Fentanyl Withdrawal Symptoms, Risks & Side Effects

Fentanyl stands out from other opioids due to being exceptionally potent. As effective as it is for pain management, it is also highly addictive—even when taken as prescribed. As such, it’s not uncommon to struggle with fentanyl withdrawal symptoms after quitting it.

For most people, fentanyl detox is the first step to breaking free from fentanyl dependence. However, it is often easier said than done since fentanyl withdrawal symptoms tend to be particularly intense. To successfully break the cycle of addiction and minimize the risk of relapse and potentially lethal overdose, it’s crucial to seek medical help for fentanyl withdrawal.

What Is Fentanyl?

Fentanyl is a synthetic opioid prescribed to treat severe pain, typically experienced after surgery or due to illnesses such as cancer. First synthesized by Dr. Paul Janssen in 1959 as an intravenous anesthetic, it can also be used for intraoperative anesthesia.

As the most potent opioid, fentanyl is roughly 100 times stronger than morphine and 50 times stronger than heroin. It’s available in the form of:

  • Buccal tablets (Fentora®)
  • Injection (Sublimaze®)
  • Lozenges (Actiq®)
  • Nasal sprays (Lazanda®)
  • Sublingual sprays (Subsys®)
  • Sublingual tablets (Abstral®)
  • Transdermal patches (Duragesic®)
fentanyl withdrawal detox

Like other opioids, fentanyl eases pain by interacting with opioid receptors in the central nervous system, thus preventing the brain from receiving pain signals. Besides pain relief, it can also induce euphoria, sedation, drowsiness, and relaxation, among other effects.

While it is approved for medical use by the FDA, fentanyl is also a popular—and a very dangerous street drug. Some of its most common street names are Apache, China Town, Dance Fever, Jackpot, and Murder 8.

Classified as a Schedule II controlled substance, fentanyl has a high potential for abuse and addiction. Due to its potency, it also carries a high risk of opioid overdose. Since fentanyl abuse increases the risk of developing an opioid addiction, you should always take it as prescribed by a doctor.

Common Fentanyl Withdrawal Symptoms

Fentanyl withdrawal symptoms, such as vomiting, muscle aches, and insomnia, occur when people who are dependent on or addicted to fentanyl stop taking it altogether or reduce their dosage. 

In other words, these withdrawal symptoms happen when the body is going through the fentanyl detox process and is eliminating the drug from its system. 

Like any opioid, fentanyl use can lead to tolerance, especially if you take it for a prolonged period of time. 

As the tolerance builds, you’ll need more and more fentanyl to feel its effects. Tolerance signifies that you’ve become physically dependent on fentanyl, which means you need it to maintain normal functioning. Without it, you’ll experience uncomfortable withdrawal symptoms.

The most common fentanyl withdrawal symptoms are:

  • Anxiety
  • Bone and joint pain
  • Chills
  • Diarrhea
  • Dilated pupils
  • Elevated blood pressure
  • Fentanyl cravings
  • Fever
  • Headache
  • Hyperalgesia (high pain sensitivity)
  • Increased body temperature
  • Irritability
  • Muscle aches and cramps
  • Nausea
  • Runny nose
  • Sleep disturbances
  • Stomach pain
  • Sweating
  • Teary eyes
  • Vomiting

Fentanyl withdrawal symptoms can range from mild to potentially life-threatening. In severe cases, fentanyl withdrawal can result in an opioid-induced psychosis characterized by symptoms such as hallucinations and delusions.

Tapering off fentanyl can reduce the severity of withdrawal symptoms, whereas quitting this drug “cold turkey” increases their intensity and the risk of relapse, overdose, and death. For this reason, you should never attempt going through fentanyl detox without medical supervision.

Fentanyl Withdrawal Timeline

Fentanyl Withdrawal Timeline

The fentanyl withdrawal timeline may vary from person to person, depending on the fentanyl usage method, duration, dosage, and other similar factors.

Here’s what a typical fentanyl withdrawal timeline looks like:

The first 12 hours

Fentanyl withdrawal symptoms often begin within the first 12 hours following the last dose. 

Usually, the first symptoms to appear are:

  • Flu-like symptoms (runny nose, teary eyes, headache, etc.)
  • Insomnia
  • Muscle aches
  • Sweating

Days 1–3

During this time, you may experience diarrhea, nausea, vomiting, and other uncomfortable and potentially dangerous fentanyl withdrawal symptoms. These symptoms usually peak in intensity sometime within the first 72 hours

Days 5–14

After reaching their peak, acute fentanyl withdrawal symptoms begin to ease and usually subside within the first two weeks after taking the last dose. 

However, psychological withdrawal symptoms—cravings, depression, anxiety, and the like—often become more intense during this time, which means you may still be at a high risk of relapse. Some of these symptoms can last weeks, months, or even years.

How Long Do Fentanyl Withdrawal Symptoms Last?

How Long Do Fentanyl Withdrawal Symptoms Last?

Fentanyl withdrawal symptoms usually last up to two weeks, though these symptoms may last much longer for some people. If your withdrawal symptoms last weeks or longer, it may be a sign of post-acute withdrawal syndrome (PAWS).

The duration of fentanyl withdrawal symptoms generally depends on various individual factors. These include the extent of fentanyl usage (how long, how frequently, at what dose, and in which formulation you’ve been taking the medication), age, metabolism, overall health, and so on.

As a general rule, the better your body breaks down fentanyl, the less time you’ll need to detox from fentanyl. 

For example, someone with liver problems who has been taking fentanyl for a year will most likely suffer from fentanyl withdrawal symptoms for a longer time than someone without health problems who has been taking fentanyl for a couple of months.

How to Manage Fentanyl Withdrawal Symptoms

Managing fentanyl withdrawal symptoms on your own is not only difficult but also dangerous, which is why it’s best to seek professional fentanyl withdrawal treatment.

Every person experiences fentanyl withdrawal differently. While for some it feels similar to the flu, others suffer from excruciating pain. In any case, the withdrawal process can be very dangerous (e.g., it can lead to severe dehydration). 

Not to mention, it makes you vulnerable to relapse. It’s not uncommon for people to turn to fentanyl to soothe their suffering and discomfort, but this can quickly lead to a lethal overdose due to decreased tolerance to the drug. You may even overdose on fentanyl by taking your usual dose since your body is no longer used to the drug.

To go through the fentanyl detox process safely and make a lasting recovery from opioid addiction, you should seek professional help for fentanyl withdrawal. However, it’s crucial to make an informed decision when choosing a fentanyl withdrawal treatment, as not all of them are equally safe and effective.

Dangers, Risks, and Side Effects of Fentanyl

The two greatest dangers associated with fentanyl are addiction and overdose.

Like any opioid, fentanyl alters brain chemistry, suppressing the natural production of endorphin receptors while increasing that of opioid receptors. This means that anyone taking it—even those who take it exactly as prescribed—is at risk of developing a fentanyl addiction.

Some common fentanyl addiction symptoms include:

  • Experiencing strong fentanyl cravings
  • Showing less or no interest in previously enjoyed activities
  • Neglecting family, work, and other responsibilities
  • Feeling unable to stop using fentanyl
  • Continuing to use fentanyl despite its negative effects

Moreover, as a very potent opioid, fentanyl carries a high risk of opioid overdose. 

According to Centers for Disease Control and Prevention data, over 82,000 people died from an opioid overdose in 2022. Slightly above 74,000 of these deaths were related to synthetic opioids such as fentanyl.

fentanyl withdrawal detox

Unfortunately, more and more people die from fentanyl-related overdoses every year. Such deaths increased by 282% between 2016 and 2021.

The risk of a potentially lethal fentanyl overdose may be further heightened by mixing it with other substances, including alcohol. Taking fentanyl after a period of abstinence also increases this risk due to reduced tolerance to the drug.

Illicit drugs are particularly dangerous, as they may be laced with fentanyl without your knowledge. This makes it nearly impossible to gauge how much of the drug you can take without overdosing on it.

Besides that, fentanyl can also cause various side effects. The most common ones include:

  • Appetite loss
  • Constipation
  • Drowsiness
  • Fatigue
  • Headache
  • Lightheadedness
  • Nausea
  • Skin rashes
  • Vomiting

Fentanyl can also lead to life-threatening breathing problems, including respiratory depression. Because of this, it may not be a good option for people with pre-existing respiratory issues. 

Rapid Detox for Opioid Addiction 

Advanced rapid detox is a medical treatment that usually involves general anesthesia and opioid antagonists to quickly cleanse opioids, including fentanyl, from the body. Rapid detox under sedation can help minimize the intensity of fentanyl withdrawal symptoms, but there’s no evidence that it helps people make a lifelong recovery.

Many patients relapse after rapid fentanyl detox, as it only manages the symptoms of addiction without addressing its biological cause – the changes in brain chemistry. Since rapid fentanyl detox reduces opioid tolerance, relapse can result in a potentially fatal overdose. As such, the disadvantages of rapid detox, including its high cost, often outweigh its benefits.

ANR Opioid Treatment – Treating Opioid Dependency with ANR 

Accelerated Neuro-Regulation (ANR) is the only medical treatment that is shown to restore the endorphin-receptor balance in individuals struggling with fentanyl dependency.

What makes the ANR treatment unique from rapid detox and other opioid dependency treatments is that it tackles the biological root cause of dependency instead of simply counteracting its symptoms. As a result, it eliminates fentanyl dependency along with cravings and withdrawals.

Additionally, the ANR treatment offers a personalized approach to overcoming fentanyl addiction, which maximizes its safety. Our experienced medical professionals will evaluate your specific needs and medical history and tailor your treatment accordingly. 

While most treatments need weeks to take effect, ANR allows patients to recover from fentanyl dependency in just a few days. Most patients enjoy healthy living without any risks of further symptoms or relapse after the treatment in one of our centers.

ANR Clinic offers healthcare facilities in:

  • DeSoto Memorial Hospital, Arcadia, Florida
  • ANR Europe Thun, Switzerland
  • New Vision University Hospital, Tbilisi, Georgia
  • Innovate Intelligent Place, Goiânia, Brazil

Contact us today for a free, 100% confidential consultation!

Key Takeaways

If you’re struggling with fentanyl addiction, keep in mind that seeking professional help can not only help you overcome opioid dependence safely and effectively but also save your life. 

The last thing you should do is quit it on your own. Fentanyl withdrawal symptoms can be so intense that you may accidentally overdose on this drug in an attempt to ease your pain or suffering.

Now, let’s reiterate the key points we covered:

  • Fentanyl is an extremely potent opioid that carries a high risk of abuse, addiction, and overdose.
  • Fentanyl withdrawal symptoms occur in people who have developed fentanyl dependence or addiction after they quit or cut back on fentanyl.
  • The most common fentanyl withdrawal symptoms are nausea, muscle pain, runny nose, sweating, vomiting, and difficulty sleeping.

Fentanyl Withdrawal Detox FAQ

The main withdrawal symptoms of fentanyl are:

  • Fentanyl cravings
  • Flu-like symptoms (runny nose, headache, etc.)
  • Nausea
  • Diarrhea
  • Sweating
  • Chills
  • Muscle aches
  • Difficulty sleeping

To safely taper down fentanyl, you should work with your doctor to create a fentanyl tapering schedule. Tapering off fentanyl is a long process that often takes months. More often than not, your doctor will reduce your dose by 5–20% each month until you can safely quit taking fentanyl.

You can cope with fentanyl withdrawal by taking care of your physical and mental health, which includes exercising, meditating, sticking to a consistent sleeping schedule, and so on. That said, you should never quit fentanyl without medical supervision, as it can be dangerous and lead to a potentially life-threatening relapse.

Yes, even small doses of fentanyl can be lethal since this opioid is exceptionally potent. Synthetic opioids like fentanyl are the leading cause of opioid-related overdose deaths. You should never take more fentanyl than prescribed or mix it with other substances, such as alcohol, sedatives, or benzodiazepines, as this increases the risk of a fentanyl overdose.

The side effects of fentanyl are similar to those of other opioids and include nausea, vomiting, dizziness, excessive sleepiness, headache, and constipation. If you experience any of these side effects, inform your doctor about them—especially if they aren’t improving.

Fentanyl stays in your system for 22 hours on average. However, blood tests can detect it for up to 72 hours after the last dose, whereas urine tests can find traces of fentanyl in your system for up to three days. Hair follicle tests, meanwhile, have a 3-month fentanyl detection window.

ANR stands for Accelerated Neuro-Regulation, a revolutionary opioid addiction treatment that addresses the underlying causes of opioid dependence. By reversing the opioid-induced changes in the brain, the ANR treatment has helped over 24,000 people worldwide beat opioid addiction.

Reclaim your life with the revolutionary ANR treatment.

Dr. Andre Waismann

Dr. Waismann identified the biological roots of opioid dependency, Since then he has successfully treated more than 24,000 patients worldwide that are struggling with opioid addiction.


Throughout his career, he has lectured and educated health professionals in dozens of countries around the world to this day.

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