The opioid crisis continues to evolve, with new synthetic opioids showing up in the illegal drug market. These drugs are far more powerful and deadly than many people realize. Two of the most concerning are also two of the least talked about: carfentanil and nitazenes. Both of these substances are driving a new wave of overdoses, due to their unknown presence in street drugs and pressed pills [1].
At Clear Behavioral Health, we value education, raising awareness, and increasing understanding surrounding the drug landscape, so you and your loved ones know the risks and where to turn for help.
What are examples of synthetic opioids?
Synthetic opioids are drugs that are lab-made rather than natural opium derivatives, like other opiates. Some are prescribed in medical settings, while others are created illegally.
Commonly prescribed synthetic opioids include:
- Fentanyl – prescribed for severe pain, especially cancer treatment.
- Methadone – often used in opioid treatment programs to aid in opioid cessation.
- Tramadol – prescribed for moderate pain relief.
While these medications can be used safely under medical supervision, the illegally manufactured versions pose a danger. These include fentanyl produced in illegal labs, as well as newer and less widely understood substances like carfentanyl (carfentanil) and nitazenes [6].
Related: Understanding and Overcoming Prescription Drug Addiction
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The rise of carfentanil and nitazenes
Unlike fentanyl, which has almost become a buzzword in conversations about overdose, carfentanil and nitazenes are often left out of the conversation. Yet, they are quietly wreaking havoc in communities across the country.
These substances are rarely sought out directly. Instead, they are laced into counterfeit prescription pills, heroin, cocaine, methamphetamine, MDMA, and even drugs marketed as fentanyl itself. The result is people often have no idea they are consuming one of the deadliest synthetic opioids in circulation [2,3].
What is carfentanil?
Carfentanil is an extremely potent opioid originally developed for veterinary use in sedating large animals such as elephants. It is estimated to be about 100 times stronger than fentanyl and up to 10,000 times stronger than morphine [3].
Carfentanil vs fentanyl
While fentanyl itself is already a leading cause of overdose and deaths, carfentanil is vastly more lethal. Even an amount smaller than a grain of salt can cause an overdose in minutes. Unlike fentanyl, which is sometimes prescribed for severe pain, carfentanil has no approved medical use in humans [1,4].
The DEA has described carfentanil as a “synthetic opioid unlike any other,” explaining its extreme risk of death and the tiny margin between a fatal and nonfatal dose [3]. In September 2025, the DEA seized thousands of counterfeit “M30” oxycodone pills containing carfentanil in Western Washington state, highlighting the risks for people who may think they are taking legitimate pain medication [2].
Related: Fentanyl Withdrawal Symptoms & Fentanyl Detox
What is nitazene?
Nitazenes are a class of synthetic opioids known as benzimidazole opioids. They were originally developed in the 1950s, but they were never approved for medical use due to their potency and risk of dependence. In recent years, they have re-emerged in the illicit drug supply [6,8].
Some of the most common forms include:
- Isotonitazene (sometimes referred to as the “ISO drug”) is 500-900 times more potent than morphine.
- Protonitazene – 2,000-2,500 times more potent than morphine.
- Metonitazene – less potent than fentanyl but significantly more potent than morphine
- Etonitazene – produces heart dysfunctions/arrhythmias through cardiotoxicity in preclinical studies
A CDC report documented nitazene-related overdose deaths in Tennessee and highlighted their growing presence across the U.S. [5]. Peer-reviewed research also shows nitazenes can be hundreds to thousands of times more potent than morphine, posing an immense public health challenge [8].
How do carfentanil and nitazenes end up in illegal drugs?
Carfentanil and nitazenes can be bought on the black market, and drug traffickers use them as cutting agents in the drugs they’re selling because of their extreme potency. One of the most alarming aspects is that people usually aren’t seeking out these drugs. Instead, they show up as hidden additives in other drugs, such as:
- Counterfeit oxycodone pills (often called “perks” or “M30s”)
- Fake Xanax bars
- Heroin
- Cocaine
- Methamphetamine
- MDMA (molly)
- Illicit fentanyl
This means someone thinking they’re taking a prescription pain pill or a stimulant could be unknowingly consuming a lethal opioid. The result is a staggering rise in drug overdoses and deaths across the U.S. [1,3].
Why awareness matters
Carfentanil and nitazenes highlight the increasingly dangerous state of the opioid crisis. These synthetic opioids are not only deadly but also deceptive. People who would never intentionally use these lethal substances are becoming victims of the illegal drug trade.
How potency leads to more drug overdose deaths
Another danger about nitazenes and carfentanil is that overdoses are harder to reverse. A typical amount of Narcan that would be used for a fentanyl overdose might not be effective for a carfentanil or nitazene overdose due to their potency.
As a result, multiple doses of Narcan may be required to effectively reverse an overdose [9,10]. Without this knowledge or the appropriate Narcan dose, an opioid overdose can become fatal.
Related: Overdose Awareness: Signs, Symptoms, and How to Get Help
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Getting help at Clear Behavioral Health
If you or someone you love is struggling with substance use, know that help is available. At Clear Behavioral Health, we offer accessible opioid addiction treatment throughout the Los Angeles, CA area, including opioid detox in Gardena and Redondo Beach. We provide compassionate, evidence-based treatment to help you safely detox, address the root causes of addiction, and build a healthier future.
You don’t have to face this crisis alone. Recovery is possible, and treatment saves lives.
References
- Conversion. (n.d.). php/alerts/dhan377 ~ Division of Public Health – Delaware Health and Social Services – State of Delaware. Division of Public Health. https://dhss.delaware.gov/dph/php/alerts/dhan377/
- Centers for Disease Control and Prevention. (2024, October 10). Detection of illicitly manufactured fentanyls and carfentanil in overdose deaths — United States, 2019–2023. Morbidity and Mortality Weekly Report, 73(48). https://www.cdc.gov/mmwr/volumes/73/wr/mm7348a2.htm
- Drug Enforcement Administration. (2025, September 24). Warning: Thousands of counterfeit M30 pills containing carfentanil seized in Western Washington. https://www.dea.gov/press-releases/2025/09/24/warning-thousands-counterfeit-m30-pills-containing-carfentanil-seized
- Drug Enforcement Administration. (2025, May 14). Carfentanil: A synthetic opioid unlike any other. https://www.dea.gov/stories/2025/2025-05/2025-05-14/carfentanil-synthetic-opioid-unlike-any-other
- World Health Organization. (2017, December 13). WHO recommends the most stringent level of international control for synthetic opioid carfentanil. https://www.who.int/news/item/13-12-2017-who-recommends-the-most-stringent-level-of-international-control-for-synthetic-opioid-carfentanil
- Centers for Disease Control and Prevention. (2022, September 16). Notes from the field: Nitazene-related deaths — Tennessee, 2019–2021. Morbidity and Mortality Weekly Report, 71(37). https://www.cdc.gov/mmwr/volumes/71/wr/mm7137a5.htm
- Rasmussen, S. E., et al. (2023). Old drugs and new challenges: A narrative review of nitazenes. Pharmacology & Therapeutics, 248, 108446. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10361140/
- Smith, L., et al. (2023). Nitazenes—heralding a second wave for drug-related deaths in the UK. British Journal of Addiction Studies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7617954/
- Pereira, J. R. P., Quintas, A., & Neng, N. R. (2025). Nitazenes: The emergence of a potent synthetic opioid threat. Molecules, 30(19), 3890. https://doi.org/10.3390/molecules30193890
- Ryan. (2024, May 16). What are Nitazenes? Everything You Need to Know – APCBham. APCBham. https://apcbham.org/what-are-nitazenes-everything-you-need-to-know/