Fentanyl Withdrawal Timeline

05 Mar Fentanyl Withdrawal Timeline

Table of Content

Developed in the 1960s, Fentanyl is a painkiller engineered to treat severe cases of pain. Since its inception, it has taken many different roles in medicine and eventually, due to the opioid crisis, transformed into the deadliest opioid offered by Big Pharma and replicated in the black market. Now Fentanyl is coming into the US through dangerous drug labs and is causing havoc through overdoses and fentanyl laced drugs. If someone you know is suffering from fentanyl drug addiction, it’s imperative that usage stops and they get immediate help from a Georgia drug rehab facility right away. This highly addictive opioid is responsible for thousands of fentanyl overdoses across the US and is, by all accounts, the most dangerous drug to be addicted to.

If you’re here to understand what’s to come from fentanyl detox, below we will discuss the fentanyl withdrawal timeline, common fentanyl facts, and highlight what’s to be expected on the road to recovery.

How Long Does It Take?

The unfortunate reality of opioid addiction is that objective withdrawal timelines do not exist. The extent of withdrawal and the detox treatment depend heavily on:

  • The user’s biological profile
  • Length of use
  • Form of administration (ingested orally or injected intravenously)
  • The health & age of the user

With that being said, there are certain commonalities that run a thread through the detox process. These can be used to paint an estimated withdrawal timeline.

How Long Until Withdrawal Kicks In?

The onset of fentanyl withdrawal symptoms depends largely on the half-life of the specific brand, and the amount last ingested. The type of administration can also be a factor. For instance, someone that takes a pill orally will have a less severe onset than someone who injects fentanyl intravenously.

Fentanyl’s half-life is broken down into four categories, and they’re all measured in hours:

  • Fentanyl (buccal), 3.22-6.43
  • Fentanyl (injection), 3.65
  • Fentanyl (sublingual tablet), 5.02-13.5
  • Fentanyl (transdermal), 16-25

By this data, you can then estimate when withdrawal symptoms will arise. Injecting the drug will have the lowest half-life, while taking it as a transdermal will yield the highest.

12-48 Hours | Phase One

Clinicians, doctors, and experts may agree on the generalized timeline of phase one. As a rule of thumb, the timeline starts when the withdrawals set in, plus an additional 24 hours afterward. In this phase, the autonomic nervous system (ANS) struggles to regain balance. The hyperactive activity of the neurons in this region—caused by extended opioid use—causes a host of both neurophysiologic and somatic withdrawal symptoms.

The most common symptoms experienced in this initial phase include but are not limited to:

  • Lacrimation: the flowing of tears and general leakage
  • Rhinorrhea: the flooding of the nasal cavity with mucus fluid
  • Excessive sweating: both hot and cold flashes, fluctuating drastically
  • Anxiety: as the brain tries to regulate its natural chemistry, it lacks the ability to support systems responsible for anxiety-management
  • Insomnia & Restlessness: a disrupted sleep cycle and the development of insomnia are not uncommon in this initial period of detoxification
  • Nausea: nausea and a loss of appetite are common symptoms of phase one
  • Vomiting: often accompanying nausea, it can be difficult to retain food or liquid in the stomach
  • Muscle aches: the absence of the opiate painkiller can cause one to experience pain at an intensity stronger than before, often felt in the bones and muscles
  • Involuntary movements: twitching, spasms, and similar involuntary movements are common as the body attempts to adjust to the absence of opioids  

Unfortunately, these symptoms will persist into the second phase.

2-7 Days | Phase Two

Typically, in the second phase of fentanyl withdrawal, the symptoms from phase one will continue to persist and increase in severity. But only in the initial days will the patient experience these acute opioid withdrawal symptoms. This means that, dependent on the user, in the first half of phase two they will feel an influx in symptoms, but by the second half the severity will wane. By the time they’re at the end of phase two, the symptoms are less excruciating compared to what they have encountered thus far. Additionally:

  • Diarrhea & Vomiting: a huge problem during phase two, diarrhea and vomiting can persist and then dehydrate the user. This is where the largest health risk lies, being that the body—often already malnourished—will dehydrate to an extent that is damaging to certain organ systems. One of the main purposes of physicians during fentanyl detox is to ensure the patient remains hydrated
  • Emotional Volatility: as the brain tries desperately to restore balance, mood swings, depression, anxiety, waves of panic, and a host of other psychological symptoms can arise. This is only common sense, seeing as fentanyl has flooded the brain with dopamine, damaged mu, delta, and kappa opioid receptors, and has stimulated the central nervous system
  • Hypotension: the patient begins to experience a drop in blood pressure
  • Bradycardia: although slightly less common, the heart can begin to beat slower and slower
  • Mydriasis: the pupils can become noticeably dilated
  • Psychosis: another rare symptom—and often only triggered by an underlying mental illness dormant or present before the introduction of opioids—psychosis can occur in the form of paranoia, delusion, and hallucinations

By the end of phase two, typically the patient feels drastically better than he or she did at the beginning of detox. Normal body systems begin to regain their functionality, the severity of the symptoms decrease, and finally the patient is able to experience bouts of clarity.

1 Week and Beyond | Phase 3

While most fentanyl withdrawal symptoms will begin to dissipate, the few that commonly persist are:

  • An increased sensitivity to pain: opioids attach to opioid receptors, thus blocking pain pathways. Therefore, once they’re absent the brain and body have a difficult time managing pain on their own. This creates an increased sensitivity, as stated before in the muscle pain symptom. This is the primary reason why a substitute for pain management is often prescribed by doctors during fentanyl detox
  • Psychological problems: depression, anxiety, irritability, insomnia, and cravings are the least likely to diminish during phase three of detox. Being that opioid drug addiction is taxing on the psyche, it’s paramount that tools are developed to help users regain their mental health and emotional well-being. This is often done in the form of therapy provided by rehab centers and expert medical supervision.
  • PAWS: post-acute withdrawal syndrome is a phenomenon wildly debated in the healthcare industry. The idea is that, due to the trauma set forth by opioid addiction and the detox process, the brain can remain in a state of shock well after the generalized fentanyl withdrawal timeline. This can mean that the psychological symptoms found throughout the withdrawal stage persist, as well as—although less common—the physical ones

By and large, during phase three is when the physical symptoms come to a halt and the user is capable of operating in a healthier, happier, and clearer manner. This is when cravings will need to be managed and tools will need to be developed to ensure that the patient remains sober and avoids relapse.

How is Fentanyl Withdrawal Measured?

The estimation of withdrawal severity is a critical measurement that is factored into detox strategy. It can be the difference between whether or not a clinician or doctor recommends medically assisted detox. Due to the sheer strength of fentanyl, most experts will advise against detoxing without medical supervision. This is imperative to avoiding relapse (let alone the health complications that may arise).

The way in which this measurement is taken is through COWS.

What is COWS?

COWS is The Clinical Opioid Withdrawal Scale, which is a tool utilized by clinicians to evaluate the severity of a given patient’s withdrawal. It categorizes and reflects upon the following 11 symptoms:

  • Vitals (specifically the pulse)
  • Sweating
  • Restlessness
  • Eye Tearing
  • Achiness
  • GI Distress
  • Tremors
  • Yawning
  • Gooseflesh Skin
  • Irritability
  • Anxiety

Each symptom is then given a numeric score in accordance with how severe they are developing, or how severe the patient explains that they are feeling them. The overall score ranges from 0 to 48, with 48 being the strongest degree of withdrawal severity. This score is usually what’s used to determine whether the patient is going to need tapering, medicine, or the full range of care needed to support the patient through detox.

Is Fentanyl Withdrawal Deadly?

The ironic relationship between fentanyl withdrawal and death is that it’s basically nonexistent. While alcohol and benzodiazepines can kill the user during detox, rarely is it ever the case that, due to the symptoms alone, the withdrawals turn deadly. Typically, the most worrisome symptom of fentanyl withdrawal is dehydration and a relapse-provoked overdose.


Being that fentanyl withdrawal can cause extreme diarrhea and vomiting, if the user is not under the care of medical professionals than their hydration levels can drop to a fatal level. This can destroy organ symptoms, send the body into shock, cause seizures, and heavily impair the healing process that must occur throughout the withdrawal phase.

Relapse Overdose

Fentanyl is hands down the strongest opioid available on the market. In its FDA-approved form, it is 50 times stronger than heroin per microgram, and 100 times stronger than morphine. In its street-produced form—often imported from China or Mexico—it can be double that strength, making it nothing short of a killer.

When those going through detox decided against pushing through the process, they will often run immediately back towards fentanyl to alleviate the symptoms. Unfortunately, tolerance can drop significantly in only a matter of days. This means that while the person could “handle” a certain dosage of fentanyl before they attempted detox, when they take that same amount afterwards it can cause them to overdose.

Why It’s Imperative to Medically Detox from Fentanyl

If being addicted to heroin or Percocet is scary, then addiction to fentanyl is nightmarish. In 2016 alone, synthetic opioids (fentanyl, for example) were involved in 50% of opioid-related deaths, killing 19,413 people alone. The number increased in 2017 and 2018. The sad reality is that fentanyl, due to its potency, is easy for drug mules to transport and cut into their preexisting products.

Many deaths at the hand of this opioid happen without the user understanding the substance he or she is ingesting. Thousands of deaths have now occurred because of fentanyl laced drugs in counterfeit prescription medications, cocaine, heroin, and other drugs. When asking the question why it’s imperative that someone detoxes from fentanyl in a controlled environment, with the help of medical professionals, the answer has two parts; to avoid relapse and ensure safety.

Avoiding Relapse

Addiction to fentanyl means that the user puts themselves in a life or death situation daily. Unlike other substances, where a relapse means prolonged use, a relapse with this synthetic opioid can bring immediate death. Due to the nature of opiate withdrawals, it is immensely difficult to stomach the process alone and often leads to a reuse of fentanyl.

Medically-assisted detox or inpatient detox can mitigate these chances by lessening the symptoms, providing support throughout the process, and generally easing the journey. If the detox process is easier, then it’s easier to overcome. And once the hump is crossed, the chance of an immediate relapse decreases.

Remember, a relapse with fentanyl can be fatal.  

Avoiding Health Complications

While opioid withdrawal is unlike other substances in which it is not known to outright kill a patient, there are problems that can ensue. From psychological conditions that manifest during detox, extreme dehydration, to an inconsistent respiratory symptom, clinicians and addiction specialists will monitor a patient’s detox to ensure that nothing goes wrong. If it does, they will know what to do to reverse the reaction.

Get Help Today

There is no fearmongering or dramatization when the topic of fentanyl is addressed; it is absolutely the most dangerous drug to be addicted to. That’s why it’s imperative that if you or someone you know is looking to detox and quit, they not only do so, but do it under the care of professionals.

This is not a situation to remain stagnant about. If you are considering putting an end to personal fentanyl abuse and facing withdrawal, then make the decision, remain steadfast, and reach out to experts to help you through. With the resources available and the studies done on opioids, there is no reason you won’t be able to win this fight and lead a healthier, happier life.


Darke, Shane. “Yes, People Can Die From Opiate Withdrawal.” UNSW Sydney. 15 Mar. 2019. https://ndarc.med.unsw.edu.au/blog/yes-people-can-die-opiate-withdrawal

Fudin, Geoffrey. “Opioid Withdrawal: A New Look at Medication Options.” Practical Pain Management. 15 Mar. 2019. https://www.practicalpainmanagement.com/treatments/pharmacological/opioids/opioid-withdrawal-new-look-medication-options

“Fentanyl Addiction, Abuse and Treatment.” Addiction Center. 15 Mar. 2019. https://www.addictioncenter.com/opiates/fentanyl/

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