergic reaction to a medicine.

• If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

How to use fentanyl

• Use fentanyl exactly as prescribed by your doctor.

• Fentanyl comes in different forms, so your doctor or pharmacist will explain how to use yours.

• When you first start fentanyl, your dose is usually increased gradually to find the right level for your pain and reduce side effects.

• Once the correct dose is found, keep using the same dose unless your doctor tells you to change it.

• Check the label on the pack for your dose and follow the instructions carefully.

• If you are unsure about the dose or how to use it, ask your pharmacist for advice.

If you are using fentanyl patches

• Open the pouch carefully and check the patch is not damaged. Keep the pouch to safely dispose of the patch later.

• Apply to clean, dry, healthy skin on your upper arm or upper body. Press firmly for about 30 seconds, especially around the edges. Avoid touching the sticky side. Wash your hands after applying.

• It may take up to 24 hours for the patch to reach full effect, so you may need other pain relief during this time.

• Leave the patch on for 72 hours (3 days). After this, remove it and apply a new patch to a different area. Change it at the same time of day each time.

• Dispose of used patches safely: fold it sticky side inwards, put it in the pouch, and follow your doctor’s instructions. Keep out of reach of children.

• Avoid heat sources on the patch, such as heating pads, hot water bottles, electric blankets, heated water beds, long hot baths, saunas, or sunbathing. Heat can release too much fentanyl and increase the risk of overdose.

• Tell your doctor if you develop a high temperature, as this can also increase fentanyl absorption.

• Always check your brand when getting a new prescription. Different brands may release fentanyl differently; stick to the same brand unless your doctor advises otherwise.

• Watch for signs of too much fentanyl: shallow or weak breathing, extreme sleepiness, confusion, slurred speech, or severe dizziness. If these happen, remove the patch and contact your doctor immediately.

If you are using fentanyl lozenges (Actiq®)

• Use the applicator to move the lozenge around your mouth while you suck it. Let it touch your tongue and inside of your cheeks.

• Do not chew or swallow the lozenge. Fentanyl is absorbed through the lining of your mouth.

• If your mouth is dry, moisten it with water before using the lozenge.

• Suck one lozenge over about 15 minutes.

• If your pain has not eased within 15 minutes after finishing the lozenge, you may suck another one.

• Do not use more than two lozenges for one episode of pain, or more than four in 24 hours.

• If your pain is not controlled, tell your doctor.

If you are using fentanyl sublingual tablets (Abstral®)

• Place the tablet under your tongue and let it dissolve completely.

• Do not chew, suck, or swallow the tablet.

• You can moisten your mouth with water before use, but do not eat or drink while it is dissolving.

• If your pain hasn’t eased in 15-30 minutes, you may use one more tablet.

• Do not use more than two tablets for one episode of pain.

• Wait at least 2 hours before treating a new episode of breakthrough pain.

• If you have more than four episodes of breakthrough pain in 24 hours, tell your doctor.

• If pain is still not controlled, contact your doctor.

If you are using fentanyl buccal tablets (Effentora®)

• Place the tablet between your gum and cheek and let it dissolve completely.

• Do not chew, suck, or swallow the tablet.

• You can moisten your mouth with water before use, but do not eat or drink while it is dissolving.

• If after 30 minutes small pieces remain, you can swallow them with water.

• If pain hasn’t eased in 30 minutes, you may use another tablet on the other side of your mouth or under your tongue.

• Do not use more than two tablets for one episode of pain.

• Wait at least 4 hours before treating another episode of breakthrough pain.

• If pain is still not controlled, contact your doctor.

If you are using fentanyl nasal spray (PecFent®)

• Sit or stand while using the spray.

• Bend your head slightly forward and hold the spray upright.

• Close one nostril with a finger and insert the tip into the other nostril.

• Spray once while breathing in through your nose.

• If pain hasn’t eased in 10 minutes, use a second spray in the other nostril.

• Do not use more than two sprays for one episode of pain.

• Wait at least 4 hours before treating another episode.

• If pain is not controlled, or if you have more than four episodes of breakthrough pain in 24 hours, contact your doctor.

Getting the most from your treatment

• Do not drink alcohol while taking fentanyl. Alcohol can increase side effects like dizziness and sleepiness.

• Fentanyl is only given for as long as needed. Long-term use can cause tolerance (the medicine works less) and dependence, which may lead to withdrawal symptoms if it is stopped suddenly. Your doctor will reduce your dose gradually when it’s no longer needed.

• Fentanyl can slow your reactions. Do not drive if you feel drowsy or dizzy. Even if you feel safe, carry proof that fentanyl is prescribed (such as prescription slip or patient leaflet).

• Tell your doctor, dentist, or other healthcare professional that you are taking fentanyl before having any procedures or dental treatment.

• Before taking other medicines check with a pharmacist that they are safe to take with fentanyl.

• Fentanyl is a controlled drug, so carry a letter from your doctor when travelling. For trips longer than three months, you must apply to the Home Office for a licence to take fentanyl with you.

How to store fentanyl

• Keep all medicines out of the reach and sight of children. This includes used patches and part-finished lozenges.

• Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Frequently asked questions

How long does it take for fentanyl to work?

Fentanyl usually starts to work within minutes, although the exact timing depends on how it is taken. Injected fentanyl works in 1-5 minutes, lozenges or nasal sprays in 5-15 minutes, and fentanyl patches begin providing pain relief after 12-24 hours.

How long does fentanyl stay in your system?

Fentanyl can stay in your system for 1 to 3 days, depending on dose and method of use. It is typically detectable for up to 24 hours in blood, 1-3 days in urine, 48 hours in saliva, and up to 90 days in hair. Fentanyl patches may cause longer-lasting effects.

Is fentanyl addictive?

Yes, fentanyl is highly addictive, even when prescribed. It is a strong opioid painkiller that can cause physical dependence, tolerance, and opioid addiction, particularly with long-term or non-medical use.

Is fentanyl stronger than morphine?

Yes, fentanyl is much stronger than morphine. It is around 50 to 100 times more potent, meaning much smaller doses are needed to achieve the same level of pain relief.

What happens when you stop taking fentanyl?

Stopping fentanyl suddenly can cause withdrawal symptoms. Common symptoms include muscle aches, anxiety, sweating, feeling sick, diarrhoea, and sleep problems. Doctors usually recommend gradually reducing the dose to minimise withdrawal.