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***All questions or comments regarding this alert should be directed or sent to LDH Dept of Public Health.***

Cychlorphine: Emerging, Highly-Potent Synthetic Opioid

The Louisiana Department of Health (LDH) is alerting healthcare and laboratory providers to the detection of 

cychlorphine (N-propionitrile chlorphine)

, an emerging synthetic opioid identified in Louisiana and other states.

Cychlorphine is an emerging synthetic opioid identified in the illicit drug supply across the United States, including in counterfeit pills and drug mixtures. Because routine toxicology testing may not detect cychlorphine, clinicians should 

not use a negative routine opioid or fentanyl screen to exclude opioid poisoning

The priority remains rapid recognition and treatment of opioid toxicity, including 

support of ventilation and administration of naloxone

 when clinically indicated, even when routine drug screening is negative. Because cychlorphine can be more potent than fentanyl, 

overdoses may require multiple doses of naloxone

Office of National Drug Control Policy (ONDCP)

 at the White House reported 106 drug-supply reports across 10 states in 2025, with detections in all four U.S. Census regions. Cychlorphine has been linked to at least 55 deaths nationally from 2025 to 2026, with the highest prevalence in Ohio, Texas, and Tennessee. These data are evolving as surveillance and toxicology testing expand.

There has been evidence of exposure to cychlorphine in Louisiana, and at least two opioid-related deaths involved cychlorphine since December 2025.

Key Clinical Messages in Managing Suspected Opioid Overdose

1. Suspect opioid poisoning based on the clinical presentation, not the toxicology screen.

Patients with depressed consciousness, respiratory depression, or hypoventilation 

should be treated for suspected opioid poisoning when clinically appropriate

, even when routine drug testing is negative.

Routine fentanyl screens may also be negative.

Standard fentanyl and nitazene test strips do not reliably identify cychlorphine.

A positive fentanyl or other opioid result does not exclude co-exposure to cychlorphine.

·A negative screen does not rule out cychlorphine or another opioid exposure. 

Identification generally requires an expanded laboratory method, such as mass spectrometry, that specifically includes cychlorphine.

2. Support ventilation AND administer naloxone.

For a patient with suspected opioid toxicity:

Immediately assess and support airway and breathing.

Provide assisted ventilation, oxygen, and other airway support as clinically indicated.

Administer naloxone when opioid toxicity is suspected.

, rather than requiring complete reversal of sedation.

·Reassess frequently for recurrent respiratory depression.

3. Be alert for recurrent or persistent toxicity.

Patients with suspected cychlorphine or other synthetic opioid exposure may require 

Repeated naloxone dosing or a naloxone infusion may be appropriate when clinically indicated.

 including other central nervous system depressants like benzodiazepines.

Repeatedly escalating naloxone is not a substitute for adequate airway and ventilatory support.

·Disposition should be based on the patient's clinical course and response to treatment rather than an assumed duration of cychlorphine effect.

Routine testing may not detect cychlorphine.

1.  Determine whether cychlorphine/N-propionitrile chlorphine is included in their current testing panels.

Identify whether testing is performed in-house or through a reference laboratory.

Determine whether previously collected or retained specimens can be evaluated using an expanded toxicology panel.

4. Establish a clear specimen-referral pathway for suspected cases.

Preserve appropriate residual specimens from unusual cases.

When clinically and operationally appropriate, clinicians and laboratories should 

preserve residual specimens from unusual or unexplained suspected opioid poisonings

 under laboratory guidance so that additional testing can be considered.

A clinical opioid toxidrome but a negative routine opioid/fentanyl screen;

Unexpected or unusually severe respiratory depression;

Recurrent respiratory depression after initial treatment;

Suspected exposure to counterfeit pills or an unknown drug;

An unusual cluster of suspected opioid poisonings; or

·A toxicology result that does not adequately explain the patient's clinical presentation.

Do not delay clinical treatment while arranging additional testing.

Specimen collection, storage, handling, and referral should follow the submitting laboratory's requirements and applicable clinical, legal, and institutional policies.

Louisiana’s opioid-related surveillance relies on accurate data from clinicians. The 

Louisiana Opioid Data and Surveillance System (LODSS)

 is an interactive, public-facing online dashboard utilizing aggregate critical health data including opioid-related deaths, emergency department overdose visits, inpatient hospitals admissions, and localized opioid prescription rates. Please ensure you're appropriately coding data submitted in the EHR using specific ICD-10 codes so that we have the most detailed data possible.

Coding for cychlorphine is not currently possible because there are no cychlorphine-specific ICD-10 codes. Depending on the diagnosis code documented in the medical record, LDH may capture these cases as opioid overdoses. However, the more specific and accurate the diagnosis coding, the better we can identify and categorize these cases.

https://www.dea.gov/press-releases/2026/05/12/public-safety-advisory

https://ndews.org/wordpress/files/2026/05/ONDCP-Drug-Threat-Notice-Cychlorohine_Final.pdf

·Novel Opioid Cychlorphine Linked to Non-Fatal Overdose in First Direct Evidence of Patient Exposure: 

https://www.acmt.net/news/novel-opioid-cychlorphine-linked-to-non-fatal-overdose-in-first-direct-evidence-of-patient-exposure/

·Novel Synthetic Opioid Cychlorphine: What Doctors Should Know: 

https://www.medpagetoday.com/publichealthpolicy/opioids/122919

https://www.cdc.gov/overdose-prevention/prevention/index.html

·Increase in Fatal Overdoses Linked to Novel Synthetic Opioid N-Propionitrile Chlorphine (Cychlorphine): 

https://www.cfsre.org/nps-discovery/public-alerts/increase-in-fatal-overdoses-linked-to-novel-synthetic-opioid-n-propionitrile-chlorphine-cychlorphine

***All questions or comments should be directed or sent to LDH Dept of Public Health.***