Why is Fentanyl So Dangerous?: Learn the Overdose Risk

Fentanyl is a synthetic opioid 50-100 times stronger than morphine, which is why fentanyl is so dangerous. It has powerful opioid properties and is therefore overused or misused. When fentanyl is added to heroin and/or other drugs, its potency increases, increasing its overdose potential.1

What is Fentanyl and How is it Used?

Fentanyl is a potent synthetic opioid drug. It is approved by the Food and Drug Administration for use as an analgesic (pain relief) and anesthetic. 1

It is classified as a Schedule II narcotic under the United States Controlled Substances Act of 1970. 1

Fentanyl was developed specifically for pain management treatment in cancer patients. It can be prescribed to treat extreme pain for your post-surgical pain or if you have advanced-stage cancer.2

In What Forms is Fentanyl Taken?

Fentanyl pharmaceutical products can be taken in the following forms:1

  • Injection formulas
  • Sublingual tablets (Abstral)
  • Sublingual sprays (Subsys)
  • Nasal sprays (Lazanda)
  • Effervescent buccal tablets (Fentora)
  • Transdermal patches (Duragesic)
  • Oral transmucosal lozenges commonly referred to as “lollipops” (Actiq)

Fentanyl is relatively tasteless, regardless of its form.1,2 It is hard to detect, but fentanyl test strips can be used to detect its presence in other substances.1,2 They may not always be 100% accurate, though.1,2

Why Are Drugs Cut with Fentanyl?

Since fentanyl has strong opioid properties, it is misused and overused. Unfortunately, fentanyl is produced clandestinely in Mexico.2

If this fentanyl is purchased and used, there is very little quality control which increases its overdose potential.2

Illicitly produced fentanyl is sold alone or combined with pharmaceutical drugs such as oxycodone. Dealers may also cut their drugs like heroin, Xanax, or prescription painkillers with fentanyl to make more money and increase potency. This can be deadly, especially for people who don’t realize they’re taking fentanyl.

Illegal fentanyl is being mixed with other drugs, such as:2,3

  • Heroin
  • Cocaine
  • Methamphetamine
  • 3,4-methylenedioxymethamphetamine (MDMA)
  • Xanax

Fentanyl patches can be misused by removing their gel contents and then injecting the contents. Patches have a history of being frozen, cut into pieces, and then placed in the cheek cavity or under the tongue. Fentanyl has been produced illicitly and has been identified in counterfeit pills that can mimic FDA-approved pharmaceutical drugs like oxycodone.2

Because fentanyl can be taken in a variety of forms, it is oven cut in with other substances to induce severe highs, such as being spiked into blotter paper.2

What Are Fentanyl’s Street Names?

Fentanyl has many forms and street names. Its street names are as follows:1,2

  • Apace
  • Poison
  • China White
  • China Town
  • China Girl
  • Goodfellas
  • Dance Fever
  • Great Bear
  • He-Man
  • Tango & Cash

Fentanyl Side Effects

Fentanyl produces effects on the brain and creates bodily side effects.

Its mechanism of action is like that of other opioid drugs. Fentanyl molecules target opioid receptors in the body, most of which are in the brain. They can be found within specialized neuroanatomical structures that control emotions and pain.4

Fentanyl’s biochemical properties allow it to bind to the brain’s mu receptors because it is a mu-selective opioid agonist.4

It also can activate and impact other opioid system receptors like the delta receptors. Research is now showing it may also affect the kappa receptors as well.4

When these receptors are activated by fentanyl, it produces the side effect and feeling of analgesia.4

Furthermore, the neurotransmitter dopamine is increased in the brain, which leads to feelings of relaxation and exhilaration (excitement). 4

Some additional side effects include: 4

  • Pain relief
  • Euphoria
  • Sedation
  • Confusion
  • Drowsiness
  • Dizziness
  • Nausea and vomiting
  • Urinary retention
  • Pupillary constriction
  • Respiratory depression

What Are Fentanyl’s Bodily Effects?

Fentanyl is metabolized by the liver by the CYP450 enzyme. To be more specific, it is metabolized hepatically by the CYP3A4 enzyme and has a half-life of 3 to 7 hours.4

It is primarily excreted both in the urine and feces, with 75% excretion happening through urination and 9% in the feces.4

Fentanyl severe side effects include:1,2,4

  • Overdose
  • Stupor
  • Cyanosis
  • Coma
  • Cold and clammy skin
  • Changes in pupillary size
  • Respiratory failure leading to death

Risks of Fentanyl Use

Since Fentanyl is significantly stronger than morphine, a dose of only 100 micrograms can produce equivalent analgesic effects to about 10 mg of morphine. 1,2,4

Per The National Institute on Drug Abuse, the U.S. government does not track death rates for every drug. Yet, the National Center for Health Statistics (NCHS) at the Centers for Disease Control and Prevention collects information on deaths that involve the most used drugs available through 2020.6

These figures can be found on a searchable database called CDC Wonder.6

Per these statistics, there were 91,799 drug overdose deaths reported in 2020. This is an increase from the amount reported in 2019.6

Deaths involving synthetic opioids, primarily fentanyl and other than methadone, also rose. There were 516 overdose deaths reported in 2020 for this category.6

Why is Fentanyl so Deadly?

Fentanyl is deadly due to its severe potency. It affects systems such as the pulmonary system and brain function, causing breathing to slow or stop altogether.4,6

What Are Fentanyl’s Effects on the Pulmonary System?

The effects of fentanyl on the respiratory system include direct inhibition of respiratory neural activity. It also decreases the peripheral and central chemoreceptor gains on ventilation.6

In other words, fentanyl lowers the responsiveness to the stimulatory effects of carbon dioxide on the human body, negatively impacting your breathing.6

When taking fentanyl in high doses, it can create chest wall glottic rigidity, making it very difficult for medical professionals to ventilate you if needed. This is quite a complication to face for medical providers that would impact if and how they can treat your system.6

How Does Fentanyl Impact Brain Function?

Fentanyl works by binding to the body’s opioid receptors. These are found in areas of the brain in charge of controlling pain and emotions.4

Since fentanyl is an analgesic and opioid, it is a central nervous system (CNS) suppressant. As a result, when it is misused and/or overused, you run the risk of experiencing:1,2,4

  • Respiratory depression
  • Respiratory arrest
  • Unconsciousness
  • Coma
  • Death

These symptoms are on the severe side and typically occur during an overdose.4

Also, the presence of a triad of symptoms such as pinpoint pupils, coma, and respiratory depression are strongly suggestive of opioid poisoning. If this occurs, please contact a medical provider immediately or contact emergency medical services (EMS).4

Milder symptoms would be happiness, nausea, sedation, tolerance, and drowsiness because of it binding to the brain’s pain and emotion receptors.1,2,4

There are more potent synthetics than fentanyl, such as carfentanil. Fentanyl test strips can be useful, but they are not 100% accurate 100% of the time. Therefore, they might not detect the drug’s presence or the right amount of it.7,8

Fentanyl Potency: Overdose Risk and Signs

Fentanyl comes in a variety of forms. As such, you may use it in multiple forms, at high doses.8

Because drugs are often cut with fentanyl, unbeknownst to the user, they may use a drug believing it to be MDMA or heroin and end up overdosing on fentanyl.

The fact that it is tasteless can also cause no deterrence towards taking more of it than intended. For example, there is no taste aversion happening for you, so you continue to take in more.8

Fentanyl potency (especially if a transdermal patch is cut open and its contents are either injected or placed in your mouth under the check) is very high and can reach your CNS, pulmonary, and other bodily systems rapidly.4,8

All of these reasons can lead to the following major signs and symptoms of overdose:1,2,4,8

  • Pinpoint pupils
  • Coma
  • Respiratory depression

Fentanyl Withdrawal, Dependence, and Addiction

Experiencing an overdose of fentanyl can speed up your path toward dependence and opioid addiction. This is because of fentanyl potency and because often, illicit fentanyl is cut in with other substances.8

The high fentanyl potency greatly increases the risk of overdose, especially if you use a substance without being aware of what is in the substance. You can potentially underestimate the dose of opioids you are taking, therefore increasing tolerance, and you’re inadvertently taking more than you intended.8

Naloxone is a medicine that can be given to you to reverse a fentanyl overdose. Multiple naloxone doses might be necessary because of fentanyl potency.8

If you have overdosed and emergency medical providers utilize medication such as Narcan or naloxone to revive you, it may give you a false sense of security. For example, cognitively, your thoughts may tell you it is ok to overdose since paramedics or other bystanders may be able to quickly revive you with Narcan.8

Some withdrawal symptoms of fentanyl are also unpleasant. If you go to a medically managed detox, credentialed professionals can give you prescription medications to lower the effects. However, experiencing uncomfortable withdrawal symptoms may excel your dependence since you may want to use more fentanyl to feel ‘comfortable again.’ 8

Fentanyl withdrawal symptoms include:8

  • Anxiety
  • Dizziness
  • Nausea
  • Fever
  • Vomiting
  • Runny nose
  • Irritability
  • Sleepiness
  • Muscle or joint aches
  • Dilated pupils
  • Heavy sweating
  • Trouble sleeping
  • Goosebumps and chills
  • Abdominal cramps
  • Increased breathing rate

If you or a loved one feel the treatment is the right fit or you’re unsure of where to start, contact a treatment specialist at 800-914-7089 (Info iconWho Answers?) .


  1. Department of Justice/Drug Enforcement Administration Drug Fact Sheet. (2020, April). Fentanyl.
  2. United States Drug Enforcement Administration. (n.d.). Fentanyl.
  3. National Institute on Drug Abuse (NIDA). (2017, September). What is MDMA?
  4. Ramos-Matos, C.F., Bistas, K.G., & Lopez-Ojeda, W. (2022). StatPearls. Fentanyl.
  5. National Institute on Drug Abuse (NIDA). (2022, Jan 20). Overdose Death Rates.
  6. Kiyatkin E. A. (2019). Respiratory Depression and Brain Hypoxia Induced by Opioid Drugs: Morphine, Oxycodone, Heroin, and FentanylNeuropharmacology, 151, 219–226.
  7. Drug Enforcement Administration. (n.d.) Carfentanil: A Dangerous New Factor in the U.S. Opioid Crisis.
  8. National Institute on Drug Abuse (NIDA). (2021, June). Fentanyl Drug Facts.
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