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How Long Does Fentanyl Withdrawal Last?

Peter Manza, PhD profile image
Reviewed By Peter Manza, PhD • Updated Feb 24, 2024 • 13 cited sources

Acute fentanyl withdrawal lasts for about a week or so. You will feel sick, restless and cravings for more drugs. However, some people experience mental health symptoms and cravings that linger for a month or longer. 

Understanding Fentanyl Withdrawal 

Fentanyl is a prescription medication used for acute pain that won’t respond to other opioid drugs. It’s also the substance of choice for dealers who hope to make a very addictive drug for a quick profit. 

Fentanyl is an opioid that’s 50 to 100 times more potent than morphine.[1] It works by latching to receptors inside the brain, prompting dopamine release. People who use fentanyl may feel an intense high, followed by significant sedation. Some overdose on fentanyl, as they weren’t expecting such a strong drug.

Dealers mix fentanyl with drugs like heroin, cocaine and methamphetamine.[1] Nearly 88% of opioid overdose deaths in 2021 involved synthetic opioids like fentanyl.[2] Some people never get the chance to develop an opioid use disorder (OUD), as they overdose first. 

People can — and often do — develop OUD related to fentanyl use. The drug is so powerful, and the changes it makes are so profound, that it’s easy to keep using it and hard to stop. 

When brain cells are accustomed to fentanyl, the person may feel as though they can only function properly when the drug is present. Quit abruptly, and you will feel sick until your brain adjusts to sobriety or you ease your symptoms with Medication for Addiction Treatment (MAT).

Common Fentanyl Withdrawal Symptoms

Common Fentanyl Withdrawal Symptoms

While every person is different, most fentanyl users experience similar problems when they quit the drug abruptly. Common withdrawal symptoms associated with fentanyl include the following:[3]

  • Muscle and bone pain
  • Restlessness and agitation
  • Insomnia
  • Cold flashes with goosebumps
  • Diarrhea
  • Nausea and vomiting
  • Dilated pupils
  • Sweating
  • Runny nose and watery eyes
  • Cravings for fentanyl

Fentanyl Withdrawal Timeline 

Like all short-acting opioids, fentanyl can cause withdrawal symptoms that begin between 8 and 24 hours after your last dose.[4] The entire withdrawal process, if you don’t use MAT, will last between 4 and 10 days.[4] 

A typical withdrawal process is split into the following three phases:[3]

  • Early withdrawal: Symptoms like agitation, muscle aches and insomnia appear. 
  • Late withdrawal: Gastrointestinal problems, including severe diarrhea, take hold. 
  • Recovery: Cravings persist, but physical symptoms fade. 

Typical Withdrawal Timeline

Within 8 and 24 hoursEarly withdrawal symptoms like agitation, aching muscles and insomnia develop.
Day 2Early withdrawal symptoms intensify.
Day 3Early withdrawal signs continue, and it’s harder to tolerate them due to longstanding insomnia.
Day 4Late-stage symptoms, including gastrointestinal problems, begin.
Day 5Abdominal problems intensify, and dehydration can begin if people aren’t provided adequate treatment.
Day 6Gastrointestinal problems intensify, and they’re accompanied by strong drug cravings.
Day 7Abdominal cramping and diarrhea begin to fade. You may be able to sleep more regularly.
Day 8Physical and mental health symptoms ease, but drug cravings persist.
Day 9You’re feeling much more like yourself, but your thoughts are consumed with buying and taking more drugs.
Day 10Physical symptoms decrease, but you may still crave drugs.

Is Fentanyl Withdrawal Dangerous?

Opioid withdrawal is sometimes described as flu-like.[9] However, experts say untreated withdrawal episodes can be life-threatening.[10]

Acute opioid withdrawal can cause simultaneous vomiting and diarrhea.[3] Your body loses a significant amount of fluids and electrolytes during these episodes. Without enough liquid, your brain cells can’t function properly, and your organs can shut down. While dehydration can be treated, people who move through at-home detox may not get the help they need to recover.

Withdrawal is also not a treatment for OUD.[4] People who complete withdrawal and don’t enter a treatment program are likely to return to drugs. When they do, they can overdose. One study of 178,749 people discharged from treatment programs found that death rates  were highest in the first 28 days upon leaving treatment.[11]

Even short periods of sobriety can lower opioid tolerance.[12] A dose that was safe before the person entered rehab could be fatal when they leave it. While anyone who is using fentanyl should get help to quit, they should stick with treatment to minimize the risk of relapse.

Post-Acute Withdrawal Syndrome (PAWS)

Some people experience lingering withdrawal, known as post-acute withdrawal syndrome (PAWS).

PAWS involves symptoms that appear within four to six weeks of quitting drugs, and they can last for six months to two years. Researchers say PAWS hasn’t been studied as much as standard withdrawal syndromes, but an estimated 90% of people with OUD experience some level of PAWS.[13]

PAWS involves symptoms like the following:[5]

  • Anxiety and depression
  • Insomnia
  • Fatigue and lethargy
  • Irritability and mood swings
  • Difficulty concentrating and memory problems
  • Cravings for the drug
  • Reduced appetite and gastrointestinal problems
  • Sensory disturbances, such as tingling or numbness

PAWS can be challenging to manage, increasing the risk of relapse because taking an opioid will immediately quell the symptoms. This increases the temptation to return to use.

To manage PAWS, a combination of support and treatment interventions, such as counseling, MAT and support groups, are recommended.

It is important to seek professional help to manage the experience without a potentially deadly relapse. If you’re tempted to return to drugs to make your symptoms stop, contact your treatment team and ask for help.

Factors That Affect the Length & Severity of Withdrawal Symptoms

No two people’s experiences in life, physical health or even their relationship to fentanyl will be the same. The characteristics of each of these issues will impact the duration and severity of fentanyl withdrawal symptoms.

Researchers say factors associated with opioid withdrawal severity include the following:[6]

  • Sex: Women tend to have stronger symptoms than men do. 
  • Other drugs used: People who mix cocaine with opioids tend to have stronger symptoms than others do. 
  • Route of administration: People who inject drugs usually have stronger symptoms than others who use the drug by other routes of administration (e.g., insufflation) do.

Other factors commonly associated with more severe symptoms include the following:[7-9]

  • Dosage: Taking higher doses of fentanyl will usually result in more intense withdrawal symptoms.
  • Age and health. Older people or those with underlying medical conditions may experience more severe withdrawal symptoms or require longer recovery periods than younger, healthier individuals.
  • Mental health. Pre-existing mental health conditions may translate into a more intense experience with withdrawal symptoms, increasing the risk of relapse.

Medical Detox for Fentanyl Withdrawal 

MAT involves using pharmaceutical solutions to amend chemical imbalances and ease withdrawal symptoms. 

With MAT, fentanyl detox is far more comfortable. Even with medication, you may experience withdrawal symptoms. However, most people can function well enough to attend group therapy sessions, work and care for other aspects of their lives.

Without medication, fentanyl withdrawal symptoms can feel like a terrible flu, complete with nausea, vomiting and insomnia. It is virtually impossible to function in the throes of fentanyl withdrawal without medication and support.

Medications typically used in MAT programs include the following:

  • Methadone: This medication latches to opioid receptors and can buy the brain and body time to recover from the damage done by fentanyl. 
  • Buprenorphine: This medication is designed for at-home use, and it also latches to opioid receptors.

Some MAT programs also provide medications to ease acute withdrawal symptoms, such as clonidine. This medication relaxes blood vessels and can lower blood pressure. 

Is MAT Right for Me?

Each person’s experience is different, but no one can escape fentanyl withdrawal without discomfort unless the person undergoes treatment, especially MAT.

If you or someone you love is experiencing withdrawal symptoms due to fentanyl detox, it is important to connect with a medical professional for MAT. 

Medications can ease symptoms and help you avoid potential medical complications, especially if underlying chronic illnesses are present. If you attempt to detox on your own, relapse is highly likely.

Bicycle Health offers MAT via telemedicine appointments. Meet your team via your computer or phone, and pick up your prescription at a pharmacy near you. Work with experts without ever leaving your home, and know you’re always connected to help whenever you need it. 

Reviewed By Peter Manza, PhD

Peter Manza, PhD received his BA in Psychology and Biology from the University of Rochester and his PhD in Integrative Neuroscience at Stony Brook University. He is currently working as a research scientist in Washington, DC. His research focuses on the role ... Read More

  1. Fentanyl drug facts. National Institute on Drug Abuse. Published June 2021. Accessed October 13, 2023.
  2. Drug overdose deaths. Centers for Disease Control and Prevention. Published August 22, 2023. Accessed October 13, 2023. 
  3. Opiate and opioid withdrawal. U.S. National Library of Medicine. Published March 30, 2022. Accessed October 13, 2023. 
  4. Withdrawal management. Clinical Guidelines for Withdrawal Management and Treatment of Drug Dependence in Closed Settings. Published 2009. Accessed October 13, 2023. 
  5. Post-acute withdrawal syndrome (PAWS). Semel Institute for Neuroscience and Human Behavior. Accessed October 13, 2023. 
  6. Bluthenthal RN, Simpson K, Ceasar RC, Zhao J, Wenger L, Kral AH. Opioid withdrawal symptoms, frequency, and pain characteristics as correlates of health risk among people who inject drugs. Drug and Alcohol Dependence. 2020;211:107932. 
  7. Hartwell KJ, Tolliver BK, Brady KT. Biologic commonalities between mental illness and addiction. Primary Psychiatry. 2009;16(8):33-39. 
  8. Reidenberg MM. Drug discontinuation effects are part of the pharmacology of a drug. Journal of Pharmacology and Experimental Therapeutics. 2011;339(2):324-328. 
  9. Gupta M, Gokarakonda SB, Attia FN. Withdrawal syndromes. StatPearls. Published 2020. 
  10. Shah M, Huecker M. Opioid withdrawal. Stat Pearls. Published July 21, 2023. Accessed January 19, 2024.
  11. Maughan B, Becker E. Drug-related mortality after discharge from treatment: A record-linkage study of substance abuse clients in Texas, 2006-2012. Drug and Alcohol Dependence. 2019;204: 107473.
  12. What is Opioid Tolerance? Providers Clinical Support System. Published June 10, 2021. Accessed January 19, 2024.
  13. Alsheikh, M. Post-acute withdrawal syndrome: The major cause of relapse among psychoactive substances addicted users. Archives of Pharmacy Practice. 2021;12(4):91-97.

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