An influx of a new class of drug, nitazene—also known as a benzimidazole opioid drug—is now contaminating street drugs.

Nitazene is a strong, synthetic opioids, developed 60 years ago as an alternative to morphine, were never commercially released because of their high overdose risk. Nitazenes are often found in street drugs like heroin, MDMA, fentanyl, and counterfeit oxycodone pills. Since 2019, the DEA has received 2,400 reports related to nitazenes. The challenge is that no test strips are available to detect these drugs.

The DEA states that these synthetic opioids can only be properly identified after a lab test, meaning people often don’t realize they’re buying them until it’s too late.

Nitazenes: The once-forgotten and unapproved medicine that has resurfaced as a street drug.

Benzimidazole Opioids Also Know As Nitazenes

Nitazenes are 2-benzyl benzimidazole opioids, synthetic compounds developed in the 1950s as pain medication. They are part of a group of lab-made opioids that have been linked to a number of overdoses in the U.S. and Europe. Primarily found in illegally purchased pills, heroin, and other opioids, nitazines are most often injected but can also be ingested in different ways.

Three individuals have been hospitalized after consuming as little as half a tablet of what is being sold as “Red Bull MDMA.” NSW Health has issued a warning that these orange/red, rectangular tablets, marked with a Red Bull logo and wording, actually contain the potent opioid nitazene, with no MDMA present.

Very potent, nitazenes are drugs that can be over 40 times stronger than fentanyl. The risk of overdose is extreme, especially for those who are opioid naive. Nitazines can be as strong or stronger than fentanyl and may impair breathing more than other opioids.

Unlike fentanyl, nitazenes do not yet show up on drug tests or testing strips, making their detection difficult.

The Challenge of Treating Nitazene Overdoses

Nitazenes are often mixed with fentanyl and other substances. Because they’re not well known, there’s little information on how to reverse overdoses, or on their interaction with other drugs and alcohol, as highlighted by a 2023 study. This poses significant obstacles because drug users don’t typically know they’re taking nitazenes, and first responders and other medical professionals are tasked with treating overdoses without proper knowledge. Although overdoses can be treated with naloxone, patients may require several doses of Naloxone due to the opioid’s potency and the potential severity of intoxication.

Over 66% of participants in a 2023 JAMA Network Open study who overdosed on nitazenes required two or more doses of naloxone.

Nitazenes vs Fentanyl: A Potency Comparison

While nitazenes are known as ISO or ISO drug on the streets, it’s important to note that not all nitazene compounds are the same. Several distinct types of nitazene or metonitazene have been identified in the illicit drug market, each varying significantly in potency:

Butonitazene: Although slightly less potent than fentanyl, it remains significantly more powerful than heroin.

Isotonitazene (ISO): This compound is known to be approximately 20 to 100 times stronger than fentanyl, making it an exceptionally potent synthetic opioid.

ISO drug, also known as Isotonitazene, has emerged as a new psychoactive substance detected in numerous fatalities across Europe since March 2019 and in the United States since August 2019.

Protonitazene: Estimated to be about 4 times more potent than fentanyl.

Metonitazene: This compound demonstrates equipotency to fentanyl, closely aligning in potency levels.

Etonitazene: Noted for its potency, being around 10 times stronger than fentanyl.

These nitazene analogs, sharing a common benzimidazole chemical structure, exhibit varying degrees of potency. Some nitazene compounds are notably more potent than morphine, with potency levels ranging from hundreds to thousands of times stronger.

The Emerging Threat of Synthetic Opiates in the US

The European Drug Monitoring Center warns of the risk that synthetic opiates could make up for a hypothetical shortage of heroin on the world market.

The European Drug Monitoring Center’s warnings about synthetic opiates potentially filling a global heroin shortage also hold implications for the United States. As Afghanistan’s poppy cultivation dramatically decreases due to the Taliban’s ban — from 575,755 acres in 2021 to just 26,687 acres in 2024 — there is a risk that the U.S. could see an increase in the use of synthetic opiates. These substances, such as fentanyl derivatives and nitazenes, are often much stronger and more dangerous than traditional opiates.

Nitazenes, in particular, are a cause for concern. They are reported to be significantly stronger than fentanyl, which is already up to 50 times more potent than heroin. The U.S. is currently grappling with a severe fentanyl crisis, with a sharp rise in overdose deaths linked to its use.

According to provisional CDC data from 2021, U.S. drug overdose deaths reached a record high of nearly 108,000, with over 75% involving synthetic opioids like nitazenes.

How Lethal synthetic opioids are infiltrating the US Drug Supply

Nitazene drug is being produced in illicit labs in China and often enter the US through the mail, where they are then mixed with heroin by organized crime groups, strengthening the drugs being sold on the streets.

These synthetic opioids are quite cheap, and they’re very strong, which means that you only have to ship a small amount that you can then dilute at the destination to make up a lot of doses.

The Drug Enforcement Agency handed out eight indictments to Chinese companies and employees in October 2023 for importing nitazenes, fentanyl, xylazine and other substances into the U.S. after the agency found the companies shipped two types of nitazenes to Georgia and Florida, and over 80 kilograms of synthetic drug compounds across the country.

Nitazene Overdose and Fatalities: Global Statistics and Trends

Tennessee, USA

In Tennessee, a total of 52 nitazene-involved fatal drug overdoses were identified from 2019 to 2021, with 42 deaths in 2021, marking a significant increase from 10 in 2020.

Ohio, USA

Ohio reported a 19% increase in nitazene-related cases in the first quarter of 2022 compared to the previous year.

United Kingdom

More than 100 deaths have been linked to synthetic opioids called nitazenes in the UK since the summer, with 101 deaths reported across the UK, including 76 in England, and at least 49 cases awaiting further testing.

Estonia

Nitazenes have been detected in Estonia since 2019 and have been increasingly identified in post-mortem analyses of drug-related deaths cases since 2022. In 2023, nitazenes were identified in 48% of drug-related deaths in Estonia and 29% in Latvia.

France and Ireland

Nitazenes have been detected in the French department of La Réunion, and outbreaks of non-fatal overdoses have been noted in Ireland.

Scotland

Nitazenes have been linked to nine deaths in the last six months, and the drugs have been detected in supplies of heroin and benzodiazepines this year.

Australia

In Australia, nitazenes have been found in illicit markets, disguised as heroin and other substances like ketamine. Reports from Sydney indicate tablets sold as MDMA (ecstasy) containing a potent opioid, nitazene, with orange or red colors and a red bull logo.

Street Drugs Found to Contain Nitazene Drug

Nitazene drug also contaminated the illicit drug supply and counterfeit pills. Many police and medical examiner labs do not routinely test for nitazenes, making it difficult to capture the full extent of their impact, which likely results in an undercount of related deaths.

Many fatalities involving nitazenes go undetected as most routine post-mortem analyses do not specifically test for these substances.

Once in the U.S., Nitazenes are often mixed with other drugs, heightening their dangers:

1. Heroin: Nitazenes are mixed with heroin to enhance its potency, drastically increasing the risk of overdose.
2. Fentanyl: One of the most potent opioids available, fentanyl is sometimes laced with nitazenes, making an already lethal drug even more dangerous.
3. Counterfeit Pills: Counterfeit pills that mimic legitimate prescription opioids like oxycodone (marked as “M30” or “M box 30”) or Percocet (“Percs”) frequently contain nitazenes, deceiving users into consuming a highly dangerous product.
4. Ecstasy/MDMA: Nitazenes have also been found in drugs like MDMA, typically used for their stimulant and empathogenic effects, posing an unexpected risk to users.

Nitazenes can only be identified through specialized laboratory testing. The lack of detection means that many drug users unknowingly face extreme risks. Symptoms of overdose can arise quickly—if you suspect you’ve ingested a drug containing nitazenes or if you feel unwell, it’s crucial to seek emergency medical assistance immediately.

Why Are Nitazenes So Dangerous?

Nitazenes bind to mu-opioid receptors in the brain and spinal cord, producing effects similar to fentanyl or morphine but at much higher potency levels. This makes them highly addictive and extremely dangerous. A specific example, isotonitazene, is reported to be several times stronger than fentanyl, which itself is already one of the most potent opioids in circulation.

Overdose risks are amplified because nitazenes are often mixed into counterfeit pills or other substances, leaving users unaware of their presence. Toxicology reports frequently identify nitazenes in overdose cases where victims were unaware they had ingested such a potent opioid. The dangers include:

Severe respiratory depression: Even small doses can slow or stop breathing, leading to death.
Difficulty reversing overdoses: Standard doses of naloxone may be insufficient, requiring higher or repeated administrations.
Hidden presence in drugs: Nitazenes are often undetected in counterfeit pills, which are falsely marketed as legitimate medications.

Potential Effects of Nitazene Exposure:

Extreme Sedation: Users might feel unusually sleepy or find it difficult to stay awake, experiencing deep sedation that is more intense than expected from typical opioid use.

Respiratory Depression: This is a critical and dangerous symptom where breathing becomes significantly slowed or labored, potentially leading to hypoxia (lack of oxygen).

Confusion or Disorientation: The strength of nitazenes can cause significant cognitive impairment, leading to confusion, disorientation, or an inability to think clearly.

Nausea and Vomiting: As with many opioids, nausea and vomiting can occur, but might be more intense due to the high potency of nitazenes.

Euphoria: Initially, there might be a strong feeling of euphoria, which is quickly overshadowed by the negative effects.

Pain Relief: An intense level of pain relief beyond what would be expected from usual doses of other opioids might be experienced.

If you suspect that your symptoms might be due to nitazene or drugs laced with nitazenes, it’s essential to treat the situation as a medical emergency. Prompt action could save your life.

Frequently Asked Questions About Nitazenes

What are nitazenes?Nitazenes are synthetic opioids significantly more potent than fentanyl or morphine. They are often found in counterfeit pills, posing a serious risk to users.
Why are nitazenes so dangerous?Their extreme potency increases the risk of overdose. They are frequently mixed into counterfeit drugs, meaning users might unknowingly consume them.
Can naloxone reverse a nitazene overdose?Yes, naloxone can reverse a nitazene overdose, but higher or repeated doses may be necessary due to their strength.