Fentanyl Injection

Fentanyl may be habit forming and should be used exactly as directed. Tell your doctor if you or anyone in your family drinks or has ever drunk large amounts of alcohol, uses or has ever used street drugs, or has overused prescription medications, or has had an overdose, or if you have or have ever had depression or another mental illness.

Fentanyl may cause serious or life-threatening breathing problems, especially when starting your treatment and any time your dose is increased. Your doctor will monitor you carefully during your treatment. Tell your doctor if you have or have ever had lung disease such as chronic obstructive pulmonary disease (COPD; a group of diseases that affect the lungs and airways), central sleep apnea (brain doesn't send proper signals to the muscles that control breathing), head injury a brain tumor, or any condition that increases the amount of pressure in your brain. The risk that you will develop breathing problems may be higher if you are an older adult or are weak or malnourished due to disease. If you experience any of the following symptoms after treatment, call your doctor immediately or get emergency medical treatment: slowed breathing, long pauses between breaths, or shortness of breath.

Taking certain medications with fentanyl may increase the risk that you will develop serious or life-threatening breathing problems, sedation, or coma. Tell your doctor what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the dosages of your medications and will monitor you carefully. If you receive fentanyl with other medications and you develop any of the following symptoms, call your doctor immediately or seek emergency medical care: unusual dizziness, lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness. Be sure that your caregiver or family members know which symptoms may be serious so they can call the doctor or emergency medical care if you are unable to seek treatment on your own.

Uses
How to Use
Precautions
Side Effects
More Information

Why is this medicine prescribed?

Fentanyl is used before and during surgery or other procedures to relieve pain and cause a loss of feeling or awareness. Fentanyl is in a class of medications called narcotic (opiate) analgesics. It works by changing the way the brain and nervous system respond to pain.

Are there other uses for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

How should this medicine be used?

Fentanyl injection comes as a solution (liquid) to be injected into a vein or muscle by a doctor or other trained healthcare provider. It is usually given as frequently and in amounts required to maintain anesthesia or sedation depending on age, health, and other factors. Your dose will be adjusted based on your response. You will be monitored carefully by your healthcare provider while you are receiving fentanyl and for a period of time afterwards.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

What special precautions should I follow?

Before receiving fentanyl,

tell your doctor and pharmacist if you are allergic to fentanyl, any opiate drugs, any other medications, or any of the ingredients in fentanyl solution. Ask your pharmacist for a list of the ingredients.
tell your doctor if you have or have ever had seizures; low blood pressure; adrenal insufficiency (condition in which the adrenal glands do not produce enough of certain hormones needed for important body functions); or pancreas, gallbladder, heart, liver, or kidney disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding.
you should know that this medication may decrease fertility in men and women when used for a longer period of time. Talk to your doctor about the risks of using fentanyl.
you should know that fentanyl may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
you should know that fentanyl may cause constipation. Talk to your doctor about using other medications to prevent or treat constipation while you receive fentanyl.
ask your doctor about the safe use of alcoholic beverages after you receive fentanyl. Alcohol can make certain side effects from fentanyl worse.

What special dietary instructions should I follow?

Be sure to follow any dietary instructions that your doctor gives to you after your surgery.

What side effects can this medicine cause?

Fentanyl may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:

nausea
vomiting
dizziness
blurred vision
difficulty urinating

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately or get emergency medical treatment:

agitation, hallucinations (seeing things or hearing voices that do not exist), fever, sweating, confusion, fast heartbeat, shivering, severe muscle stiffness or twitching, loss of coordination, or diarrhea
hives; rash; itching; swelling of the eyes, face, mouth, lips or throat; hoarseness; difficulty breathing or swallowing
worsening pain, increased sensitivity to pain, or new pain
seizures

Fentanyl may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( https://www.fda.gov/Safety/MedWatch ) or by phone (

1-800-332-1088).

What other information should I know?

Keep all appointments with your doctor.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

¶ This branded product is no longer on the market. Generic alternatives may be available.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS ^® Patient Medication Information™. © Copyright, 2025. The American Society of Health-System Pharmacists ^® , 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: February 15, 2025.