Nitazenes: The New Wave of Synthetic Opioids Taking Hold of the World

Nitazenes were first developed in the 1950s as experimental painkillers but were never approved for medical use. Today, illicit manufacturers—primarily in China, with some smaller Eastern European sites handling packaging—are supplying them to global markets. With Afghanistan’s poppy ban squeezing heroin availability, traffickers have leaned on synthetics that can be shipped out for distribution with ease due to their extremely high potency which allows them to evade detection. Just as fentanyl once displaced heroin, nitazenes are now appearing in counterfeit pills, heroin, fentanyl powders, and even stimulants, offering traffickers an even cheaper, even more powerful alternative.

Potency: Why They’re So Dangerous

Nitazenes are among the strongest opioids ever encountered in the illicit supply. For comparison:

Heroin: ~2–3 times stronger than morphine. Used in tens of milligrams.
Fentanyl: ~50–100 times stronger than morphine. Active in micrograms (µg). A few grains of salt can be fatal.
Protonitazene: comparable to fentanyl.
Spirochlorphine: ~4× stronger than fentanyl. An invisible dose could be lethal.

For all of the following: A speck the size of a pinhead could kill several people.
Metonitazene: ~500 times stronger than morphine.
Isotonitazene: also ~500 times stronger than morphine, with clusters of overdose deaths already linked to it.
Etonitazene: up to 1,000 times more powerful than morphine, making it one of the most potent opioids known.

Consider the fact that 2mg is a lethal dose of fentanyl for an opioid naive individual, now consider the fact that metonitazene and isotonitazene are 5-10 times stronger, with etonitazene being 10-20 times stronger. That means that a dose of only .1-.2mg of metonitazene or isotonitazene would be lethal, and only .05-.1mg for etonitazene. These are mere fractions of what most commonly found milligram scales can accurately weigh, and even if dosing is done via volumetric measurement, any slight mistake in calculations could turn deadly. These are extremely unforgiving drugs when it comes to even the slightest amount of human error. This is why they were never put to use in medicine in the first place. And, quite honestly, the pharmaceutical companies should have communicated the danger appropriately, and laws should have been put forth back then that restricted access. Then again, a lot of the global control mechanisms we now have in place today didn’t exist yet, so warnings likely wouldn’t have yielded much.
I guess hindsight is 20/20.

In real-world terms, a dose of etonitazene small enough to balance on a pencil tip would be fatal to almost anyone whether opioid naive or not. Even experienced opioid users cannot predict their tolerance against these substances, and uneven cutting in powders or pills creates lethal “hot spots.”

Key Takeaway: At these potencies, there is no safe way to eyeball a dose.

An Arms Race of Analogs

As with fentanyl, nitazenes are spawning endless analogues. Small chemical tweaks create new versions that skirt specific bans, leaving law enforcement and legislation playing catch-up. Ohio has already emergency-scheduled multiple nitazenes, but laws at the federal and global level lag behind the rapid analogue churn.

In July 2025, China officially moved to schedule the entire class of nitazene analogues under national control, using a generic legal definition rather than listing only specific compounds. This marks a major turning point: dozens of analogues—many not previously addressed by law—are now subject to control. Alongside this, China has also regulated key fentanyl precursor chemicals (4-piperidone, 1-BOC-4-piperidone) to make manufacture of powerful synthetics harder.

While this doesn’t immediately eliminate illegal supply, generic bans like this are among the strongest legal tools available for cutting off the source of both nitazenes and any rapidly emerging analogues. It puts pressure upstream—chemical suppliers, labs, shippers—to be much more cautious. For the U.S. and Ohio, this means there is hope that some supplies may decrease or slow, but test strips, overdose reversal, and treatment systems will still need to be ready, since illegal manufacture and trafficking often adapt fast. Enforcement remains a big open question. As in other countries, having laws is one thing; prosecuting, tracking supply chains, and shutting down networks is another.

Overdose Reversal: Current Tools and Gaps

Naloxone (Narcan) is still the frontline defense, but nitazene overdoses often require multiple doses and extended observation. Nalmefene (OPVEE) offers longer-lasting reversal but carries risks of precipitated withdrawal in opioid-dependent people, limiting its frontline use.

Experts argue that what’s needed are short-acting, ultra-potent, mu-opioid receptor–selective antagonists—rescue medicines designed for the realities of modern synthetics. After reversal, patients should be transitioned quickly to buprenorphine or methadone as receptor sites begin to come back online, and patients should be offered treatment continuation through medication for opioid use disorder (MOUD) either by private doctor (an approach known as “Office Based Opioid Treatment”, or OBOT) which is often preferred due to reduced stigma or by means of a traditional clinic.

Test Strips: A Lifesaving Line of Defense

One of the most effective harm-reduction tools available right now is drug-checking with test strips.

Fentanyl test strips are widespread, but they do not detect nitazenes.
Nitazene-specific test strips have recently become available and can help identify these ultra-potent opioids before use.
A trusted source is BunkPolice.com, which offers nitazene strips along with fentanyl and other substance tests. Readers can use the discount code “BLUELIGHT” for 10% off all products, making it easier to equip yourself, your friends, or your community.

Spirochlorphine (R-6890): An Emerging Concern

While nitazenes dominate the conversation, another synthetic opioid—spirochlorphine (R-6890)—has begun to appear in limited cases. It is far less common but carries serious risks:

Effects: Likely to produce severe respiratory depression, sedation, and overdose risk at microgram-level doses

Detection: No widely available test strips exist for spirochlorphine, and it is invisible to most toxicology panels

Legal status: Not specifically scheduled in the U.S., but prosecutable as a Controlled Substance Analogue – What this means in practice is that as long as there is no proof the substance is being manufactured, sold, or possessed with the intent for it to be consumed by a human being, it is totally legal. Extremely questionable of course, but legal nonetheless.

The chance of encountering spirochlorphine is currently low, but its presence highlights how quickly new synthetics can emerge, often undetectable with existing tools. Its existence should emphasize why one should always stay on their toes, and not entirely depend on things like test strips to ensure safety.

Global Picture

Nitazenes are now being detected on multiple continents. While North America is relatively better prepared due to its fentanyl experience, many countries are encountering these drugs for the first time without robust harm-reduction infrastructure. If cartels expand into these emerging markets, the global opioid supply could shift once again, magnifying risks. And, it isn’t beyond the realm of possibility considering the fact that we are already beginning to see methamphetamine appear more and more in Europe with indications that it originated from cartel supply lines. If the cartel notices this untapped market, why wouldn’t they seek to expand into it as rapidly as possible while the opportunity exists? Hopefully, now that some laws are in place to limit the production and supply of nitazenes, the risk of this happening will dwindle. But, at the same time, the risk is always there now that the heroin supply is finally drying up as middlemen begin to run short and prices skyrocket. This has been something on the mind of the European Union Drugs Agency for some time now, and they used North America as a prime example of what they don’t want the continent in which their member states sit to become.

Harm Reduction: Staying Alive in a Microgram World

When opioids are hundreds to thousands of times stronger than morphine, even a dose invisible to the naked eye can mean the difference between life and death. That’s why harm reduction is the most important line of defense right now.

Carry naloxone everywhere. Be ready to give multiple doses if nitazenes are suspected. Train friends and family in how to use it.

Use test strips every time.
* Fentanyl strips are lifesaving but do not detect nitazenes.
* Nitazene-specific strips are now available and can flag these ultra-potent synthetics before use.
* A trusted source is BunkPolice.com, which ships nitazene, fentanyl, and other drug-checking strips. Use the discount code “BLUELIGHT” for 10% off all products. Stocking them for yourself, your community, or your organization can directly prevent deaths.

Remember the practical limitations. No test strips currently exist for spirochlorphine (R-6890) or many other novel analogues. That makes layered safety practices—not using alone, starting low, and avoiding depressant mixes—essential.

Don’t use alone. If you do, use an overdose-prevention hotline, phone app, or supervised setting that can call for help if you become unresponsive.

Start low, go slow. With potency this unpredictable, smaller test doses reduce risk.

Seek treatment if ready. Buprenorphine and methadone cut overdose risk dramatically and can be started the same day in many Ohio counties. If you, or someone you know, is struggling with opioid use: there is a way out. Medication assisted treatment not only cuts overdose risks dramatically, but it will help prevent withdrawal and cravings as well. MOUD can not only physically save your life, but also (when coupled with appropriate support) can help you get back everything that you might have thought was lost forever due to your use. Support for recovery doesn't even have to be entirely abstinent based anymore. More and more harm reduction oriented groups are popping up every day, so even if you are just looking to change your relationship with mood and mind altering substances without fully giving them up, there is support available. Simply head over to the recovery section of the website for more info!

Bottom line: At a time when a pinhead-sized speck can kill, testing drugs with strips is one of the few practical ways to reduce risk before use if you choose to continue using.

The Road Ahead

Nitazenes are not just another chapter of the opioid epidemic—they represent an escalation. Spirochlorphine’s presence on the market shows how quickly other, less understood opioids can end up replacing the older opioids that are out there as their manufacture decreases and law enforcement gets hip to things. Expanding access to test strips, naloxone, and treatment, while investing in the next generation of reversal agents, is the most direct way to save lives while policy and science catch up.

Outside Resources for More Information

EMCDDA – New opioids: distribution and supply
UNODC Early Warning Advisory – R-6890 (Spirochlorphine)
UNODC – Emerging brorphine analogues (2025) - Includes spirochlorphine
Ohio Board of Pharmacy – Nitazenes
Governor of Ohio – Emergency ban of synthetic opioids
CDC – Fentanyl test strips overview (for reference by those unfamiliar with such)
NPS Discovery – Chlorphine Monograph (Base moiety of the aforementioned spirochlorphine)
Bunk Police – Harm Reduction Tools