Fentanyl Withdrawal & Detox

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By: Renaissance Recovery

Clinically Reviewed by: Diana Vo, LMFT

Last Updated: 7/1/2021

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Authored By: Joe Gilmore

Table of Contents

Fentanyl is a powerful synthetic opioid that is also highly addictive, but the fentanyl withdrawal and detox process is similar to that of other opioids.

According to recent SAMHSA data, the number of people with opioid use disorder is on the decline in the US, but fentanyl and other synthetic opioids remain a deadly threat.

Understanding Fentanyl Withdrawal

Any use of fentanyl raises the following risks:

  • Tolerance
  • Dependence
  • Fentanyl abuse
  • Fentanyl addiction

Like with other opiates, tolerance can easily develop. This means you will need to take more fentanyl to achieve the same effects, or you will need to take the drug more frequently. Tolerance to fentanyl builds rapidly.

Once physical dependence sets in, you will experience withdrawal symptoms when the drug is no longer in your system. These symptoms typically start around 12 hours after the last dose, lasting for a week or so.

NIDA (the  National Institute on Drug Abuse) defines addiction as a chronic and relapsing condition involving more than physical dependence. Addiction to fentanyl is characterized by compulsive drug-seeking and drug-taking behaviors despite clearly negative outcomes. For someone with a fentanyl addiction – clinically described as opioid use disorder – obtaining and using the substance becomes the primary driver in life.

The appropriate treatment for fentanyl addiction depends on the scope and severity of the problem.

Just like any opioid use disorder, the treatment for fentanyl addiction depends on the severity of the problem. The same applies to fentanyl withdrawal and detox.

Fentanyl Withdrawal Timeline

With opioid withdrawal, the first withdrawal symptoms usually present from 8 to 36 hours after your last dose of the drug. 

The onset of fentanyl withdrawal hinges on the dosage being used as well as the frequency of use.

Once symptoms start manifesting, fentanyl withdrawal typically unfolds according to the following timeline.

Day 1 of fentanyl detox

Fentanyl is a short-acting opioid like heroin and codeine. This means withdrawal symptoms usually present anywhere from 8 to 24 hours after the last dose. With a long-acting opioid like oxycodone extended-release tablets, by contrast, withdrawal symptoms appear from 24 to 48 hours after the last dose.

During the first day of fentanyl withdrawal, you may experience any or all of the following:

  • Powerful cravings for fentanyl
  • Anger
  • Aggression
  • Irritability
  • Muscular aches
  • Muscular pains
  • Headaches
  • Disrupted sleep patterns
  • Appetite loss

Day 2 of fentanyl detox

The second day of fentanyl detox sees a continuation of the above withdrawal symptoms, as well as the following negative effects:

  • Insomnia
  • Excessive sweating
  • Runny nose
  • Upset stomach
  • Panic attacks

Day 3 of fentanyl detox

Fentanyl withdrawal symptoms will normally peak on the third day of detox. This applies to all short-acting opioids.

The most pressing symptoms during this acute phase of opioid withdrawal include:

  • Nausea
  • Vomiting
  • Diarrhea

You can also expect the above symptoms to persist during the third day of fentanyl detox.

Day 4 of fentanyl detox

As the most acute phase of fentanyl withdrawal is complete, the following symptoms may linger:

  • Fatigue
  • GI disturbance
  • Cramps
  • Shivering
  • Enlarged pupils

Day 7 of fentanyl detox

After a week of fentanyl detox, all withdrawal symptoms should start to subside. It may take longer for sleep patterns to normalize. It is also commonplace for fatigue to linger, as well as spells of depression.

In the event of PAWS (post-acute withdrawal syndrome), symptoms can persist for several months after discontinuing the use of fentanyl. The most common effects of PAWS are as follows:

  • Depressed mood
  • Strong cravings for opioids
  • Fatigue
  • Disrupted sleep patterns
  • Irritability

How Long Does Fentanyl Withdrawal Last?

While fentanyl detox normally lasts for between 5 and 7 days, some people find withdrawal occurs in more or less time than this.

Every detox is unique, so it is vital to undergo a thorough evaluation to determine how long you will need for fentanyl detoxification.

An image of a sign at a medical detox center | Fentanyl withdrawal

Withdrawal Symptoms of Fentanyl

Taking opioids long-term, even when taken as directed with a prescription, quickly causes your body to become desensitized to opioid’s pain-relieving and rewarding effects. Tolerance quickly builds, requiring you to increase the amount or frequency of fentanyl doses to generate the same effects.

Sustained opioid abuse triggers changes to the function of some nerve receptors in the brain. With your nerve receptors becoming dependent on opioids, this altered brain chemistry causes the manifestation of withdrawal symptoms in the absence of opioids.

From prescription opioid painkillers through to heroin and fentanyl, opioid withdrawal symptoms are broadly similar, including:

  • Vomiting
  • Nausea
  • Diarrhea
  • Elevated blood pressure
  • Anxiety
  • Insomnia
  • Raised body temperature
  • Chills
  • Sweating
  • Racing heart
  • Muscle pain
  • Bone pain


Opioids and opiates are not typically associated with full-blown psychosis. That said, some people undergoing fentanyl withdrawal may experience hallucinations, delusions, or other psychotic symptoms.

To prevent the occurrence of psychotic symptoms while also minimizing some of the other unpleasant side effects of fentanyl withdrawal, seek medical assistance and consider a medically supervised detox.

Fentanyl Detox

The fentanyl detox process involves removing toxic substances and toxic metabolites safely from the system.

With fentanyl withdrawal, detox is normally performed in a licensed medical detox center or substance abuse treatment center.

Detox can take place in a standalone capacity or as the precursor to residential rehab. With around-the-clock medical care and mental health support, all complications of fentanyl withdrawal can be monitored and minimized.

Medications can help alleviate many of the more intense opioid withdrawal symptoms, and some medications can also reduce the cravings you will experience for fentanyl during detox.

How Long Does it Take to Detox from Fentanyl?

If you’re still wondering how long does it take to detox from fentanyl, this depends on the following variables:

  • How much fentanyl is in your system
  • Quantity of fentanyl being abused
  • Route of delivery (patch or injection)
  • Any other substances in your system

Fentanyl detox will last from 4 days to 20 days or more after the last use of fentanyl.

An image of a beach next to a medical detox center | Fentanyl withdrawal

Fentanyl Rehab at Renaissance Recovery

​​Fortunately and despite its strong abuse profile, fentanyl addiction typically responds favorably to an evidence-based combination of medications and psychotherapies.

During fentanyl detox, medications can streamline the intensity of the withdrawal process and help with the drug taper, while counseling and talk therapy sessions will help you identify what triggers you to use opioids like fentanyl despite the negative consequences.

At Renaissance, we provide the following outpatient services for substance use disorders like fentanyl addiction:

  • Outpatient program (OP)
  • Intensive outpatient program (IOP)
  • Partial hospitalization program (PHP)
  • Remote intensive outpatient program (virtual IOP)

For most cases of fentanyl addiction, the structure and support of a PHP works best. This is the most intensive form of addiction treatment outside of residential rehab.

To start detoxing from fentanyl safely and as comfortably as possible, reach out to Renaissance today at 866.330.9449.

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