ISO Drug: Stronger Than Fentanyl

Clinical Reviewer

The relative scarcity of fentanyl on the illicit drug market, caused by China banning its production in August of 2019, has caused a new deadly drug to emerge Isotonitazine, known as ISO.

  In This Article

What is ISO drug?

ISO is a derivative of etonitazene, a synthetic opioid first developed by pharmaceutical companies in the 1950s to treat pain. It is rarely used in the medical community because there are safer options.  ISO is highly potent and comes with dangerous side effects.

How dangerous is ISO drug?

ISO is believed to be more potent than fentanyl. People are at least 10x more likely to overdose on ISO than overdose on methadone, which is also an opioid.

A recent article in U.S. News and World Report stated that ISO is causing 40 to 50 overdose deaths per month in the United States (up from about 6 per month in the summer of 2019). It has been detected in the blood of overdose victims in Indiana, Wisconsin and in our backyard in Illinois where, in some cases, it was mixed with cocaine.

The Drug Enforcement Administration (DEA) has now reclassified the potent synthetic opioid as a Schedule 1 drug with a high risk of abuse by users.

ISO is even more concerning to health practitioners because it is not easily detected in routine toxicology tests.

Reported side effects of ISO include:

The potency of the ISO drug can also lead to withdrawals worse than heroin withdrawal symptoms. ISO is also more likely to cause long-lasting withdrawal symptoms, known as opiate PAWS
Adding to the danger, ISO is usually injected which can lead to life-threatening complications like heroin abscesses.

What does ISO look like?

ISO comes in the form of crystals or a white, off-white, or yellow powder that can be mixed with other substances (e.g., heroin, cocaine) or pressed into tablets.
Photos of Confiscated ISO In Various Forms
Confiscated ISO drug - pills, powder, crystal

How do you stop ISO addiction?

Because ISO is an opioid, the same treatments that are effective for heroin or fentanyl addiction are the ideal choice for opioid addiction. 

The FDA-approved medications for opioid addiction are Suboxone, methadone and Vivitrol. Symetria offers all these and other medications with promising research. Though, the most common is Suboxone.

(See also the methadone vs. Suboxone article)

Suboxone in Illinois

Get quick access to Suboxone (Buprenorphine) anywhere across Chicago.

Suboxone in Texas

Get fast access to Suboxone or related addiction or mental health medications in the Houston or Fort Worth areas. 

Suboxone Fort Worth Area

Suboxone Houston Area

For more general education on treatment options, check out What is a Suboxone Clinic? and What is an IOP program?

"Isotonitazene-related overdose deaths are on the rise both nationally, and even more so locally. Symetria has a large presence in Illinois, which is a state seeing one of the highest rates of ISO-related fatalities. This drug is the latest potent synthetic opioid to be manufactured and is giving rise to the same difficulties as Fentanyl. It is very lethal, being cut into a variety of other drugs unknowingly, not picked up on drug screens and easily obtained on the dark web. These qualities are a recipe for fueling another surge in the opioid epidemic. Treatment professionals on the front lines of this battle need to be aware of the possibility that ISO is now available and being used by their patients."

Symetria doctors follow rigorous sourcing guidelines and cite only trustworthy sources of information, including peer-reviewed journals, count records, academic organizations, highly regarded nonprofit organizations, government reports and their own expertise with decades in the field.

Blanckaert, P., Cannaert, A., Van Uytfanghe, K., Hulpia, F., Deconinck, E., Van Calenbergh, S., & Stove, C. (2020). Report on a novel emerging class of highly potent benzimidazole NPS opioids: Chemical and in vitro functional characterization of isotonitazene. Drug Testing and Analysis12(4), 422–430.

All content is for informational purposes only. No material on this site, whether from our doctors or the community, is a substitute for seeking personalized professional medical advice, diagnosis or treatment. Never disregard advice from a qualified healthcare professional or delay seeking advice because of something you read on this website.

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  • Making a product that kills you seems like a rather dumb way to sell something. Wouldn’t they go out of business quick and be left holding the bag?!!

    1. Opiate users look for the stuff that kills people because it’s more potent. Plus, it doesn’t show up on drug screen.

    1. Yes. Isotonitazene can be tested separately. It would not come up as an opioid on urine drug screening.

  • My brother died March 11th of this year after using cocaine that I’m now pretty sure was laced with either ISO or tranq.

    1. I’m so sorry to hear about the loss of your brother. This epidemic is taking far too many lives. It’s truly heartbreaking.

    1. Yes. Iso (Isotonitazene), or any other unregulated non-sterile substances, can cause infections when injected into the body.

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    Do you live in Illinois or Texas?

    Symetria has addiction treatment clinics across the state. You can likely get scheduled TODAY — medications or therapy.

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