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Short- and Long-Term Side Effects of Fentanyl

Fentanyl is a potent synthetic opioid that is 50 times stronger than heroin and 100 times more powerful than morphine.1 While it may be prescribed for people suffering from severe pain, such as after surgery, it is also frequently misused.2 Prescription fentanyl is known by brand names like Actiq, Duragesic, or Sublimaze.3

Individuals who use or misuse fentanyl may wonder, what does fentanyl do to your body, and should be aware of fentanyl side effects. One of the most significant effects is overdose, which can happen even on the first use due to its high potency. Additionally, people may be using fentanyl unknowingly if they use other substances that are cut with fentanyl, such as heroin, cocaine, methamphetamine, and MDMA, which can increase overdose risk.1,3 Drug dealers use fentanyl as an additive because it’s cheap and potent, so it only takes a little to create a high.1

Side effects of fentanyl use and misuse can also include addiction, the dangers of polysubstance use (if other substances are knowingly or unknowingly used at the same time), and specific short-term fentanyl effects and long-term effects of fentanyl. If you or someone you know uses fentanyl, you should know that misuse can be successfully managed with treatments such as medication, counseling, and behavioral therapies.3

This article will help you understand the various effects of fentanyl misuse and addiction, including overdose, and explain how to find help so you, or your loved one, can begin the path to recovery.

Short-Term Effects of Fentanyl

What are the side effects of fentanyl, and why do they occur? As with other opioids, fentanyl works by activating opioid receptors, which are found in the brain and throughout the body.3 This results in reduced pain sensitivity and various short-term effects of fentanyl, that include the following:

  • Feelings of happiness or euphoria.3,4
  • Drowsiness.3
  • Nausea.3
  • Vomiting.5
  • Dry mouth.5
  • Itching.5
  • Sweating.5
  • Confusion.3
  • Constipation.3

If fentanyl is misused, more serious short term side effects can occur which include the following:

  • Hypotension (low blood pressure).4
  • Hallucinations.4
  • Delirium.4
  • Breathing difficulties.3
  • Loss of consciousness.3
  • Overdose, which can happen after just one use and even with very small doses.1 Overdose, including fatal overdose, can be classified as both a short-term and long-term effect since it can happen at any time.5

Additionally, polysubstance use, or combining fentanyl with other drugs or medications (whether you take them knowingly or unknowingly), can be risky and dangerous because it can intensify side effects of each substance, lead to unpredictable effects, and increase the risk of overdose.6

Long-Term Effects of Fentanyl

Over time, long-term fentanyl use can lead to a variety of effects and impact your entire life. Some of the more common fentanyl long-term side effects include:

  • Tolerance, meaning you need to take more frequent or higher doses of fentanyl over time in order to experience previous effects.5
  • Dependence, which occurs when your body has adapted to the presence of fentanyl and you need to take it to feel normal; you may experience withdrawal symptoms when you stop using it.5
  • Addiction, otherwise known as opioid use disorder. This involves continued and compulsive fentanyl use despite the negative life consequences and health problems it causes.3
  • Harm to interpersonal relationships, including family, friends, and relationships with work colleagues.7
  • Problems finding or maintaining employment due to ongoing fentanyl use.7
  • Financial difficulties due to spending money on drugs; people may steal money, personal belongings, or medication from others in order to obtain the drug.7
  • Transitioning to heroin use, which is reported to occur in up to 75% of people who started out taking prescription opioids.7
  • Increased risk of contracting infectious diseases, such as HIV and hepatitis, due to injecting fentanyl.7
  • Overdose, which, as mentioned above, can be both a potential short-term and long-term effect of fentanyl and lead to premature death.1
  • Permanent brain damage due to hypoxia, which can occur due to overdose and can lead to reduced oxygen in the brain, as well as damage to other organs, especially if you use other substances.6
  • Worsened or new mental health conditions, such as depression or anxiety, which, in some cases, can also be associated with a higher risk of suicide.8,9

It’s important to understand that fentanyl can typically be used safely under a physician’s supervision, but due to its euphoric effects, fentanyl, even if taken as prescribed, comes with a high potential for dependence and addiction.3,7 One of the most serious adverse effects of fentanyl is overdose, because it can be deadly.1

Overdose can occur when a person takes enough fentanyl to cause serious and potentially life-threatening symptoms.3 People who use fentanyl should understand that it only takes a very small amount of fentanyl to cause overdose, which makes it so dangerous.1 People who are dependent, chronically use fentanyl, or misuse fentanyl can have a higher risk of overdose.10

Fentanyl Overdose

A fentanyl overdose is a medical emergency. If you think someone is overdosing, you should call 911 immediately and then administer naloxone (Narcan) if available.1 In addition, you should put the person on their side to prevent choking, try to keep them awake and breathing, and remain with them until emergency medical help arrives.1

Fentanyl is considered safe and effective when taken as prescribed by a physician as pain medication, but a variety of factors can impact the risk of overdose, such as:

  • Chronic fentanyl use.11
  • Having a breathing condition.7
  • Taking fentanyl for the first time.7
  • Having been abstinent for a period of time and resuming fentanyl use.11
  • Taking more than prescribed (intentionally or unintentionally).11
  • Using other medications or substances, such as alcohol, benzodiazepines, heroin, cocaine, MDMA, or methamphetamine, at the same time.3,7,11
  • Misusing fentanyl in other ways, such as using illicit fentanyl.3,11

Fentanyl overdose symptoms include:1

  • Small, constricted pinpoint pupils.
  • Falling asleep or losing consciousness.
  • Slow, weak, or no breathing.
  • Choking or gurgling sounds.
  • Limp body.
  • Cold and/or clammy skin.
  • Discolored skin (particularly of the lips and nails).

Naloxone, known by brand names such as Narcan or Kloxxado, is an effective opioid overdose reversal drug that can help restore breathing.12 It is a type of drug known as an opioid antagonist, meaning it works by binding to opioid receptors, which blocks and reverses the effects of opioids.12

Naloxone comes in different FDA-approved forms, including an injectable, an auto-injector, and nasal spray.11

Naloxone is an important and necessary tool for individuals, families, first responders, and communities to help reduce opioid overdose deaths.12 It is important to remember that naloxone must be administered in a timely manner in order to save a person’s life.11

Treatment for Fentanyl Addiction

Fentanyl/opioid addiction is treated as a chronic medical condition.13 Treatment typically involves a combination of medication, counseling, behavioral therapies, and attention to associated physical, mental, social, vocational, and legal issues.3,14 As a first step toward getting into rehab, it’s a good idea to discuss your condition with your doctor to help make the most advisable treatment decisions for your situation.

Prior to starting a detox or rehab program, you will receive a comprehensive evaluation to determine your unique needs.14 It’s important for treatment to be individualized to your needs at the time of your initial evaluation; your treatment plan can be modified as necessary as you progress through treatment.14

In general, the addiction treatment process involves detox, rehab, and aftercare.13 Different treatment settings will work better for different people, depending on their needs.14

Detox involves medical supervision, medication, and medical support as you undergo withdrawal to help you remain as safe and comfortable as possible, address potential complications, and help you transition to a rehab once you have completed the detox process.14 Detox often involves the use of medications to help ease withdrawal symptoms, such as methadone, buprenorphine, or lofexidine, an FDA-approved nonopioid medication.3,15

Following detox, you may enter an inpatient rehab, which means you live onsite for the duration of treatment, or outpatient treatment, such as an intensive outpatient program (IOP) , which means you live at home and travel to a treatment center.13 Treatment should also involve dual diagnosis treatment if you have a co-occurring mental health condition (such as depression or anxiety).13 During rehab, people may continue to take opioid use disorder medications, including methadone, buprenorphine, and naltrexone, or mental health medication, for ongoing treatment and maintenance.3,14

It’s important for people to receive behavioral therapy as part of fentanyl/opioid addiction treatment in order to help them make behavioral changes related to substance use.3 This can include:3

As addiction recovery is a lifelong process, it’s important to participate in some form of aftercare, also known as continuing care, after completion of a more intense treatment program.16 Aftercare, such as 12-step or other support groups, can help you work on the skills you’ve learned during the initial phase of treatment, potentially reduce the chances of relapse, and increase the chances of long-term recovery success.16

How to Find Fentanyl Addiction Treatment Near Me

If you or a loved one are struggling with fentanyl or opioid misuse or addiction, you should know that treatment can help. Research shows that treatment can help people stop using drugs like fentanyl, stay drug-free, and become more productive in their families, at work, and in society.13

If you are interested in starting treatment or learning more about rehab, call American Addiction Centers at to speak with a caring admissions navigator, who can guide you through the process and provide more information about rehab options. Our professional and caring admissions navigators are here for you 24/7. You can also visit the treatment directory to find opioid addiction treatment near you.

Rehab for fentanyl addiction can be paid for in different ways, such as using insurance for rehab, paying out-of-pocket, using Medicare/Medicaid, asking about sliding scale plans or payment plans, taking out loans, or asking friends and family to help out. If you have insurance, you should know that mental and behavioral healthcare, including addiction treatment, is an essential health benefit under the Affordable Care Act.17 Insurance companies must provide a similar level of coverage for substance use disorder and mental health services as they do for medical and surgical types of care.17

It’s important to note that every health insurance plan is different. Some are HMOs, and you may need to use in-network providers, or PPOs, where you may pay less if you use a provider in their network.18 You may also be responsible for co-pays, deductibles (the amount of money you have to pay out-of-pocket each year before your insurance plan starts to pay), or other out-of-pocket costs.19 It’s advisable to contact your insurance carrier to verify your plan benefits. You can also instantly verify your health insurance coverage by clicking here.

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