Fentanyl | Side Effects, Dosage, Uses & More
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Generic Name:

fentanyl, Sublingual/Translingual spray

All Brands

  • SUBSYS
SECTION 1 of 5

Highlights for fentanyl

Sublingual/Translingual spray
1

Fentanyl is available as a transdermal patch, buccal tablet, sublingual tablet, lozenge, sublingual spray, and nasal solution, spray.

2

Fentanyl sublingual spray is available as the brand-name drug Subsys. It isn’t available as a generic drug.

3

Do not use fentanyl if you’re not opioid tolerant. Opioid tolerant means that you currently take another opioid pain drug that no longer works as well to control your pain.

4

Do not use fentanyl for short-term pain, such as pain after surgery, headache or migraine, or pain from a dental procedure.

5

Fentanyl can cause serious breathing problems if doses are too high.

IMPORTANT INFORMATION

FDA warning

This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.

Addiction and abuse warning. This drug can lead to addiction and misuse, which can result in overdose and death. Because of the potential for misuse, abuse, and addiction, you may only obtain fentanyl by enrolling in Transmucosal Immediate Release Fentanyl (TIRF) Risk Evaluation and Mitigation Strategy (REMS) Access Program.

Decreased breathing rate warning. Fentanyl can decrease the rate at which you breathe. This can lead to breathing failure and possibly death. Your risk is higher if you are a senior, have lung disease, are given large initial doses, or if you use fentanyl with other medications that also affect your breathing pattern.

What is fentanyl?

Fentanyl is a prescription drug. It’s available in the following forms:

  • Transdermal patch. A patch that you place on your skin.
  • Buccal tablet. A tablet that you place between your cheek and gums, where it dissolves.
  • Sublingual tablet. A tablet that you place under your tongue, where it dissolves.
  • Sublingual spray. A solution that you spray under your tongue.
  • A lozenge that you suck on until it dissolves.
  • A solution that you spray in your nose.

This drug isn’t available as a generic drug.

Fentanyl may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Fentanyl is used for severe pain.

How it works

Fentanyl belongs to a class of drugs called opioid agonists.

More Details

How it works

Fentanyl belongs to a class of drugs called opioid agonists. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Fentanyl works in your brain to change how your body feels and responds to pain.

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SECTION 2 of 5

fentanyl Side Effects

Sublingual/Translingual spray

More Common Side Effects

Some of the more common side effects that can occur with use of fentanyl include:

  • fever, nausea, and vomiting

  • dizziness

  • insomnia

  • constipation

  • increased sweating

  • tiredness

  • feeling cold

  • headache

  • diarrhea

  • loss of appetite

  • drowsiness

  • low red blood cell count

  • swelling in your arms, hands, legs, and feet

  • weakness

  • anxiety

  • confusion

  • depression

  • rash

  • trouble sleeping

  • shortness of breath

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Serious breathing problems. Symptoms can include:

    • very shallow breathing (little chest movement with breathing)
    • fainting, dizziness, or confusion
  • Severely low blood pressure. Symptoms can include:

    • dizziness or lightheadedness especially if you stand up too quickly
  • Physical addiction, dependence, and withdrawal when stopping the drug. Symptoms can include:

    • restlessness
    • irritability or anxiousness
    • trouble sleeping
    • increase in your blood pressure
    • fast breathing rate
    • fast heart rate
    • dilated pupils of your eyes
    • teary eyes
    • runny nose
    • yawning
    • nausea, vomiting, and a loss of appetite
    • diarrhea and stomach cramps
    • sweating
    • chills or hairs on your arms “stand up”
    • muscle aches and backache
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Constipation (infrequent or hard bowel movements) is a very common side effect of fentanyl and is unlikely to go away without treatment. Talk to your doctor about dietary changes, laxatives (medicines that treat constipation), and stool softeners, which can prevent or treat constipation while taking fentanyl.

Fentanyl may cause drowsiness. Do not drive or operate heavy machinery until you know how fentanyl affects you.

After your first dose and when your doctor increases your doses of fentanyl, you may have a drop in blood pressure. Your doctor may have you check your blood pressure during these time periods.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

fentanyl May Interact with Other Medications

Sublingual/Translingual spray

Fentanyl can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Alcohol interaction

The use of drinks that contain alcohol can increase your risk of serious side effects from fentanyl. It may even result in coma or death. You should not drink alcohol while taking fentanyl.

Medications that might interact with this drug

Drugs you should not take with fentanyl
  • Do not take these drugs with fentanyl. Taking fentanyl with these drugs can cause dangerous effects in your body. Examples of these drugs include:
    • Buprenorphine
      • Taking this drug with fentanyl may lower the effect of fentanyl or cause withdrawal symptoms or both.
    • Depression drugs such as monoamine oxidase inhibitors (MAOIs)
      • Taking these drugs with fentanyl may cause anxiety, confusion, slowed breathing, or coma. Do not take fentanyl if you’re taking MAOIs or have taken MAOIs within the last 14 days.

Interactions that increase the risk of side effects
  • Taking fentanyl with certain medications may result in an increase in adverse effects. Examples of these drugs include:
    • Muscle relaxants, such as baclofen, cyclobenzaprine, and methocarbamol.
      • You may experience increased breathing problems.
  • Hypnotics, such as zolpidem, temazepam, and estazolam.
    • You may experience increased breathing problems, low blood pressure, extreme drowsiness, or coma. Your doctor may prescribe a lower dose for you.
  • Anticholinergic drugs, such as atropine, scopolamine, and benztropine.
    • You may experience increased problems urinating or severe constipation, which could lead to more serious bowel problems.
  • Voriconazole, ketoconazole.
    • These drugs may increase fentanyl levels in your body, which may increase your risk of side effects. Your doctor may monitor you more frequently and adjust your dose as necessary.
  • Erythromycin.
    • This medication may increase fentanyl levels in your body, which may increase your risk of side effects. Your doctor may monitor you more frequently and adjust your dose as necessary.
  • Ritonavir.
    • This medication may increase fentanyl levels in your body, which may increase your risk of side effects. Your doctor may monitor you more frequently and adjust your dose as necessary.

Interactions that can make drugs less effective
  • When fentanyl is used with certain drugs, it may not work as well to treat your condition. This is because the amount of fentanyl in your body may be decreased from the interaction with these drugs. Examples of these drugs include:
  • Rifampin.
    • This drug may decrease fentanyl levels in your body, making the fentanyl less effective in relieving your pain. Your doctor may monitor you more frequently and adjust your dose as necessary.
  • Carbamazepine, phenobarbital and phenytoin.
    • These drugs may decrease fentanyl levels in your body, making the fentanyl less effective in relieving your pain. Your doctor may monitor you more frequently and adjust your dose as necessary.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Drug warnings
breathing problems
People with breathing problems

Fentanyl may decrease your breathing rate. Use this medication with extreme caution if you’ve been diagnosed with a breathing problem, such as chronic obstructive pulmonary disease (COPD). Do not use fentanyl if you have asthma.

intestinal blockage and constipation
People with intestinal blockage and constipation

Fentanyl can cause you to not notice symptoms of these conditions. This can make it difficult for doctors to diagnose or find the cause of these conditions.

head injury or seizures
People with head injury or seizures

Fentanyl may cause increased pressure in your brain and cause breathing problems.

liver disease
People with liver disease

If you have liver disease, your body may process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects. Your doctor may start you on a lower dose. This can help keep levels of this drug from building up too much in your body.

kidney disease
People with kidney disease

If you have kidney disease or a history of kidney disease, you may not be able to clear this drug from your body well. This may increase the levels of fentanyl in your body and cause more side effects.

adrenal insufficiency
People with adrenal insufficiency

Taking this drug can reduce the amount of hormones your adrenal glands release. If you have this adrenal insufficiency, taking this drug can make it worse.

pancreas and gallbladder problems
People with pancreas and gallbladder problems

Taking this drug can cause spasms that can make symptoms of conditions such as biliary tract disease and pancreatitis worse.

urination problems
People with urination problems

Taking this drug can cause your body to retain urine. If you already have difficulty urinating, your doctor may prescribe a lowered dose.

slow heart rate
People with slow heart rate

Taking this drug can slow your heart rate. If you already have a slow heart rate (bradycardia), this drug can make it worse. Use fentanyl with caution. Your doctor may prescribe a lowered dose and monitor you more closely for side effects.

Pregnant women
Pregnant women

Fentanyl is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk to the fetus.

Using fentanyl for a long time during pregnancy can lead to withdrawal symptoms in your newborn child. Symptoms include irritability, overactive behaviors, abnormal sleep pattern, high-pitched crying, tremors, vomiting, diarrhea, and failure to gain weight.

breast-feeding
Women who are breast-feeding

Fentanyl does pass into breast milk and causes side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your baby. You may need to decide whether to stop breast-feeding or stop taking this medication.

for children
For children

The safety and effectiveness of this form of fentanyl hasn’t been established in people younger than 18 years.

call doctor
When to call the doctor

Call your doctor if you feel as though your pain remains uncontrolled. Your doctor may want to change the dose of your medicine.

allergies
Allergies

Fentanyl can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

SECTION 4 of 5

How to Take fentanyl (Dosage)

Sublingual/Translingual spray

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Severe, breakthrough cancer pain

Brand: Subsys

Form: Sublingual spray
Strengths: 100 micrograms, 200 micrograms, 400 micrograms, 600 micrograms, and 800 micrograms
Adult dosage (ages 18–64 years)
  • The starting dose is usually 100 micrograms. If you don’t feel relief 30 minutes after finishing your first spray, you may spray one more. You must wait at least 4 hours before taking another dose. Your doctor will work with you to increase the dose if your dose doesn’t relieve your pain.
  • Your doctor may increase your dose, based on your level of pain, up to a maximum dose of 1,600 micrograms. You must wait at least 4 hours between doses.
  • Spray the solution under your tongue.
Child dosage (ages 0–17 years)

The safety and effectiveness of this form of fentanyl hasn’t been established in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dose or a different medication schedule. This can help keep levels of this drug from building up too much in your body.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Fentanyl comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

If you don’t take it at all, you’ll continue to experience pain. If you stop taking the drug suddenly, you may experience symptoms of withdrawal, which can include:

  • restlessness
  • irritability or anxiousness
  • trouble sleeping
  • increase in your blood pressure
  • fast breathing rate
  • fast heart rate
  • dilated pupils of your eyes
  • teary eyes
  • runny nose
  • yawning
  • nausea, vomiting, and a loss of appetite
  • diarrhea and stomach cramps
  • sweating
  • chills or hairs on your arms “stand up”
  • muscle aches and backache

If you miss doses or don’t take the drug on schedule

Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • slowed breathing or changes in normal breathing pattern
  • difficulty speaking
  • confusion
  • irritability
  • extreme tiredness and drowsiness
  • cold and clammy skin
  • skin color turning blue
  • muscle weakness
  • pinpoint pupils
  • slow heart rate
  • dangerous heart problems
  • low blood pressure
  • coma

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room right away.

What to do if you miss a dose

Fentanyl should only be taken as needed. If you’re not feeling pain, you shouldn’t take a dose.

How to tell if the drug is working

You may be able to tell this medication is working if you feel less pain.

Fentanyl is used for short-term or long-term treatment, depending on your condition and the severity of your pain.

Store this drug carefully

  • Store fentanyl between 68°F and 77°F (20°C and 25°C). May travel with temperatures between 59°F and 86°F (15°C and 30°C) until ready to use.
  • Keep it in the original unopened pouch. Don’t use it if the blister package has been opened.
  • Keep it away from high temperatures.
  • Don’t store this medication in moist or damp areas, such as bathrooms.
  • Protect fentanyl from theft. Keep medicine in a locked cabinet or drawer.

A prescription for this medication is not refillable

You or your pharmacy will have to contact your doctor for a new prescription if you need this medication refilled.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

You doctor should monitor you while you take this drug. Things your doctor will check include:

  • Breathing rate. Your doctor will monitor for any changes in your breathing pattern, especially when you first start taking this drug and after any dose increases.
  • Blood pressure. Your doctor should check your blood pressure regularly.
  • Blood tests. Your doctor may have blood tests done to see how well your kidneys and liver are working. If your kidneys and liver aren’t working well, your doctor may decide to lower your dose of this drug.
  • Addiction. Your doctor will monitor you for signs of addiction while you take this drug.

Your diet

Don’t eat grapefruit or drink grapefruit juice while taking fentanyl. This may lead to dangerously high levels of fentanyl in your body.

Not every pharmacy stocks this drug

Not every dosage form and strength may be available. When filling your prescription, be sure to call ahead.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

SECTION 5 of 5

How Much Does fentanyl Cost?

Sublingual/Translingual spray

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on December 2, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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