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Fentanyl Injection

Fentanyl is an opioid medication to treat severe pain. It works by blocking pain signals in your brain. A healthcare provider will give you an injection of Fentanyl in a hospital or clinic. Providers may use this medication when other pain medications don’t work well enough or can’t be tolerated. It may cause drowsiness and other side effects.

What is this medication?

FENTANYL (FEN ta nil) treats severe pain. It may also be used to cause drowsiness before a procedure. It is often prescribed when other pain medications do not work well enough or cannot be tolerated. It works by blocking pain signals in the brain. It belongs to a group of medications called opioids.

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This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

COMMON BRAND NAME(S): Sublimaze

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions:

  • Brain tumor
  • Frequently drink alcohol
  • Gallbladder disease
  • Head injury
  • Heart disease
  • Kidney disease
  • Liver disease
  • Low blood pressure
  • Lung or breathing disease, such as asthma
  • Mental health conditions
  • Problems urinating
  • Seizures
  • Stomach or intestine problems
  • Substance use disorder
  • An allergic or unusual reaction to fentanyl, other medications, foods, dyes, or preservatives
  • Pregnant or trying to get pregnant
  • Breastfeeding

How should I use this medication?

This medication is injected into a vein or muscle. It is given in a hospital or clinic.

Talk to your care team about the use of this medication in children. Special care may be needed.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

This does not apply. This medication is not for regular use.

What may interact with this medication?

Do not take this medication with any of the following:

  • Mifepristone

This medication may also interact with the following:

  • Alcohol
  • Antihistamines for allergy, cough, and cold
  • Antiviral medications for HIV or AIDS
  • Atropine
  • Certain antibiotics, such as clarithromycin, erythromycin, rifampin
  • Certain medications for anxiety or sleep
  • Certain medications for bladder problems, such as oxybutynin, tolterodine
  • Certain medications for blood pressure, heart disease, irregular heartbeat
  • Certain medications for depression, such as amitriptyline, fluoxetine, sertraline
  • Certain medications for diabetes, such as pioglitazone, troglitazone
  • Certain medications for fungal infections, such as ketoconazole, itraconazole
  • Certain medications for migraine headache, such as almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan, zolmitriptan
  • Certain medications for nausea or vomiting, such as aprepitant, dolasetron, granisetron, ondansetron
  • Certain medications for seizures, such as phenobarbital, phenytoin, primidone
  • Certain medications for stomach problems, such as dicyclomine, hyoscyamine
  • Certain medications for travel sickness, such as scopolamine
  • Certain medications for Parkinson disease, such as benztropine, trihexyphenidyl
  • Cimetidine
  • Diuretics
  • General anesthetics, such as halothane, isoflurane, methoxyflurane, propofol
  • Grapefruit juice
  • Ipratropium
  • Linezolid
  • Local anesthetics, such as lidocaine, pramoxine, tetracaine
  • MAOIs, such as Carbex, Eldepryl, Marplan, Nardil, and Parnate
  • Medications that relax muscles for surgery
  • Methylene blue
  • Other opioid medications for pain or cough
  • Phenothiazines, such as chlorpromazine, mesoridazine, prochlorperazine, thioridazine
  • St. John's wort
  • Steroid medications, such as prednisone or cortisone

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This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Tell your care team if your pain does not go away, if it gets worse, or if you have new or a different type of pain. You may develop tolerance to this medication. Tolerance means that you will need a higher dose of the medication for pain relief. Tolerance is normal and is expected if you take this medication for a long time.

Taking this medication with other substances that cause drowsiness, such as alcohol, benzodiazepines, or other opioids can cause serious side effects. Give your care team a list of all medications you use. They will tell you how much medication to take. Do not take more medication than directed. Call emergency services if you have problems breathing or staying awake.

Children may be at higher risk for side effects. Stop giving this medication and call emergency services right away if your child has slow or noisy breathing, has confusion, is unusually sleepy, or not able to wake up.

Long term use of this medication may cause your brain and body to depend on it. This can happen even when used as directed by your care team. You and your care team will work together to determine how long you will need to take this medication. If your care team wants you to stop this medication, the dose will be slowly lowered over time to reduce the risk of side effects.

Naloxone is an emergency medication used for an opioid overdose. An overdose can happen if you take too much of an opioid. It can also happen if an opioid is taken with some other medications or substances such as alcohol. Know the symptoms of an overdose, such as trouble breathing, unusually tired or sleepy, or not being able to respond or wake up. Make sure to tell caregivers and close contacts where your naloxone is stored. Make sure they know how to use it. After naloxone is given, the person giving it must call emergency services. Naloxone is a temporary treatment. Repeat doses may be needed.

This medication may affect your coordination, reaction time, or judgment. Do not drive or operate machinery until you know how this medication affects you. Sit up or stand slowly to reduce the risk of dizzy or fainting spells. Drinking alcohol with this medication can increase the risk of these side effects.

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This medication will cause constipation. If you do not have a bowel movement for 3 days, call your care team.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy and drinking plenty of water may help. Contact your care team if the problem does not go away or is severe.

Talk to your care team if you may be pregnant. Prolonged use of this medication during pregnancy can cause temporary withdrawal in a newborn.

Talk to your care team before breastfeeding. Changes to your treatment plan may be needed. If you breastfeed while taking this medication, seek medical care right away if you notice the child has slow or noisy breathing, is unusually sleepy or not able to wake up, or is limp.

Long-term use of this medication may cause infertility. Talk to your care team if you are concerned about your fertility.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible:

  • Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
  • CNS depression—slow or shallow breathing, shortness of breath, feeling faint, dizziness, confusion, trouble staying awake
  • Low adrenal gland function—nausea, vomiting, loss of appetite, unusual weakness or fatigue, dizziness
  • Low blood pressure—dizziness, feeling faint or lightheaded, blurry vision
  • Muscle stiffness

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Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):

  • Dizziness
  • Drowsiness
  • Nausea
  • Vomiting

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medication?

This medication is given in a hospital or clinic. It will not be stored at home.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

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Note: Introduction and Additional Common Questions written and medically approved by Cleveland Clinic professionals.

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