Fentanyl withdrawal symptoms are similar to those people experience when they stop taking other opioids, but some symptoms can linger. Symptoms typically start a few hours after the last dose and peak within the first few days. Some people experience post-acute withdrawal symptoms, meaning symptoms that persist for several weeks or months.

Fentanyl is a synthetic opioid used by doctors to treat severe pain. It is much stronger than morphine, and fentanyl addiction can develop quickly. The high potency of fentanyl means there’s a high risk of overdose. In 2022, U.S. Drug Enforcement Administration lab testing found that six out of 10 fentanyl-laced fake prescription pills contained a potentially lethal dose of the drug. It’s risky to stop taking fentanyl abruptly because withdrawal symptoms can be severe and the risk of relapse is high. A residential medically supervised detox helps reduce the risk of relapse and ease withdrawal symptoms while your brain relearns how to operate without the drug.

How Fentanyl Withdrawal Differs From Other Opioids

Fentanyl is about 100 times stronger than morphine and up to 50 times stronger than heroin. It’s also a faster-acting drug than morphine. These properties make it effective for short-term pain relief in medical settings. However, the high potency of the drug means that it carries an increased risk of overdose.

Fentanyl is also stored in the body’s fat tissue with repeated use, which may make the timing and course of withdrawal less predictable than with other opioids. It can also make starting medication more complicated, which is one reason fentanyl withdrawal is best managed with medical support. Learn more about the differences between heroin and fentanyl addiction.

Fentanyl Withdrawal Timeline and Common Symptoms

It’s common for people to start feeling fentanyl withdrawal symptoms within the first 8 to 24 hours after the last use of the drug. Those symptoms gradually become more severe and typically peak within the first few days of quitting.

Symptoms of this initial acute phase of withdrawal can include:

  • Anxiety
  • Nausea or vomiting
  • Insomnia
  • Diarrhea
  • Sweating
  • Increased nasal discharge
  • Tremors
  • Increased heart rate

These symptoms typically persist for between 4 and 10 days and start to become less severe after that. It’s important to have medical supervision during the first week of withdrawal to help prevent serious complications.

Some symptoms, such as anxiety, sleep disturbances, fatigue, low mood and irritability, can persist for several months. Clinicians refer to these symptoms as post-acute withdrawal syndrome. Not everyone who quits fentanyl experiences these symptoms, and their severity can vary. With sustained abstinence, most people find these symptoms eventually fade.

Why Fentanyl Withdrawal Requires Medical Supervision

While opioid withdrawal is rarely life-threatening on its own, it can lead to serious complications. One common issue during withdrawal is dehydration due to the combination of sweating, vomiting and diarrhea.

Because fentanyl slows heart rate and breathing, the rebound increase in heart rate and blood pressure during withdrawal can strain the cardiovascular system, especially for people with existing heart conditions. A medically supervised detox helps manage these issues and reduce the risk of complications.

There’s also a serious risk after withdrawal ends. Tolerance drops quickly once someone stops using fentanyl, so returning to a previous dose can cause an overdose. Supervised detox, followed by ongoing treatment, helps reduce the chance of relapse during this vulnerable period.

Medication-Assisted Fentanyl Withdrawal

One way of helping people through the first few days of a fentanyl detox is medication-assisted treatment (MAT). Buprenorphine can help reduce cravings and ease the worst of the withdrawal symptoms. When you’re admitted for fentanyl withdrawal, your care team will assess your history and current symptoms, which may include a drug screen, before deciding which medications can help.

With fentanyl, timing matters. Starting buprenorphine too soon can trigger precipitated withdrawal, a sudden and intense onset of symptoms. To reduce that risk, clinicians may begin with a very low dose and increase it gradually while monitoring your response, helping your brain chemistry adapt to the absence of the drug.

Fentanyl Post-Acute Withdrawal Syndrome (PAWS)

Some people who stop taking fentanyl experience sleep disruption, mood swings, anxiety or cognitive impairment that lasts long after the acute withdrawal symptoms have passed. These symptoms can fluctuate in severity during the healing process.

The combination of long-term symptoms and fluctuating severity can make post-acute withdrawal syndrome a significant risk factor for relapse. It’s important to understand that the symptoms are typically temporary and that, with time and continued abstinence, your brain’s chemistry can recover, although the timeline varies from person to person.

Staying in touch with the team at Sunlight Recovery and working with peer support groups in Florida can reduce the risk of relapse.

Fentanyl Detox at Sunlight Recovery

At Sunlight Recovery, we provide medically supervised detox for people concerned about fentanyl withdrawal symptoms at our Boca Raton campus. Our care team has experience helping people recover from alcohol and drug addiction. We assess each client individually and may offer buprenorphine and other medications, such as clonidine, to ease the withdrawal process, along with symptom management, hydration and monitoring to support a safe withdrawal.

Our support doesn’t end when detox does. Many clients continue into residential treatment, then step down to outpatient care at our Deerfield Beach campus. Ongoing therapy and our alumni program help people manage post-acute withdrawal symptoms and stay connected to recovery. Sunlight Recovery is accredited by CARF International and The Joint Commission and licensed by Florida DCF.

Call our 24/7 admissions line at (855) 625-6684. Every call is confidential, with no obligation.

Frequently Asked Questions About Fentanyl Withdrawal



Acute symptoms usually begin 8 to 24 hours after the last use, peak within the first few days and begin to ease after about 4 to 10 days. Some people experience post-acute symptoms, such as anxiety and sleep problems, for weeks or months.


Going through a medically supervised fentanyl detox helps you manage withdrawal symptoms safely and reduces the likelihood of a relapse. Contact Sunlight Recovery’s admissions team to talk through whether a supervised detox makes sense for your circumstances.


No. Some people experience fentanyl withdrawal symptoms for weeks or months after detox, which is known as post-acute withdrawal. With continued abstinence, these symptoms typically fade over time. Peer support groups can help you stay the course during the post-acute withdrawal period.


While quitting fentanyl cold turkey is possible in some cases, it is very difficult, and there is a risk of serious complications. The risk of relapse is higher when quitting cold turkey because many people find the withdrawal symptoms difficult to manage. Seek professional advice before you stop taking fentanyl or other opioids.


Attending an inpatient facility for a supervised fentanyl detox program can help ensure a safe withdrawal and reduce the likelihood of a relapse. An inpatient detox program includes medically supervised withdrawal, along with therapy and other support to help clients withdraw safely and maintain their recovery once they leave the facility.

Sunlight Recovery Is Here to Help on Your Detox Journey

If you’re struggling with fentanyl addiction, you don’t have to go through it alone. As an in-network provider, Sunlight Recovery works with many insurance plans. Call our 24/7 admissions line at (855) 625-6684 or contact Sunlight Recovery to take the first step toward recovery. Every call is confidential, with no obligation.