Fentanyl (injection)

Sold as the brand-name drug Sublimaze, Fentanyl is used to alleviate pain during/after surgery.


Fentanyl is a type of drug known as a narcotic analgesic. In this form, it is given via injection. This injection should only be given by your doctor or a trained nurse, and you should not take this drug home. If you require further pain treatment after surgery, your doctor may prescribe an oral painkiller. This drug acts by affecting the central nervous system, and prevents pain signals from reaching the brain. This can be valuable before, during, or after surgical procedures.

Because of the nature of this drug, it may cause drowsiness or dizziness. Do not drive or walk yourself home after being administered this drug. Call a friend, family member, or taxi to drive you home. This drug may also cause side effects, so make sure you speak to your doctor about what you might experience. If you are allergic to Fentanyl or have an allergy to similar drugs, do not take this medication. If you experience allergy symptoms, contact your doctor immediately or get medical help.

This drug may cause interactions. Keep a detailed list of all your medications, and make sure to present it to your doctor before being given this drug. Your doctor may advise that you stop or pause other treatments until any traces of Fentanyl have been cleared from your system.

You will be given this drug through a sterile needle. The exact dosage changes depending on your condition, age, weight, and tolerance of the drug. If you have questions about the administration, effects, or dosage of this medication, speak to your doctor. Your doctor may give you resources to learn about Fentanyl. Make sure you understand the effects, risks, and side effects. Be sure to mention any questions before your surgery.

Conditions Treated

  • Pain after surgery

Type Of Medication

  • Narcotic analgesic
  • Opioid

Side Effects

Along with reducing pain, this drug may cause additional side effects. Some of these side effects can vary between mild to moderate. If your side effects become severe, be sure to notify someone around you. Serious side effects may be a sign that something is wrong, so do not brush off any troubling experiences. If there is a problem, you may be the only one who can notify a doctor.

Some side effects may not require any medical attention. These can be annoying or unpleasant, but they should dissipate or lessen over time. If you've never had this drug before, you may be more likely to experience side effects. Mild side effects include:

  • Nausea and/or vomiting
  • Lightheadedness and/or dizziness
  • Constipation
  • Mild headache
  • Slowed heartbeat and breathing
  • Sweating

If these side effects persist or worsen, let someone know. The doctor may stop/lower your dose of Fentanyl. The side effects disappear after lowering or stopping the administration. Let your doctor know if the side effects persist afterwards, especially if you return home after the treatment.

Some side effects can become serious. Notify someone immediately if you experience:

  • Changes in mental condition (confusion, agitation, or possible hallucinations)
  • Unusual tiredness/fatigue
  • Chest pain
  • Irregular/shortened/shallow breathing
  • Severe muscle stiffness
  • Shortness of breath
  • Fainting
  • Pale/blue lips and skin

If you have already gone home and you feel life is in danger, contact medical help right away. While Fentanyl has a high rate of success, it is not right for everyone. Let a doctor or nurse know if you experience anything strange, painful, or troubling during your Fentanyl treatment.

Some side effects can be immediately life threatening. Contact a doctor or paramedic right away if any of the following occur:

  • Seizure
  • Severe drowsiness, where the patient cannot be woken up
  • Repeated fainting
  • Difficulty breathing

Get help right right away if any of these side effects occur, and stay with the affected person until help arrives. If you are the one suffering from these symptoms, try to stay conscious and calm until help arrives.


Because this drug is given to you by a nurse/doctor, you do not need to personally determine the dose. The doctor will calculate the necessary dosage beforehand, based on your personal information and health records. They may ask you questions to help decide on a safe, reliable dose of Fentanyl. Dosage can change depending on your weight, condition, and resistance to the drug. If you've taken Fentanyl before, be sure to mention your reaction to your doctor.

This drug will be given with a needle, and the nurse will administer it as a shot into the muscle. While it may feel unpleasant at first, you will not feel pain after the drug kicks in. Children receiving this drug should be monitored closely, and the doctor may administer it over the course of a few doses to avoid shocking their system. Unless you are told otherwise, you will likely be able to stay with your child during the injection.


Some drugs may interact with Fentanyl and cause unwanted side effects, decreased efficacy, or complications. Make sure to keep track of all your medications, including over the counter drugs and herbal remedies. Mention all of these to your doctor, and do not begin any new prescriptions until your Fentanyl treatment is over.

Your doctor might ask you to stop current treatments an prescriptions until your surgery is finished. This is for your safety, and you should only take drugs that your doctor approves of during this time. Some drugs have mild interactions, and your doctor may settle for lowering your doses of those medications. Follow their instructions carefully, and contact them if you have questions.

Common interactions with Fentanyl include:

  • Other opioids, including prescription cough medicine and painkillers.
  • MAO inhibitors should not be taken with Fentanyl under any circumstances. You should stop taking them two weeks before surgery to be safe.
  • Any drugs containing serotonin. Taking antidepressants with Fentanyl can result in serotonin syndrome, a toxicity of serotonin in the brain.
  • Sleep medications
  • Anxiety medications
  • Antihistamines
  • Seizure medications
  • Sedatives or tranquilizers
  • Certain antibiotics and antifungals
  • HIV drugs
  • Calcium channel blockers
  • Alcohol
  • Marijuana

This list is not exhaustive, so do not use it as your primary source of information when identifying interactions. You should keep all of your medications on record, and mention any new or unlisted drugs to your doctor. Narcotics like Fentanyl can have a large number of potential interactions, so you should stay vigilant while taking them.

If you are currently taking a drug in the above list, talk to your doctor. You may need to stop/lower the dose of your medication. After the Fentanyl has been cleared from your system, you should be able to begin your treatment again.

Interactions can vary in intensity. Some may result in mild, unpleasant side effects, while others can be dangerous or even fatal. Avoid any interactions if you can, and limit the interactions that do occur. Speak to your doctor for more information, and talk to friends or family that have taken Fentanyl before.


Like many drugs in this category, Fentanyl may pose risks to your health. While many people can take this drug without issue, some may experience adverse effects. If you have concerns about taking this drug, speak to your doctor to decide if Fentanyl is right for you.

Fentanyl may affect some people more than others. Before being administered this drug, your doctor will weigh the good it will do versus the possible risk. If they clear you for treatment with Fentanyl, you are likely safe to take it.

If you develop a fever while taking this drug, tell your doctor immediately. A rising internal temperature can lead to a higher risk of overdose. Likewise, your doctor will not administer this drug if you have an existing fever. This drug also causes drowsiness, so do not operate machinery or drive after being administered this drug. Ask someone else to take you home, like a family member or taxi driver.

If you have an allergy to this drug or drugs of this kind (opioids/narcotics), be sure to notify someone before administration. If you experience allergy symptoms after being given Fentanyl, alert nurses or doctors immediately. Allergy symptoms include:

  • Itching
  • Closing of the airways
  • Lightheadedness
  • Unexplained, persistent cough
  • Hives
  • Swelling of the face/tongue/hands
  • Tightness in the chest
  • Trouble breathing
  • Unexplained fever

You may not be able to take Fentanyl if you have a history of breathing problems, slow heartbeat, liver/kidney disease, or a brain tumor. If you have any conditions that may involve your heart, lungs, or other vital organs, tell your doctor. They may switch you to another painkiller or lower your dose accordingly.

Pregnant women should only use this drug as needed. Fentanyl can cause harm to the unborn child if it is given in high doses, so be sure to alert your doctor if you are pregnant. You may require special care, a lowered dose, or an alternate form of pain relief.

You should only receive Fentanyl injections under the supervision of a doctor or nurse. Oral/patch forms of this drug have different warnings and dosage requirements. This drug has a risk of addiction, so use it sparingly in all forms.


This drug will be handled and prepared by trained medical professionals, so there is no need for you to store it. If you have a take-home prescription for this drug, you likely have an oral/patch form of the medication, not the injection. This form of Fentanyl has different storage and dosage requirements, so make sure you are reading the proper page.

The internet can be a valuable source of information, but you should direct your questions towards a doctor if you can. If you have concerns about this drug or how it's handled, feel free to ask a nurse or doctor before you're given the shot.


Fentanyl injections are used as surgical painkillers, and they can reduce and eliminate pain both during and after surgery. This treatment can be valuable for anyone receiving painful surgery, and it can make recovery for these patients easier and less painful. Due to Fentanyl's high rate of addiction, this drug should only be used and prescribed by doctors.

If your doctor has approved you for treatment with Fentanyl, you are likely safe to use it. However, if you have a condition that makes this drug dangerous, be sure to let your doctor know. Allergies, existing diseases, and other conditions can affect the safety of this medication. Be sure to read and understand all the given information about Fentanyl before taking it.

This drug will only be given to you in a hospital/care center. You should not have to take this drug home, prepare it, or administer it yourself. A trained nurse or doctor will do that for you. If you feel that you need further pain treatment, be sure to let your doctor know before you go home. They may prescribe a similar drug, or the oral form of Fentanyl. These drugs may have different terms of use, so be sure to review them as well.

This drug should not be used with antidepressants, MAO inhibitors, or other opioids. This drug may also interact with other medications, so be sure to stop/lower the doses of all interactive medications before taking this drug. Check with your doctor to see if any of your current prescriptions interact with Fentanyl.

Notify your doctor if you experience any unusual, persistent, or troubling side effects. Side effects can vary between mild and severe, so monitor yourself or your children after this drug's administration. If you think you may need this drug, or have had it recommended to you, be sure to speak to your doctor before any treatment.