Fentanyl Side Effects and Withdrawal Symptoms

Fentanyl is an extremely potent opioid that can cause dangerous side effects, including slowed breathing, sedation, confusion, and overdose. When use stops, withdrawal symptoms can include intense cravings, anxiety, muscle aches, nausea, sweating, insomnia, and flu-like discomfort. Because fentanyl carries a high risk of overdose and dependence, professional medical support is often recommended for safe withdrawal and recovery.

Fentanyl is not like other drugs. It does not give you much room for error. One wrong pill, one dose slightly heavier than the last, and you may not wake up. That is not an exaggeration. It is how this drug works, and it is why so many men in Arizona and across the Southwest are losing their lives to it right now.

If you or someone you care about is using fentanyl, or you suspect they might be, this article covers what fentanyl is, what it does to the body, what withdrawal looks like, and the next steps to take for recovery.

What Is Fentanyl?

Fentanyl is a synthetic opioid, meaning it is manufactured in a lab, not derived from a plant. Medically, it is used to treat severe pain, typically in surgical or cancer care settings, and is administered under close clinical supervision.

The fentanyl driving the overdose crisis is different. It is illicitly manufactured fentanyl (IMF), produced in clandestine labs and pressed into counterfeit pills designed to look exactly like legitimate prescriptions such as Xanax, Percocet, Adderall, and oxycodone. It is also cut into heroin, cocaine, and meth, often without the user’s knowledge.

What makes it so lethal: fentanyl is approximately 100 times more potent than morphine. A lethal dose is measured in micrograms, an amount invisible to the naked eye. There is no safe way to eyeball a dose [1].

Is Fentanyl in Arizona?

Fentanyl now accounts for 60% of all drug-related overdose deaths in Arizona. In Maricopa County alone, more than three people die from fentanyl every day [2].

Since 2015, fentanyl deaths in the state have increased by nearly 4,900%. And while overdose deaths nationally declined slightly from 2023 to 2024, Arizona is moving in the opposite direction, with overdose deaths trending back up in 2025, hitting monthly records not seen in years [3].

The men most affected are between 18 and 44. Many are working. Many are not people who identify as “addicts.” They were managing pain or stress, or they took what they thought was a different drug entirely.

Side Effects of Fentanyl Use

Even in the short term, fentanyl puts serious strain on the body and brain. Common side effects include:

• Slowed or shallow breathing

• Extreme drowsiness or sedation

• Confusion or impaired judgment

• Nausea and vomiting

• Constipation

• Dizziness and loss of coordination

• Pinpoint pupils

• Low heart rate and blood pressure

With repeated use, the brain’s natural opioid receptors are suppressed. The body stops producing its own dopamine and endorphins at normal levels. Tolerance builds fast; what once produced a high now barely keeps withdrawal at bay. This is the trap fentanyl sets, and it sets in quickly.

Signs of a Fentanyl Overdose

A fentanyl overdose can happen the first time someone uses it, and it can happen to someone who has been using it for years. It can happen when a person relapses after a period of sobriety because their tolerance has dropped. Know these signs [4]:

• Loss of consciousness

• Slow or shallow breathing

• Choking or gurgling sounds

• Limp body

• Blue or grayish lips, fingertips, or skin

• Pale or clammy skin

If you see these signs, call 911 immediately. If naloxone (Narcan) is available, administer it. Arizona has Good Samaritan laws that provide legal protection when you call for help during an overdose.

What Does Fentanyl Withdrawal Feel Like?

Withdrawal is the body’s response to the sudden absence of a drug it has come to depend on. With fentanyl, withdrawal is intense, physically painful, and psychologically brutal and is for many users the primary reason they keep using even when they want to stop.

Symptoms typically begin within 8 to 24 hours of the last dose and can include:

• Early phase (first 24–48 hours): Intense drug cravings, anxiety and agitation, muscle aches, restlessness, sweating, chills, runny nose/watery eyes, insomnia

• Peak phase (days 2–4): Severe muscle cramping and bone pain, nausea, vomiting, and diarrhea, rapid heart rate and elevated blood pressure, extreme irritability and mood swings, depression and dysphoria

• Post-acute phase (weeks to months): Persistent low mood, difficulty sleeping, diminished ability to feel pleasure (anhedonia), cravings that can resurface without warning

Fentanyl withdrawal is rarely fatal on its own, but the combination of dehydration, cardiovascular stress, and the near-certain relapse risk makes unsupervised detox dangerous. Most men who try to quit cold turkey alone don’t make it through the acute phase, and when they relapse, their tolerance is lower, and the risk of overdose is higher than before.

Fentanyl Detox and Rehab in Arizona for Men

Withdrawal is not treatment. Detox gets fentanyl out of your system. Treatment addresses why it was there in the first place. At AnchorPoint Recovery, a rehab center for men, we work with men who have been using fentanyl, sometimes for years, sometimes without fully realizing what they were taking.

Many of them came in carrying more than addiction, such as trauma, loss, grief, a lack of purpose, and co-occurring mental health challenges like anxiety and PTSD. Our treatment model brings together evidence-based clinical care, including EMDR, CBT, IFS, and polyvagal-informed therapy, and a faith-anchored framework that meets men where they are.

If you or someone close to you is using fentanyl, or you’re not sure what they’re using but something is wrong, call us now. Our team can talk you through what you’re seeing, what options are available, and what the next steps look like for your situation.

Sources 

[1]  Maricopa County, et al. (2025). Focus on fentanyl. Maricopa County Department of Public Health. 

[2] Arizona Capitol Times, et al. (2026, February 18). Fentanyl overdose deaths on the rise again in Arizona. Arizona Capitol Times.

[3] Drug Enforcement Administration, et al. (2025). Facts about fentanyl. U.S. Drug Enforcement Administration

[4] National Institute on Drug Abuse, et al. (2025). Fentanyl drug facts. National Institute on Drug Abuse.

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