Experiences with
FentanylFentanyl is a strong opioid painkiller. It's used to treat severe pain, for example during or after an operation or a serious injury, or pain from cancer.
It's also used for other types of long-term pain when weaker painkillers have stopped working.
It works by blocking pain signals between the brain and the rest of the body. It also reduces the anxiety and stress caused by pain.
Fentanyl is only available on prescription. It comes as:
- patches to put on your skin
- lozenges and tablets that dissolve in your mouth
- nasal spray
- injections – usually only given in hospital
Fentanyl patches are used for long-lasting pain. Your doctor may also prescribe other types of fentanyl if you need extra pain relief while your regular painkiller wears off.
Who can use fentanyl
Most adults can use fentanyl.
Some patches can be used by children aged 2 years old and over. However, young children and older people are more likely to get side effects.
Fentanyl patches are usually only used if you've already been taking other strong opioid painkillers.
Your doctor will work out how much fentanyl to give you depending on what dose of other opioids you've been taking. This is to reduce the risk of an overdose.
Who may not be able to use fentanyl
Fentanyl is not suitable for some people. To make sure it's safe for you, tell your doctor if you:
- are not already regularly using strong opioid painkillers
- have ever had an allergic reaction to fentanyl or any other medicine
- have breathing difficulties such as asthma or a lung condition
- are addicted to alcohol or are a heavy drinker
- have a head injury
- have a condition that causes fits or seizures
- have an irregular heartbeat (arrhythmia)
- have adrenal gland problems
- have kidney or liver problems
- have an enlarged prostate
- have low blood pressure (hypotension)
- are trying to get pregnant, are already pregnant or breastfeeding
Dosage and strength
Fentanyl comes in different strengths, depending on the type:
- Patches release 12 micrograms to 100 micrograms of fentanyl every hour.
- Nasal spray contains 50 micrograms to 400 micrograms.
- Tablets contain 100 micrograms to 800 micrograms.
- Lozenges contain 200 micrograms to 1,600 micrograms.
Doses vary from person to person. Your dose will depend on:
- how bad your pain is
- how you've responded to other painkillers
- if you get any side effects from fentanyl
Changes to your dose
Before taking or using fentanyl, you'll usually start on a low dose of another type of opioid, such as morphine. This will be increased slowly until your pain is well controlled.
Once your pain is under control, your doctor may swap you to fentanyl patches. This will avoid you having to take tablets or capsules each day.
If your doctor agrees that you can stop taking fentanyl, they'll reduce the strength of your patch gradually. This is especially important if you've been taking it for a long time to reduce the risk of withdrawal symptoms.
Your doctor may switch you to morphine tablets, liquid or another similar painkiller so they can reduce the dose even more slowly.
How to take or use it
How often you take or use fentanyl depends on the type you've been prescribed.
Patches
Apply a new patch every 3 days. Always remove the old one first.
Sometimes your doctor may prescribe a fentanyl patch with a fast-acting painkiller. This is to manage sudden flare-ups of pain that break through the relief the patches give.
Do not apply more than 1 patch at a time, unless your doctor tells you to. Using more patches than recommended could lead to a fatal overdose.
Do not let your patch stick to someone else's skin, especially a child's, by mistake.
Do not pass your patch on to anybody else. It must only be used by the person it has been prescribed for.
- Read the instructions that come with your patch carefully.
- Remove the patch from the packet. Do not cut fentanyl patches.
- Keep the empty packet – you'll need to put your used patch in this to keep it safe. You'll then need to return it to your pharmacist who will destroy it in the right way.
- Peel off the plastic from the back of the patch. Do not touch the sticky side of the patch.
- Apply the patch to clean, dry, flat, undamaged skin. Do not touch the sticky side of the patch. Choose somewhere you can reach easily such as the top of your chest or top of your arm. Try to avoid very hairy areas, or trim the hairs first before applying the patch. If you find shaving easier, shave the area a few days before you apply the patch to make sure shaving does not irritate your skin. If you're applying the patch to a young child, put it on their upper back so they cannot reach it.
- Press the patch against your skin for at least 30 seconds. Make sure it sticks well, especially the edges.
- If your doctor tells you to use more than 1 patch, follow the instructions that come with the patches. Do not let the patches overlap on your skin.
- Do not cover the patch or patches with anything, including a dressing or tape. Talk to your doctor or pharmacist if you find your patch does not stick very well.
- Wash your hands after touching a patch.
Do not expose your patch to strong heat or sunlight. This can increase the amount of fentanyl that gets absorbed into your skin and can increase the risk of side effects or overdose. This includes long hot baths, saunas, electric blankets, hot water bottles, heat pads and sunbathing.
You can have showers and go swimming. Check the patch is still on properly afterwards and dry the area around the patch carefully.
Changing your patch
When you change your patch, try to do it at the same time of day. Think of ways to help you remember when to change it. You could:
- write the details on your calendar
- write the time and date on the surface of the patch itself (using a soft-tip, permanent marker pen)
- use a phone app or smart speaker to record the time
Take off the old patch and fold it firmly in half so the sticky side sticks to itself. Put it back in its original packet and dispose of the packet as instructed by your pharmacist.
Keep used patches out of sight and reach of children. Even used patches contain some medicine that may harm children and may even be fatal.
After you've taken off the old patch, apply the new patch to a different area of skin.
If your patch falls off
Check your patch every day to make sure it stays stuck to you, especially around the edges.
If your patch is missing, make sure it has not stuck to someone else's skin, especially a child's, by mistake – for example if it falls off in bed or if the patch falls on the floor.
It's important to find it and put it back in the packet until you can return it to your pharmacist.
If a patch falls off before the usual 3 days are up, put another patch on a different part of your body and put the old patch back in the packet it came in. Make a note of the day and time. Then change the patch again after a further 3 days as usual.
- a fentanyl patch sticks to someone it has not been prescribed for
If this happens, remove the patch straight away.
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the fentanyl packet or leaflet inside it, any remaining medicine, and any other medicines you take.
You'll usually only use fentanyl tablets, lozenges or nasal spray when you need them. Tell your doctor if you need to use them more than 4 times a day.
How to take fentanyl tablets
- Read the instructions that come with your tablets carefully. This will tell you how to remove the tablet from the packaging, and where to put the tablet in your mouth.
- If you have a dry mouth, you can use some water to wet your mouth first.
- Put the tablet in your mouth, either under your tongue, or between your cheek and gum depending on the type of tablet you have.
- Let the tablet melt in your mouth without sucking or chewing it.
- you begin to feel dizzy, sick or very sleepy before the tablet has finished melting
If this happens, take the tablet out of your mouth straight away. Rinse your mouth with water and spit any remaining pieces of the tablet into a sink or toilet.
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the fentanyl packet or leaflet inside it, any remaining medicine, and any other medicines you take.
Talk to your doctor about reducing the dose if you get these side effects.
How to take fentanyl lozenges
- Read the instructions that come with your lozenges carefully.
- If you have a dry mouth you can use some water to wet your mouth first.
- Hold the handle and put the lozenge in your mouth against your cheek.
- Keep moving the lozenge around in your mouth, especially along your cheeks, and twirl the handle.
- Do not bite or chew the lozenge, and try not to finish it too quickly. It should take about 15 minutes to melt.
- you begin to feel dizzy, sick or very sleepy before the lozenge is finished
If this happens, take the lozenge out of your mouth straight away. Rinse your mouth with water and spit any remaining pieces of the lozenge into a sink or toilet.
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the fentanyl packet or leaflet inside it, any remaining medicine, and any other medicines you take.
Talk to your doctor about reducing the dose if you get these side effects.
How to use fentanyl nasal spray
- Read the instructions that come with your nasal spray carefully. This will tell you how to use the nasal spray that you have.
- Sit down with your head upright.
- Blow your nose if you need to.
- Close 1 nostril by pressing the outside of your nose with your finger.
- Spray 1 dose into the other nostril.
- If your doctor has told you that you can use a 2nd dose, use the opposite nostril this time.
How long to use fentanyl for
Depending on why you're using fentanyl, you may only need to use it for a short time.
For example, if you're in pain after an injury or operation, you may only need to use fentanyl for a few days or weeks.
You may need to use it for longer if you have a long-term condition.
Storing fentanyl safely
Keep all types of fentanyl in a safe place and out of reach of children or vulnerable adults.
Used patches still contain fentanyl that can be dangerous to someone else. It's important to stick the sticky sides back together after you've taken them off and keep them safe until you can take them back to your pharmacist.
If you forget to use it
What to do if you forget to take or apply fentanyl depends on which type you're using. Most types of fentanyl are only taken when you need them and so you're unlikely to forget.
Never take 2 doses at the same time. Never have an extra dose to make up for a forgotten one.
If you forget to change your patch, do it as soon as you remember and make a note of the day and time. Then change the patch again after 3 days as usual. If you're very late changing your patch, do not apply a new patch without talking to your doctor first.
Always remove the old patch before applying a new one. Never use more than 1 patch at a time, unless your doctor tells you to.
If you often forget to change patches, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicines.
If you take or use too much
It's important not to take more than your prescribed dose, even if you think it's not enough to relieve your pain. Speak to your doctor first if you think you need a different dose.
Too much fentanyl can be dangerous. However, the amount that can lead to an overdose varies from person to person.
If you've taken too much you may feel very sleepy, sick or dizzy. You may also find it difficult to breathe. In serious cases you can become unconscious and may need emergency treatment in hospital.
- you've taken more than your prescribed dose of fentanyl and you have difficulty breathing, start to lose consciousness or feel sleepy, sick or dizzy
- you or someone else swallows a fentanyl patch
- you've taken more than your prescribed dose of fentanyl, even if you do not have symptoms
Go to 111.nhs.uk or call 111 . Call 111 if you're asking about a child under the age of 5 years.
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the fentanyl packet or leaflet inside it, any remaining medicine, and any other medicines you take.
If you need to take or use fentanyl for a long time your body can become used to it.
This is not usually a problem. However, you could get withdrawal symptoms if you stop using it suddenly.
If you want to stop using fentanyl, talk to your doctor first. Your dose can be reduced gradually so you do not get withdrawal symptoms.
If you stop using fentanyl suddenly it can make you:
- feel agitated
- feel anxious
- shaky
- sweat a lot
If you've been taking or using fentanyl for more than a few weeks, do not stop without speaking to your doctor first.
Common side effects
These common side effects of fentanyl happen in more than 1 in 100 people. There are things you can do to help cope with them:
Get more fibre into your diet such as fresh fruit, vegetables and cereals, and drink plenty of water. If you can, it may also help to do some gentle exercise. If this does not help, talk to your pharmacist or doctor.
It's likely you'll need to take a laxative to help prevent or treat constipation caused by fentanyl. Ask your doctor if you're not taking a laxative or if your constipation symptoms do not go away.
This side effect should normally wear off after a few days. Stick to simple meals and do not eat rich or spicy food.
If you're being sick, try small frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.
Ask your doctor about anti-sickness medicine if it gets worse or lasts longer than a few days.
If you take the combined contraceptive pill or the progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals.
Putting a heat pad or covered hot water bottle on your stomach may also help. But do not do this if it would be near to your fentanyl patch. Patches should not be exposed to heat.
If you're in a lot of pain, speak to your pharmacist or doctor.
These side effects should wear off within a week or 2 as your body gets used to fentanyl. Talk to your doctor if they carry on for longer.
Do not drink alcohol as it will make these side effects worse. Do not drive, ride a bike or use tools or machinery.
Stop what you're doing and sit or lie down until you feel better. Do not drink alcohol as it will make these side effects worse.
If the feeling does not go away, do not take any more medicine and speak to a pharmacist or your doctor.
Do not drive, ride a bike or use tools or machinery.
Talk to your doctor if you feel confused. Your dose may need to be changed.
Make sure you rest and drink plenty of fluids. Do not drink alcohol while taking fentanyl as this can make headaches worse. Ask your pharmacist to recommend a painkiller.
Headaches should usually go away after the first week of taking fentanyl. Talk to your doctor if they last longer than a week or are severe.
It may help to take an antihistamine, which you can buy from a pharmacy. However, some types of antihistamine may not be suitable to take with fentanyl. Check with the pharmacist to see what type is suitable for you.
If symptoms do not go away or it gets worse talk to your doctor as you may need to try a different painkiller.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Serious side effects happen in less than 1 in 100 people.
Call a doctor or call 111 now (and remove a patch if you're wearing one) if:
- your muscles feel stiff for no obvious reason
- you feel dizzy, tired or have low energy – these could be a sign of low blood pressure
- you have difficulty breathing or have short shallow breathing
- you've had a fit or seizure
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to fentanyl.
Meds New IA (H4) - serious allergic reactionSome people with conditions that need long-term pain relief may need to take fentanyl for a long time.
If you need to take it for a long time your body can become used to it (known as tolerance). That means you need higher doses to control your pain over time.
Some people can become more sensitive to pain (hyperalgesia). If this happens, your doctor will reduce your dose gradually to help these symptoms.
It's possible to become addicted to fentanyl. For this reason, your dose will be reviewed to make sure you're only having the amount you need to control your pain.
Your treatment plan may include details of how and when you'll stop fentanyl.
If you're having treatment for cancer pain or other severe pain, your pain control will be carefully monitored. Speak to your doctor if you're worried about tolerance, hyperalgesia or becoming addicted.
Other side effects
These are not all the side effects of fentanyl. For the full list, see the leaflet inside you medicines packet.
Fentanyl and pregnancy
Fentanyl may occasionally be used for pain that is severe or difficult to treat during pregnancy.
If you take fentanyl towards the end of pregnancy your baby might have withdrawal symptoms, such as drowsiness, after they're born. Your baby may need extra time in hospital for observation.
It's important to treat pain in pregnancy. For some pregnant women with pain that lasts a long time or is difficult to treat, fentanyl might be the best option. Your doctor is the best person to help you decide what's right for you and your baby.
Fentanyl and breastfeeding
Fentanyl can be used if you're breastfeeding. It's important that your pain is controlled.
Only very small amounts of fentanyl pass into breast milk, but there's still a small risk that it may cause side effects in your baby. Your doctor may recommend different painkillers first.
If you do take fentanyl while breastfeeding, it's best to take it in low doses and only for a short time if possible. This reduces the risk of your baby getting side effects.
It's also important not to stop breastfeeding suddenly so your baby does not get withdrawal symptoms.
Talk to your doctor, pharmacist, health visitor or midwife as soon as possible if you have any concerns about your baby, including if you notice your baby:
- is not feeding as well as usual
- has constipation
- seems unusually pale
- your baby is unusually sleepy
- your baby has breathing problems
However, these effects are very rare.
If you need to go to A&E, take the fentanyl packet or leaflet inside it, plus any remaining medicine, with you.
Fentanyl and fertility
There's no evidence that fentanyl affects fertility in either men or women.
Speak to a pharmacist or your doctor if you're trying to get pregnant. They may want to review your treatment.
Meds New IA (H2) - Pregnancy non-urgent care cardCautions with other medicines
There are some medicines that may affect how fentanyl works and increase the chance that you'll have side effects.
Tell your doctor if you're taking any medicines:
- to help you sleep
- for high blood pressure
- for an irregular heartbeat
- to help stop you feeling or being sick
- to treat symptoms of an allergy
- for mental health problems including depression, or to reduce stress or anxiety
- for any infection (including HIV)
- to control fits or seizures
Taking fentanyl with other painkillers
It's safe to take fentanyl with paracetamol, ibuprofen or aspirin.
Do not take any painkillers containing codeine including co-codamol, ibuprofen and codeine (Nurofen Plus) or Solpadeine when using fentanyl. You'll be more likely to get side effects if you take any of these while using fentanyl.
Mixing fentanyl with herbal remedies and supplements
There's not enough information to say that complementary medicines and herbal remedies are safe to take with fentanyl. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.
Meds New IA (H2) - Cautions with other medicines alertRelated links
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