Medically reviewed by Drugs.com. Last updated on Dec 9, 2021.
Fentanyl citrate injection is a Schedule II controlled substance with abuse liability similar to other opioid analgesics. Assess risk prior to initiation and monitor for signs of misuse, abuse, and addiction during treatment. Serious, life-threatening, or fatal respiratory depression may occur. Monitor for respiratory depression, especially during initiation or following a dose increase. Use with CYP3A4 inhibitors or inducers may change fentanyl plasma levels resulting in a fatal overdose and monitoring is recommended. Concomitant use of opioids with benzodiazepines or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients with inadequate alternative treatment options, limit dosage and duration to the minimum required, and monitor for respiratory depression and sedation .
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Analgesic
Chemical Class: Opioid
Uses for fentanyl
Fentanyl injection is used to relieve severe pain during and after surgery. It is also used with other medicines just before or during an operation to help the anesthetic (numbing medicine) work better.
Fentanyl belongs to the group of medicines called narcotic analgesics (pain medicines). It acts in the central nervous system (CNS) or brain to relieve pain. Some of its side effects are also caused by actions in the CNS such as drowsiness or dizziness.
Fentanyl is to be given only by or under the immediate supervision of your doctor.
Before using fentanyl
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For fentanyl, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to fentanyl or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of fentanyl injection in children younger than 2 years of age. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of fentanyl injection in the elderly. However, elderly patients are more likely to have age-related lung, kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving fentanyl injection.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving fentanyl, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using fentanyl with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using fentanyl with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Calcium Oxybate
- Chloral Hydrate
- Eslicarbazepine Acetate
- Gabapentin Enacarbil
- Magnesium Oxybate
- Methylene Blue
- Morphine Sulfate Liposome
- Nitrous Oxide
- Opium Alkaloids
- Potassium Oxybate
- Ropeginterferon Alfa-2b-njft
- Sodium Oxybate
- St John's Wort
- Tolonium Chloride
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using fentanyl with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use fentanyl, or give you special instructions about the use of food, alcohol, or tobacco.
- Grapefruit Juice
Other medical problems
The presence of other medical problems may affect the use of fentanyl. Make sure you tell your doctor if you have any other medical problems, especially:
- Adrenal problems or
- Brain tumor, history of or
- Breathing or lung problems (eg, COPD, respiratory depression, sleep apnea) or
- Cor pulmonale (serious heart condition) or
- Drug dependence, especially with narcotics, or history of or
- Head injury, history of or
- Heart disease or
- Hypokalemia (low potassium levels in the blood) or
- Hypomagnesemia (low magnesium levels in the blood)—Use with caution. May increase risk for more serious side effects.
- Bradycardia (slow heart rhythm) or
- Gallbladder problems or
- Heart rhythm problems (eg, QT prolongation) or
- Hypertension (high blood pressure) or
- Hypotension (low blood pressure) or
- Pancreatitis (inflammation or swelling of the pancreas) or
- Seizures, history of—Use with caution. May make these conditions worse.
- Kidney disease or
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper use of fentanyl
A doctor or other trained health professional will give you or your child fentanyl in a hospital. Fentanyl is given as a shot into a muscle or vein.
Precautions while using fentanyl
It is very important that your doctor check you closely while you or your child are receiving fentanyl. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it.
Fentanyl may cause a serious allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you or your child have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using fentanyl.
Do not use too much of fentanyl or use it more often than your doctor tells you to. This can be life-threatening. Symptoms of an overdose include: extreme dizziness or weakness, slow heartbeat or breathing, seizures, trouble breathing, and cold, clammy skin. Call your doctor right away if you notice these symptoms.
Dizziness, lightheadedness, or fainting may occur with fentanyl, especially when you get up suddenly from a lying or sitting position. Getting up slowly may help lessen this problem. Also, lying down for a while may relieve the dizziness or lightheadedness.
Fentanyl will add to the effects of alcohol and other central nervous system (CNS) depressants. CNS depressants are medicines that slow down the nervous system, which may cause drowsiness or make you less alert. Some examples of CNS depressants are antihistamines or medicine for hay fever, allergies, or colds, sedatives, tranquilizers, or sleeping pills, prescription pain medicine or narcotics, barbiturates or seizure medicines, muscle relaxants, or anesthetics (numbing medicines), including some dental anesthetics. This effect may last for a few days after you stop using fentanyl. Check with your medical doctor or dentist before taking any of the above while you or your child are receiving fentanyl.
Fentanyl may cause sleep-related breathing problems (eg, sleep apnea, sleep-related hypoxemia). Your doctor may decrease your dose if you have sleep apnea (stop breathing for short periods during sleep) while using fentanyl.
Fentanyl may make you dizzy, drowsy, confused, or disoriented. Make sure you know how you react to fentanyl before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
Fentanyl may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.
Using narcotics for a long time can cause severe constipation. To prevent this, your doctor may direct you to take laxatives, drink a lot of fluids, or increase the amount of fiber in your diet. Be sure to follow the directions carefully, because continuing constipation can lead to more serious problems.
If you have been using fentanyl regularly for several weeks or longer, do not change your dose or suddenly stop using it without checking with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping it completely. This may help prevent worsening of your condition and reduce the possibility of withdrawal symptoms, such as abdominal or stomach cramps, anxiety, fever, nausea, runny nose, sweating, tremors, or trouble sleeping.
Fentanyl may increase risk for muscle rigidity and movement. Tell your doctor if you or your child have stiff or rigid muscles after using fentanyl.
Check with your doctor right away if you have anxiety, restlessness, a fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, or see or hear things that are not there. These may be symptoms of a serious condition called serotonin syndrome. Your risk may be higher if you also take certain other medicines that affect serotonin levels in your body.
Using fentanyl while you are pregnant may cause neonatal withdrawal syndrome in your newborn babies. Tell your doctor right away if your baby has an abnormal sleep pattern, diarrhea, a high-pitched cry, irritability, shakiness or tremors, weight loss, vomiting, or fails to gain weight.
Using too much of fentanyl may cause reduced infertility (unable to have children). Talk with your doctor before using fentanyl if you plan to have children.
Do not eat grapefruit or drink grapefruit juice while you are using fentanyl.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Fentanyl side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
- Chest pain or discomfort
- difficult or troubled breathing
- irregular, fast or slow, or shallow breathing
- lightheadedness, dizziness, or fainting
- pale or blue lips, fingernails, or skin
- severe muscle stiffness
- slow or irregular heartbeat
- unusual tiredness
Incidence not known
- Blurred vision
- change in consciousness
- difficulty with swallowing
- fast heartbeat
- feeling cold
- hives, itching, or skin rash
- inability to move the eyes
- inability to sit still
- increased blinking or spasms of the eyelid
- pounding in the ears
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- seeing, hearing, or feeling things that are not there
- sticking out the tongue when not meaning to
- tightness in the chest
- uncontrolled twisting movements of the neck, trunk, arms, or legs
- unusual facial expressions
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
- Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
- increased sweating
- redness of the skin
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
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- Drug class: narcotic analgesics
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