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How and when to use fentanyl

Follow your doctor's instructions about how to use this medicine. This is particularly important because fentanyl can be addictive.

Fentanyl tablets, lozenges, nasal spray and injections work quickly. They're used for pain that is expected to last for a short time.

Fentanyl patches are slow-release. This means fentanyl is gradually released through the skin into your body. They take longer to start working but last longer. They're used for pain that lasts a long time.

Some patches keep working after they've been removed as they store fentanyl under the skin.

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.

Important: Overdose warning

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.

How to apply a fentanyl patch

  1. Read the instructions that come with your patch carefully.
  2. Remove the patch from the packet. Do not cut fentanyl patches.
  3. 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.
  4. Peel off the plastic from the back of the patch. Do not touch the sticky side of the patch.
  5. 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.
  6. Press the patch against your skin for at least 30 seconds. Make sure it sticks well, especially the edges.
  7. 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.
  8. 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.
  9. 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.

Urgent advice: Call your doctor or call 111 now if:
  • 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 yourself. Get someone else to drive you or call for an ambulance.

Take the fentanyl packet, or the leaflet inside it, with you.

Tablets, lozenges and nasal spray

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

  1. 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.
  2. If you have a dry mouth, you can use some water to wet your mouth first.
  3. Put the tablet in your mouth, either under your tongue, or between your cheek and gum depending on the type of tablet you have.
  4. Let the tablet melt in your mouth without sucking or chewing it.
Urgent advice: Call your doctor or call 111 now if:
  • 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 yourself. Get someone else to drive you or call for an ambulance.

Take the fentanyl packet, or the leaflet inside it, plus any remaining medicine with you.

Talk to your doctor about reducing the dose if you get these side effects.

How to take fentanyl lozenges

  1. Read the instructions that come with your lozenges carefully.
  2. If you have a dry mouth you can use some water to wet your mouth first.
  3. Hold the handle and put the lozenge in your mouth against your cheek.
  4. Keep moving the lozenge around in your mouth, especially along your cheeks, and twirl the handle.
  5. Do not bite or chew the lozenge, and try not to finish it too quickly. It should take about 15 minutes to melt.
Urgent advice: Call your doctor or call 111 now if:
  • 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 yourself. Get someone else to drive you or call for an ambulance.

Take the fentanyl packet, or the leaflet inside it, plus any remaining medicine with you.

Talk to your doctor about reducing the dose if you get these side effects.

How to use fentanyl nasal spray

  1. Read the instructions that come with your nasal spray carefully. This will tell you how to use the nasal spray that you have.
  2. Sit down with your head upright.
  3. Blow your nose if you need to.
  4. Close 1 nostril by pressing the outside of your nose with your finger.
  5. Spray 1 dose into the other nostril.
  6. 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.

Immediate action required: Call 999 or go to A&E now if:

  • 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

Urgent advice: Contact 111 for advice now if:

  • 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 yourself. Get someone else to drive you or call for an ambulance.

Take the fentanyl packet, or the leaflet inside it, plus any remaining medicine with you.

Stopping fentanyl

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

Important

If you've been taking or using fentanyl for more than a few weeks, do not stop without speaking to your doctor first.

Page last reviewed: 23 May 2023
Next review due: 23 May 2026