Medically Reviewed

Fentanyl Addiction: Side Effects, Symptoms, and Rehab Treatment

4 min read · 7 sections
Fentanyl is an opioid, like morphine, but 50 to 100 times more potent.1 It is often prescribed for severe pain.1 However, it is also manufactured and sold illegally. Fentanyl is a controlled substance in schedule II under the Controlled Substances Act, meaning it has a high potential for misuse, which can lead to severe psychological or physical dependence.2
What you will learn:
The statistics surrounding fentanyl use
What fentanyl is
Signs of fentanyl addiction
Withdrawal symptoms
Side effects of fentanyl use
What to expect in fentanyl addiction treatment

In 2021, there were 70,601 fatal overdoses involving synthetic opioids other than methadone (primarily from fentanyl and fentanyl analogues).3

Statistics on Fentanyl Use and Misuse

Fentanyl use is dangerous, as it can lead to addiction or a life-threatening overdose. The following are statistics on fentanyl use and misuse:1,4-6

  • More than 150 people die each day from overdoses related to synthetic opioids, like fentanyl.
  • Approximately 991,000 people aged 12 or older misused prescription fentanyl products in 2022. This number does not include the individuals who misused illicitly manufactured fentanyl or those who mixed it with other substances such as heroin.
  • In 2021, there were nearly 123,000 fentanyl-related emergency department visits in the U.S.
  • Since 2018, the number of fentanyl trafficking offenses increased by 460.7%.

What Is Fentanyl?

Fentanyl is a synthetic opioid originally derived from the opioid poppy (Papaver somniferum).7 Doctors prescribe it to treat people suffering from intense pain after surgery. Additionally, physicians may also prescribe fentanyl for cancer patients with chronic pain who have developed a tolerance—meaning it takes more of a drug to produce the same effects—to less powerful opioids or who experience breakthrough or other transient exacerbations of pain.8

Fentanyl works by binding to the body’s opioid receptors in areas of the brain that control pain and emotions.8 These are the same receptors that bind endorphins, the body’s natural painkiller. There are many types of endorphins, and beta-endorphins are released during or after the body’s physiological response to a stressor or pain. Endorphins are also released as a result of pleasurable things like laughter, sex, and exercise.9 When opioids bind to those receptors, the body experiences similar feelings of both pain relief and pleasure in its reward circuit.10

However, administration of opioid drugs inhibit the production of endorphins and in addition to increased analgesia can also overload the brain with reward circuit signals, resulting in feelings of euphoria.10,11 With repeated use, the brain adapts to the presence of opioids, which can make it difficult to feel pleasure without opioids like fentanyl and can lead to an inability to feel pleasure from things one previously enjoyed, which may indicate someone has an opioid use disorder, the clinical term for an addiction to fentanyl or other opioids.8,10

Individuals who take prescription fentanyl get it as a shot, lozenge, or patch.8 The illegally produced fentanyl, on the other hand, comes as a powder or liquid.1,8 Because it has no taste or smell and is cheap to illicitly manufacture, it is commonly mixed into other drugs, such as heroin, cocaine, and methamphetamine, often unknowingly by those purchasing them.1 It is also made into pills to look like other prescription opioids and medications, such as Xanax or Adderall.8 Additionally, as a liquid, fentanyl gets put in eye drops, nasal sprays, and candy.1,8

Side Effects of Fentanyl Use

As with any drug, fentanyl can cause adverse side effects, including:9

  • Constipation.
  • Confusion.
  • Drowsiness.
  • Slowed breathing.
  • Nausea.
  • Sedation.
  • Unconsciousness.

Additionally, anybody using fentanyl or taking opioid medications is at increased risk of overdose.

Signs of Fentanyl Overdose

Overdose occurs when fentanyl produces serious, potentially life-threatening effects. When individuals overdose on fentanyl, their breathing can dangerously slow or stop, thus decreasing the amount of oxygen getting to the brain and producing a condition called hypoxia. Hypoxia can lead to coma, brain damage, or even death.10 Opioid overdose is considered a medical emergency but can be reversed with the administration of naloxone.11

Illicitly manufactured fentanyl is a primary driver of opioid overdose deaths.12 Additionally, other illicit drugs and counterfeit pills are increasingly adulterated with fentanyl. In fact, by 2021, stimulants were the most common drug class found in fentanyl-involved overdoses in every state in the U.S. While some of this polysubstance use happens unknowingly with the individual being unaware of the presence of fentanyl, recent research suggests that polysubstance use, especially the combination of stimulants like cocaine and methamphetamine with fentanyl, is becoming sought-after and more commonplace.13

The signs of an overdose involving opioids such as fentanyl include:1,11

  • Small, constricted, “pinpoint pupils”
  • Loss of consciousness.
  • Choking or gurgling signs.
  • Vomiting.
  • Limp body.
  • Cold and/or clammy skin.
  • Blue or purple fingernails, lips, or skin.

If you suspect that you or someone else might be experiencing a fentanyl overdose, call 911 immediately, administer naloxone (Narcan) if available, try to keep the individual awake and breathing, lay them on their side, and don’t leave until emergency assistance arrives.1,11

Symptoms of Fentanyl Addiction

Recognizing the symptoms of an opioid addiction is imperative to getting treatment. Addiction is a treatable, chronic medical condition involving complex interactions between brain circuits, genetics, environment, and life experiences. Individuals with addiction engage in uncontrollable substance use and continue despite the harmful consequences.14

More specifically, you may have a fentanyl addiction if you experience 2 or more of a set of symptoms outlined in the Diagnostic and Statistical Manual for Mental Disorders, 5th edition, which is used by clinicians who are trained to diagnose individuals with opioid use disorders and other substance use disorders. The symptoms of an opioid use disorder include:15

  • Using more opioids than you intended.
  • Using opioids for longer than you intended.
  • Spending a great amount of time obtaining, using, or recovering from the effects of fentanyl or other opioids.
  • Having cravings to use fentanyl or other opioids.
  • An inability to complete duties at work, school, or home due to opioid use.
  • Continuing to use fentanyl or other opioids even if it negatively impacts your relationships.
  • Giving up things you previously enjoyed due to opioid use.
  • Frequently using fentanyl or other opioids in physically dangerous situations.
  • Continuing to use opioids despite physical or mental problems you know are caused by it.
  • Developing tolerance to opioids.
  • Experiencing withdrawal symptoms when stopping the use of fentanyl or other opioids.

Even if you use fentanyl as prescribed, it is possible to develop tolerance and experience withdrawal symptoms (i.e., dependence).16 In cases where a person is prescribed fentanyl or other opioids, the last two criteria don’t count toward a diagnosis of opioid use disorder.

Tolerance and dependence are natural consequences of taking opioids long term. Tolerance to fentanyl is a need to use more of the drug to achieve the desired effect, whether that is intoxication or pain relief. As you continue to use the same amount of the drug, there is a diminished sensitivity to its effects.16

The science behind fentanyl addiction.

Fentanyl Withdrawal Symptoms

Individuals who have developed a dependence to fentanyl experience withdrawal symptoms when they stop taking it. These symptoms may include:8

  • Nausea or vomiting.
  • Achy muscles and bones.
  • Cold flashes.
  • Goosebumps.
  • Uncontrollable leg movements.
  • Diarrhea.
  • Insomnia.
  • Severe cravings.

An opioid use disorder occurs as opioid use starts to take over a person’s life, resulting in continued drug use despite negative consequences. There is no way to predict exactly who will develop an addiction. However, addiction becomes more likely for people who use higher doses, for longer periods, start at a young age, or who have a parent with a substance use disorder.10

What to Expect in Fentanyl Addiction Treatment

If you or a loved one struggle with fentanyl use or the misuse of opioids, there are treatment options. There is no one-size-fits-all for the treatment of fentanyl misuse. Effective treatment is tailored to each person’s individual needs but may include:17

Detox. Medically managed detoxification is often the first step in a comprehensive treatment plan. Detox allows your body to safely rid itself of the fentanyl while you experience the physical and emotional withdrawal symptoms as comfortably as possible under the guidance of a medical professional.

Inpatient rehab. Inpatient addiction treatment refers to 24/7 care. It requires you to move into a hospital or residential treatment center for the duration of treatment, which may include individual and group counseling, education, behavioral therapies, and medication if needed. Living in the treatment facility helps remove the stress of home or work and allows you to focus on recovery in a supportive environment.

Outpatient rehab. Outpatient rehab programs require you to attend onsite (or virtual) counseling sessions and therapies, which look similar or identical to inpatient services, but return home or to a sober living environment after treatment.

Aftercare. Aftercare is also called continuing care, and it sets you up for lasting recovery with community support and accountability after completing a formal treatment program and may include mutual-help groups and/or sober living environments.

The Cost of Fentanyl Addiction Treatment

Most rehab facilities accept a variety of insurance plans and self-pay options; other centers offer sliding-scale payment plans based on your income or low-cost and free treatment for individuals who cannot pay.

In general, the cost of fentanyl addiction treatment is based on a few factors, including:

  • The type of care provided.
  • The duration of treatment.
  • The type of insurance coverage you have.
  • The facility’s location.
  • Amenities offered, such as private rooms and recreational activities, for instance.

Typically, inpatient care, which provides 24/7 treatment, costs more than an outpatient program. Similarly, luxury amenities cost more than standard treatment programs.

How Long Does Rehab for Fentanyl Addiction Last?

The length of treatment for fentanyl addiction depends on the severity of your addiction, your specific treatment needs, and your continued engagement with treatment.16

Substance use disorders are chronic diseases, and recovery is a lifetime commitment. Therefore, remaining in fentanyl addiction treatment for the entire duration and setting up a lifestyle and support system after treatment that aids you in maintaining your goals can help you live a healthy, substance-free life long term.

American Addiction Centers (AAC) operates substance use treatment facilities throughout the country. If you or someone you love struggle with fentanyl addiction, call AAC at . Speak to one of our compassionate and knowledgeable admissions navigators, who can listen to your story, answer your questions, explain your options, and help you begin your recovery journey.

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