Whether you’re starting a new drug or have been taking it for a while, it’s natural to wonder about its possible short- and long-term effects.

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Fentanyl is a narcotic drug that is mainly prescribed for managing severe pain.

Whether you had surgery or you’re championing cancer treatment, a health professional could recommend you take this medication.

As with other opioids, fentanyl may help you manage your symptoms when you take it according to direction. When you don’t, it may lead you to face some health challenges.

Fentanyl is a rapid-acting synthetic opioid that’s 80 to 100 times more powerful than morphine, according to the Drug Enforcement Administration (DEA).

An opioid is a substance, either natural or human-made, that interacts with the opioid receptors in your brain to change your responses to pain.

The DEA also says that about 4 million fentanyl prescriptions are dispensed by doctors in the United States each year.

Some prescription brand names of fentanyl include:

  • Actiq
  • Duragesic
  • Fentora
  • Lazanda
  • Subsys
  • Sublimaze

Fentanyl comes in several forms:

  • transmucosal lozenges
  • sublingual tablets
  • patches
  • nasal sprays
  • injectables

Fentanyl is used to treat severe chronic pain. Off-label, it’s sometimes used for people who are intubated, such as those with renal failure or cancer. It can also be used to treat epilepsy, in combination with other medications.

However, Fentanyl is FDA-approved for anesthesia and some pain conditions only.

“Fentanyl is a powerful synthetic medication which mimics the effects of other opioids in the body and brain, binding to the same receptors in the brain as morphine, codeine, or heroin,” says Hailey Shafir, a licensed clinical addiction specialist in Raleigh, North Carolina.

“These receptors help to relieve pain, but also cause a person to feel a drowsy, relaxed high, similar to drinking a few glasses of wine,” she says.

The DEA explains that, like other opioids, possible side effects of fentanyl include:

  • confusion
  • dizziness
  • drowsiness
  • euphoria
  • nausea
  • pain relief
  • relaxation
  • sedation
  • small pupils
  • slowed breathing
  • urinary retention
  • vomiting

In a medical setting, fentanyl is a highly effective pain reliever that can help your body heal or keep you comfortable.

When not taken according to directions, though, or when taken off-prescription, it can lead to several adverse effects. These include:

  • constipation
  • delirium
  • hallucinations
  • low blood pressure
  • muscle rigidity
  • visual disturbances

If you take Fentanyl for a long time, even when following your doctor’s guidelines, you could develop a physical dependence on it. If you suddenly stop taking the drug, you might experience withdrawal symptoms, too.

Physical dependence doesn’t mean you have developed an addiction, however. This would more likely happen if you’ve taken Fentanyl for a long time, more frequently than needed, and at larger doses than prescribed. It could also happen if you haven’t been prescribed the drug and take it for other reasons.

If mixed with other drugs or alcohol, adverse symptoms can get worse, and on rare occasions, become fatal.

Addiction is no longer a formal diagnosis in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). Instead, we now refer to substance use disorder.

In the case of fentanyl and other opioids, opioid use disorder.

In the simplest terms, opioid use disorder is defined as a condition where you find yourself unable to stop using opioids, even though you want to cut back or quit, and despite negative consequences.

There are 11 criteria in the DSM-5 to diagnose substance use disorder.

The symptoms fall into four main categories. These include:

Impaired control

  • using more of a substance or more often than you intended
  • wanting to cut down or quit, but being unable to
  • spending most of your time using, obtaining, or recovering from taking the drug

Social impairments

  • having trouble with responsibilities and relationships
  • giving up activities you used to care about because of a substance
  • difficulty completing tasks at home, work, or school

Use that may put you or others in jeopardy

  • consuming a substance in risky environments
  • continuing to use a substance despite problems with or from it

Physical dependence

  • developing a tolerance (needing more to get the same effect)
  • having withdrawal symptoms when you haven’t taken a substance
  • craving the drug

Fentanyl is mostly used in clinical settings under medical supervision. That’s why developing an addiction to it is considered rare under these circumstances.

But when it’s not taken according to direction, someone may become dependent on fentanyl. Why? There are many possibilities.

For example, fentanyl does not last long in your system, meaning that you may want to use more within just a few hours.

Also, according to the DEA fentanyl is dealt illegally in the United States and sometimes mixed in with street drugs.

“Folks are not usually seeking fentanyl. It is usually added or mixed in with other substances they may be after, such as heroin or cocaine,” says Jarid Pachter, an associate professor of family and addiction medicine in Southold, New York.

“By the time you have reached the level of addiction where you are buying these products on the street, it is not a high you are chasing. Fentanyl will just prevent you from feeling sick and allow you to function without significant withdrawal symptoms.”

Beyond that, the factors that contribute to use disorder are a bit more difficult to pin down.

“Addiction is somewhat mysterious. We do not know why one person can become physically dependent on a substance and not develop an addiction, and another becomes addicted,” says Jeff Chervenak, an addiction counselor in Avon, Connecticut.

“There are many variables, and genetics may be more than 50 percent of the cause. However, people who do become addicted are overwhelmed by a force that impacts all the things that make you human: physical, mental, emotional, and spiritual,” he says.

If you’re concerned about potential misuse, chances of developing a dependence or having signs of an opioid use disorder, it’s highly advisable you openly talk about it with your health professional.

Substance use disorder looks different for everyone. And not every sign listed here implies addiction on its own. Only a health professional can provide an accurate diagnosis.

Based on the 11 DSM-5 criteria, here’s what it could look like in everyday life when someone’s living with substance use disorder:

Emotional signs

  • aggression
  • anxiety
  • depression
  • disorientation
  • hallucinations
  • impaired judgment
  • paranoia
  • rapid mood changes

Behavioral signs

  • being preoccupied with getting and taking fentanyl
  • being dishonest with loved ones about how much you’re taking
  • buying fentanyl over financial responsibilities
  • having a hard time concentrating at home, work, or school
  • no longer being interested in relationships and hobbies you used to love
  • stealing money or “boosting” (shoplifting) to pay for fentanyl
  • withdrawing from loved ones

Physical signs

  • coordination issues
  • difficulty sleeping
  • extreme cravings
  • fainting
  • headaches
  • irregular periods
  • loss of appetite or weight loss
  • severe constipation
  • skin picking or itching
  • sweating
  • vision issues
  • weight loss

The Centers for Disease Control and Prevention (CDC) says that the majority of opioid overdoses and opioid deaths in the United States are related to fentanyl made illegally, with a large spike in overdoses related to the COVID-19 pandemic.

An important factor is its potency. Just 100 micrograms of fentanyl are equivalent to 10 milligrams of morphine. Just 2 milligrams of fentanyl (the equivalent of a small shake of salt) is enough to cause the death of a full-grown person.

A fentanyl overdose is a medical emergency that requires urgent intervention. Some of the signs of fentanyl overdose include:

  • blue lips or fingernails (cyanosis)
  • clammy skin
  • confusion
  • coma
  • dizziness
  • drowsiness
  • limp body
  • low blood pressure
  • slowed breathing
  • slurred speech
  • vomiting
  • weak pulse

If you see someone who is unresponsive or unconscious, Good Samaritan Laws allow you to help them on the grounds of implied consent.

Consider staying with them until help arrives. It’s a good idea to let the paramedics know any information you have, so they can quickly use naloxone, a lifesaving medication.

When used properly, your doctor will help you taper off fentanyl to reduce the withdrawal symptoms. Most opioid withdrawal symptoms dissipate within a few weeks, but everyone is different.

“Withdrawing from opioids is uncomfortable, causing flu-like symptoms, diarrhea, insomnia, mood swings, and extreme cravings, but it is usually not dangerous,” says Shafir. “Still, because of how uncomfortable the withdrawal is, many people relapse during this phase in order to stop feeling sick.”

By knowing what to expect, you may be in a better position to overcome withdrawal. Some other common withdrawal symptoms from fentanyl include:

  • difficulty sleeping
  • elevated heart rate
  • faster breathing rate
  • joint or muscle pain
  • nausea
  • vomiting

You may find it useful to incorporate several approaches.

Medication-assisted treatment (MAT)

In a SAMHSA-approved clinic, the National Institute of Health (NIH) recommends three medications for medication-assisted treatment:

  • methadone (Dolophine, Methadose)
  • buprenorphine/Naloxone (Suboxone, Subutex)
  • extended-release naltrexone (Vivitrol)

These drugs interact with the same opioid receptors as fentanyl, but to a lesser degree. They take care of the withdrawal symptoms while still allowing you to function and preventing you from feeling “high.”

“These medications also have severe withdrawals when someone stops using them, which is a drawback for people whose ultimate goal is to be completely free from any kind of dependence on a drug,” says Shafir. “These medications should only be taken when prescribed by a licensed medical provider, and when combined with other treatments like therapy, outpatient or inpatient rehab.”

Discussing with a health professional how to appropriately taper these medications is highly advisable. This may help you avoid uncomfortable withdrawal symptoms.

You can take the first step towards recovery with SAMSHA’s treatment finder.

Inpatient treatment

Inpatient treatment provides a safe, secure environment for a two-pronged approach: medication-assisted treatment for the withdrawal symptoms, and individual and group therapy to address the behavioral and psychological dependence on fentanyl.

SAMHSA’s Opioid Treatment Program Directory can help you find options near you.


Talk therapy can help you get to the root of why you feel drawn to use fentanyl and help provide coping strategies to overcome opioid use disorder.

Cognitive-behavioral therapy (CBT) can help you identify distorted thought patterns that may be contributing to your substance use.

Dialectical behavioral therapy (DBT) can help you cope with difficult feelings and practice radical acceptance about your situation.

Support groups

There are many benefits of a support group. These include:

  • connecting with people who’ve had similar experiences
  • having a place to process difficult emotions
  • having people hold you accountable for your actions
  • learning more about substance use and recovery

A group like Narcotics Anonymous may prove helpful on your journey.

Fentanyl is a fast-acting substance and more potent than other opioids, which could sometimes lead to developing dependence, use disorder, and experiencing an overdose.

If you’re experiencing symptoms of fentanyl use disorder, support is available for you. Using multiple approaches may be the most helpful, like medication-assisted treatment, psychotherapy, and support groups.

Recovery is possible.