Cychlorphine: A New Synthetic Opioid More Potent Than Fentanyl is Spreading

A novel synthetic opioid called cychlorphine (also known as N-propionitrile chlorphine) has emerged in the illegal drug supply, with forensic laboratories already linking it to more than two dozen fatal overdoses across the United States and Canada. The Center for Forensic Science Research and Education (CFSRE) issued a public alert in January 2026, and new research published July 10, 2026, confirms this substance poses a significant threat to public health.

What Is Cychlorphine?

Cychlorphine belongs to a class of synthetic opioids called benzimidazolones. These compounds are chemically distinct from fentanyl and traditional opioids like heroin or morphine, but they produce similar effects—and similar risks of overdose and death.

According to the CFSRE alert, cychlorphine was identified in 25 blood specimens from fatal overdoses—21 in the United States and 4 in Canada. The majority of cases were submitted from Tennessee, with additional reports from other regions. More recently, researchers detected cychlorphine in wastewater samples from rural Tennessee communities, indicating ongoing active use in these areas.

Why This Matters for Families

Extreme Potency

Experts, including Dr. Alex Krotulski (Director of Toxicology and Chemistry at CFSRE), have described cychlorphine as more dangerous than fentanyl. While specific potency comparisons are still being studied, early data suggests this compound can produce life-threatening respiratory depression at very low doses.

Difficult to Detect

Standard drug testing panels often fail to identify novel synthetic opioids like cychlorphine. This means:

• A person may not know they are consuming this substance
• Emergency medical providers may not immediately recognize the cause of an overdose
• Toxicology reports may come back with unexpected findings

Unpredictable Drug Supply

Cychlorphine has been found in combination with other substances, including fentanyl. The illegal drug supply is increasingly unpredictable, with new synthetic compounds appearing regularly. Users may believe they are purchasing one substance while actually receiving a dangerous mixture.

Clinical Implications

Overdose Recognition

Cychlorphine overdoses present similarly to other opioid overdoses:

• Slow, shallow breathing or no breathing
• Extreme drowsiness or unresponsiveness
• Pinpoint pupils
• Blue or gray lips and fingernails
• Choking or gurgling sounds

However, because cychlorphine is so potent, overdoses may occur more rapidly and require more intensive medical intervention.

Naloxone Considerations

Naloxone (Narcan) should still be administered in suspected cychlorphine overdoses. While the effectiveness of standard naloxone doses against this specific compound is still being studied, naloxone remains the first-line treatment for any suspected opioid overdose.

Important: Because of the extreme potency of novel synthetic opioids:

• Multiple doses of naloxone may be required
• Rescue breathing and CPR are critical while waiting for emergency responders
• Always call 911—medical attention is essential even if naloxone appears to work

What Families Can Do

Carry Naloxone

If you have a loved one who uses drugs, ensure you have naloxone readily available and know how to use it. Many states allow naloxone to be obtained without a prescription at pharmacies.

Recognize the Signs

Learn to recognize opioid overdose symptoms and be prepared to act quickly. Time is critical in overdose situations.

Use Drug Checking Services

Where available, drug checking services can help identify the presence of dangerous adulterants. While not universally available, these services are expanding in many communities.

Never Use Alone

Encourage your loved one to never use drugs alone. Having someone present who can call for help and administer naloxone can mean the difference between life and death.

Seek Treatment

If your loved one is struggling with substance use, help them connect with treatment resources. Medication-assisted treatment (MAT) for opioid use disorder—including buprenorphine, methadone, and naltrexone—remains the gold standard for reducing overdose risk and supporting recovery.

Where to Get Help

If you or someone you know is experiencing an overdose, call 911 immediately.

SAMHSA National Helpline: 1-800-662-HELP (4357)
Free, confidential, 24/7 treatment referral and information service

Crisis Text Line: Text HOME to 741741
Free, confidential crisis counseling

988 Suicide & Crisis Lifeline: Call or text 988
For mental health crises and emotional support

FindTreatment.gov:
Searchable database of treatment providers

The Bottom Line

Cychlorphine represents the latest evolution in the ongoing synthetic opioid crisis. As drug suppliers continue to introduce new and more potent compounds, the risk of accidental overdose remains high. For families, the best protection is education, preparation, and connection to evidence-based treatment.

The emergence of cychlorphine underscores why harm reduction strategies—naloxone access, drug checking, supervised consumption services where available, and medication-assisted treatment—remain essential public health priorities. These tools save lives while we work toward broader solutions to addiction and the toxic drug supply.

This alert is based on publicly available information from the Center for Forensic Science Research and Education (CFSRE) and peer-reviewed research published in the Journal of Pain Research. If you have questions about substance use or treatment options, contact the SAMHSA National Helpline at 1-800-662-HELP.