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How Does Fentanyl Kill You? What Is a Lethal Dose?

How does fentanyl kill you? Learn how to recognize the signs of fentanyl addiction and overdose here.

How Does Fentanyl Kill You

Article Contents

What Is Fentanyl?

Fentanyl is an extremely powerful synthetic opioid that is fifty times stronger than heroin and one hundred times stronger than morphine, making fentanyl one of the most dangerous opioids. Even a standard dose of fentanyl can be potent enough to inflict an overdose.1

Doctors may prescribe fentanyl for pain management when other pain medications are ineffective. However, it is only prescribed to people at least eighteen years old and in extreme cases of pain due to its high risk of addiction and potential for overdose. When prepared as a prescription, fentanyl is available as a shot, tablet, or long-lasting patch.

What Is a Lethal Dose of Fentanyl?

The chance of ingesting a lethal dose of fentanyl increases when the product is illegally obtained because the exact makeup of the drug is usually unknown. Illegal fentanyl is most frequently distributed as a powder, on blotter paper, or in pill form so that it can be disguised as other medications. Fentanyl powder is particularly dangerous as it is frequently cut with other drugs, such as cocaine, heroin, or meth.

Fentanyl has no smell, flavor, or color, so it is virtually impossible to detect without test strips. Hence, fentanyl overdoses are a common occurrence. In 2017, 59% of all opioid-related deaths were caused by fentanyl.2

What Are the Signs and Symptoms of Fentanyl Addiction?

One of the dangers of fentanyl is its high addiction potential. Some of the most common symptoms of fentanyl addiction include:

  • Social withdrawal
  • Constricted pupils
  • Decline in cognitive function
  • Difficulty paying attention
  • Inability to quit or cut down on the drug use
  • Impaired judgment
  • Changes in sleep patterns, such as drowsiness or insomnia
  • Withdrawal symptoms when drug use stops
  • Difficulty concentrating and completing tasks
  • Mood swings and irritability
  • Lack of motivation 
  • Forging prescriptions for fentanyl or visiting multiple doctors to try to obtain prescriptions

Effects of Fentanyl on the Body

Fentanyl creates feelings of euphoria, relaxation, and drowsiness, which are the common reasons why it is abused. In addition, the drug is misused as a sleep aid for its sedative and relaxing effects.

It is important to note that some medications can worsen the side effects of fentanyl when taken simultaneously. Some combinations, such as fentanyl and codeine, can increase the potencies of both drugs, leading to severe side effects and potentially a fatal fentanyl overdose.

Common Side Effects

Some of the most common side effects that fentanyl has on the body include:
  • Drowsiness, fatigue, and lethargy
  • Nausea and vomiting
  • Confusion
  • Constipation
  • Sedation, lack of responsiveness
  • Unconsciousness
  • Extreme euphoria
  • Difficulty breathing

Impact of Fentanyl Use and Side Effects

These side effects can quickly become dangerous because they directly impact the body’s central nervous system. Enough fentanyl can cause the respiratory system to stop working properly, causing the person to stop breathing.

Because of the severe risks fentanyl can cause, it is essential to learn about fentanyl overdose symptoms.

What Are the Signs of Fentanyl Overdose?

Fentanyl overdose symptoms occur when a person takes a fentanyl dosage higher than their body can handle. While the fentanyl overdose limit varies from person to person, it does not take much for fentanyl to be lethal.
In fact, it is impossible to know how much or little it will take for a person to overdose on the drug. It is estimated that over 150 people die every day from synthetic opioid overdoses.3

Indications of a Fentanyl Overdose

A normal dose of fentanyl is enough to cause an overdose in some people. These are the most common signs of fentanyl overdose to watch for:
  • Unresponsiveness or unawareness
  • Pinpoint pupils
  • Blue lips and fingernails
  • Low heart rate 
  • Body goes limp
  • Vomiting
  • Difficulty speaking
  • Can’t be awoken from sleep
  • Face/body becomes pale and clammy to the touch
  • Slowed breathing, no breathing, or irregular breathing

If you suspect someone is experiencing symptoms of a fentanyl overdose, call 911 immediately.

What Are the Withdrawal Symptoms of Fentanyl?

Fentanyl is highly addictive. Prolonged fentanyl misuse can cause the body to become dependent on the drug to function, resulting in withdrawal once fentanyl use stops. Withdrawal symptoms can begin twenty-four to thirty-six hours after the last dose and last anywhere from four to twenty days, depending on the severity of the addiction.

Common Withdrawal Symptoms

The most common withdrawal symptoms include:

  • Bone pain
  • Sweating and fever
  • Uncontrollable leg movements
  • Dilated pupils
  • Nausea and vomiting
  • Muscle cramping
  • Diarrhea
  • Cold flashes with goosebumps
  • Shaking or tremors
  • Intense fentanyl cravings
  • Irritability and anxiety

Treatment Options for Fentanyl Overdose

How does fentanyl kill you

Several steps are available in the fentanyl overdose treatment plan. These will be detailed below.


Typically, as with any other illicit substance, treatment will begin with medical detoxification. Patients are usually given methadone to help them wean off fentanyl safely and with fewer withdrawal symptoms.


Once patients complete detoxification, the next step is therapy. Cognitive behavioral therapy (CBT) is the most common form of psychotherapy for those recovering from substance abuse. Nonetheless, other evidence-based therapies are available, such as dialectical behavior therapy (DBT) and motivational interviewing.

Outpatient Programs

Outpatient programs offer treatments without requiring patients to live at the recovery facility. This option is ideal for those with less severe cases and can maintain a healthy routine and environment outside the facility.

Inpatient Programs

Inpatient treatment programs are usually for cases requiring intensive care, as they require the patients to live at the facility throughout the duration of their treatment.

Aftercare Programs

Recovery doesn’t end after a patient has gone through detox and rehab, as they will still require support from friends, family, and their treatment team. The goal of recovery is to help people improve their lives by living and maintaining a healthy, positive, and substance-free lifestyle.

There has been a 5% increase in all opioid-related drug overdoses since 2018. Thus, prevention and treatment programs are vital in reducing drug use, overdose, and deaths.4

Get Help for Fentanyl Overdose at Iris Healing®

If you or a loved one are struggling with fentanyl addiction, contact us at Iris Healing® today to learn about our treatment options. We are here to help you recover and take charge of your life.

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