Cychlorphine (N-Propionitrile Chlorphine): Complete Toxicology, Overdose & Safety Monograph

Cychlorphine (N-Propionitrile Chlorphine): Complete Toxicology, Overdose & Safety Monograph

Emergency opioid warning: Cychlorphine is a potent synthetic opioid. If someone cannot be awakened, has slow/irregular/stopped breathing, blue or gray lips/skin, gurgling/choking, or collapses after an unknown pill or powder, call emergency services and give naloxone if available. Do not wait for a drug test or exact identification.

Quick answer

Cychlorphine is a rapidly emerging synthetic opioid in the “orphine” or piperidine benzimidazolone family. Its chemical name is N-propionitrile chlorphine, and it is structurally distinct from both fentanyl analogues and nitazenes.

It moved from first U.S./forensic detections in 2024 to a substantial fatal-overdose signal by 2025–2026.

The strongest current evidence includes:

• analytically confirmed human nonfatal overdose with respiratory depression and naloxone treatment;
• CFSRE detection in 25 fatal-overdose blood specimens by January 2026;
• UNODC reporting from 10 countries, 182 drug seizures, and 78 fatal-overdose detections by May 2026;
• DEA reporting 49 DEA TOX fatalities with N-propionitrile chlorphine identified by the time of the August 2026 scheduling order;
• potent preclinical MOR activity and animal respiratory/cardiovascular depression.

These numbers come from different surveillance systems and time windows and may overlap. They must not be added together to manufacture a cumulative death count.

Identity

What are orphines?

Orphines are a newer illicit-market label for a family of opioids related to piperidine benzimidazolone chemistry.

Members include:

• brorphine;
• chlorphine;
• cychlorphine;
• spirochlorphine;
• spirobrorphine;
• 5,6-dichloro desmethylchlorphine;
• 5,6-dichloro brorphine.

They are not nitazenes. Nitazenes are 2-benzylbenzimidazole opioids with a different core structure.

The overlap is pharmacological: both families can produce powerful mu-opioid receptor effects and fatal respiratory depression.

History

The orphine lineage connects to pharmaceutical opioid-discovery work dating back to the 1960s and 1970s.

Brorphine emerged in modern recreational drug markets around 2019–2020.

Cychlorphine appeared later:

• DEA reported a first laboratory detection in the United States in 2024;
• CFSRE first detected it in mid-2024 and confirmed it with reference material;
• fatal-overdose positivity increased markedly from mid-2025 into early 2026;
• international spread was evident by 2026.

The timing overlapped with broader controls on nitazene core structures and declining nitazene positivity in some forensic datasets. CFSRE and UNODC describe an orphine rise alongside nitazene decline.

That is an important market observation, not proof of a simple one-law/one-drug causal substitution.

Pharmacology

Mu-opioid receptor activity

Cychlorphine is a potent opioid agonist.

UNODC summarizes recent pharmacology as showing:

• strong mu-opioid receptor activity;
• additional activity at kappa and delta opioid receptors;
• potency exceeding fentanyl in some experimental systems;
• profound respiratory and cardiovascular depression in mouse models at lower doses than fentanyl.

“10 times fentanyl” needs context

A commonly repeated claim says cychlorphine is approximately 10× more potent than fentanyl.

That shorthand comes from preclinical/in-vitro evidence and should not be used as a human dose conversion.

It does not mean:

• a fixed 10:1 human dose ratio;
• a predictable overdose threshold;
• a validated morphine-milligram equivalent;
• a safe amount below some calculated value.

Potency depends on assay and endpoint.

Human overdose evidence

Biologically confirmed case

A 2026 Journal of Medical Toxicology report described a woman in her 20s who believed she had ingested alprazolam.

She developed:

• unresponsiveness;
• respiratory depression.

Emergency medical services administered 6 mg intranasal naloxone before hospital arrival.

Comprehensive serum toxicology confirmed cychlorphine along with bromazolam and several other substances.

This case is important for two reasons:

1. it provides direct human evidence of a clinically significant opioid toxidrome with cychlorphine present;
2. the reported product identity did not match the opioid detected, demonstrating counterfeit/mislabeled exposure risk.

Because bromazolam and other drugs were also present, the case should not be presented as a clean single-drug pharmacology experiment.

Additional nonfatal case

A separate Clinical Toxicology report describes a nonfatal opioid overdose associated predominantly with cychlorphine.

Together these reports move cychlorphine beyond purely forensic inference.

Fatal-overdose surveillance

CFSRE

In January 2026, CFSRE reported cychlorphine in 25 blood specimens from fatal overdoses.

• specimens came from eight U.S. states and three Canadian provinces;
• cychlorphine was the sole opioid in 11 of the 25 cases;
• co-detection with fentanyl, oxycodone, stimulants, novel benzodiazepines and other NPS also occurred.

UNODC

By May 2026, UNODC reported cychlorphine in:

• 10 countries;
• 182 drug seizures;
• 78 fatal overdoses.

DEA TOX

DEA's August 2026 temporary scheduling record reported 49 fatalities in which DEA TOX had positively identified N-propionitrile chlorphine.

In five, DEA stated the compound was present at low levels either alone or with other substances at negligible concentrations.

Why the counts cannot simply be added

CFSRE, NMS Labs, DEA TOX, national laboratories and UNODC can receive overlapping cases.

Without case-level deduplication, “25 + 78 + 49” is not a valid cumulative total.

This site reports each dataset with its source and time window instead.

Acute toxicity

Expected and documented opioid-type effects include:

• profound sedation;
• miosis;
• slowed breathing;
• hypoxia;
• unresponsiveness;
• bradycardia;
• hypotension/cardiovascular depression;
• cardiac arrest;
• death.

Unknown-product exposures can also contain benzodiazepines, fentanyl, xylazine, stimulants or other NPS, complicating the presentation.

Naloxone

Naloxone is appropriate when cychlorphine or another opioid is suspected.

The biologically confirmed human case demonstrates naloxone use in a cychlorphine-positive overdose.

No controlled study establishes a special cychlorphine-specific naloxone dose.

Repeat dosing and monitoring may be necessary because:

• exposure quantity is usually unknown;
• potency is high;
• duration is not well characterized in humans;
• other depressants may be present;
• re-sedation can occur.

Emergency care remains necessary after initial response.

Pharmacokinetics and metabolism

This is a major evidence gap.

No controlled human cychlorphine study has established:

• oral/intranasal bioavailability;
• time to peak concentration;
• half-life;
• volume of distribution;
• renal clearance;
• hepatic enzyme pathways;
• accumulation with repeated exposure;
• active human metabolites.

Forensic detection proves exposure; it does not fill in a controlled PK curve.

Anecdotal duration reports should not be promoted into measured pharmacokinetics.

Interactions

No controlled cychlorphine interaction trial exists.

The highest concern is co-exposure to other CNS/respiratory depressants:

• fentanyl and other opioids;
• benzodiazepines;
• alcohol;
• xylazine-containing mixtures;
• gabapentinoids;
• sedative-hypnotics.

Stimulants may add cardiovascular stress without preventing opioid respiratory depression.

Tolerance and physical dependence

Direct prospective cychlorphine tolerance/dependence studies are absent.

However, potent MOR agonism makes:

• tolerance;
• physical dependence;
• loss-of-tolerance overdose risk;
• opioid withdrawal

biologically credible.

The correct evidence language is “strong class-based concern, not quantified cychlorphine incidence.”

Withdrawal

No validated cychlorphine-specific withdrawal timeline exists.

If physical dependence develops, an opioid-like syndrome may include:

• restlessness;
• sweating/chills;
• insomnia;
• GI symptoms;
• muscle aches;
• anxiety;
• autonomic activation;
• craving.

The exact onset, peak and duration are not established.

A counterfeit or changing product supply makes brand-based taper advice especially unreliable.

Dependence vs addiction

Physical dependence means withdrawal follows neuroadaptation.

Opioid use disorder is a broader syndrome that can include:

• craving;
• inability to cut down;
• escalating use;
• repeated hazardous use;
• continuing despite overdose or medical harm;
• interference with responsibilities.

A person can become opioid-dependent through a counterfeit “benzodiazepine” product without initially knowing an opioid is present.

Treatment and support

There is no cychlorphine-specific FDA-approved treatment protocol.

If someone develops opioid withdrawal or OUD after an unknown/cychlorphine-containing product, clinicians can use established opioid-treatment frameworks.

Evidence-based OUD medications include:

• buprenorphine;
• methadone;
• extended-release naltrexone in appropriately selected people after adequate opioid abstinence.

This page does not provide self-induction or taper doses.

U.S. resources:

• FindTreatment.gov
• SAMHSA National Helpline: 1-800-662-HELP (4357)

Testing and toxicology

Fentanyl and nitazene strips

UNODC specifically notes that emerging orphines are not reliably detected by fentanyl or nitazene test strips.

Therefore:

A negative fentanyl or nitazene strip does not establish that an unknown sample is free of a potent synthetic opioid.

Routine clinical screens

Conventional opioid immunoassays may also miss cychlorphine because the compound is new and structurally distinct from the opioids those assays were designed around.

Definitive identification

Confirmation may require:

• targeted LC-MS/MS;
• LC-HRMS/QTOF;
• updated spectral libraries;
• authentic reference standards;
• retrospective data mining when a new reference spectrum becomes available.

This information is about clinical/forensic limitations, not avoiding testing.

Counterfeit and mislabeled products

The analytically confirmed case involving a product reportedly taken as alprazolam highlights a central risk: the person may not knowingly choose an opioid.

Unknown tablets can contain:

• an orphine;
• a designer benzodiazepine;
• both;
• or additional substances.

Appearance and imprint are not chemical analysis.

Forensic interpretation

Detection is not automatically sole causation

A cychlorphine-positive fatality can involve:

• fentanyl;
• other opioids;
• benzodiazepines;
• stimulants;
• other NPS;
• underlying disease.

The fact that cychlorphine was the sole opioid in some CFSRE fatalities strengthens causal concern, but case-by-case interpretation is still required.

No universal fatal blood level

There is no validated personal lethal cychlorphine concentration.

Interpretation depends on:

• specimen type;
• postmortem redistribution;
• timing;
• tolerance;
• co-drugs;
• analytical method;
• metabolites;
• medical/scene findings.

A concentration from a death should never be turned into a dosing target or “safe threshold.”

Epidemiology and market evolution

Cychlorphine's timeline is unusually compressed:

• first U.S./CFSRE detections: 2024;
• rapidly increasing fatal positivity: 2025;
• major North American/international alert signal: early 2026;
• temporary U.S. Schedule I: August 27, 2026.

This is why NPS surveillance often detects major risk before ordinary clinical education catches up.

Legal status

United States

DEA temporarily placed N-propionitrile chlorphine (cychlorphine) in Schedule I effective August 27, 2026 through August 27, 2028, unless the temporary action is extended or replaced by permanent scheduling.

The same order covers:

• 5,6-dichloro brorphine;
• 5,6-dichloro desmethylchlorphine;
• spirochlorphine.

International

UNODC EWA tracks cychlorphine as an emerging NPS/opioid. Country-level legal controls vary.

Do not assume every orphine has identical international legal status.

Special populations

No controlled cychlorphine safety studies exist for:

• pregnancy/breastfeeding;
• adolescents;
• older adults;
• chronic respiratory disease/sleep apnea;
• significant hepatic/renal disease;
• seizure disorders.

High-potency opioid pharmacology plus absent human PK makes these evidence gaps particularly concerning.

Myths and common misconceptions

“Cychlorphine is a nitazene.”
No. It is an orphine/benzimidazolone opioid.

“It is exactly 10 times fentanyl.”
Not in a clinically validated human sense. That shorthand comes from preclinical pharmacology.

“A negative fentanyl strip rules it out.”
False.

“Naloxone will not work because it is a new opioid.”
False. Naloxone is appropriate for suspected opioid toxicity, and human cychlorphine-positive overdose care has included naloxone.

“All reported cychlorphine deaths were cychlorphine-only.”
False. Many involved co-drugs; some cases did have cychlorphine as the sole detected opioid.

“No published withdrawal cohort means dependence is impossible.”
False. Potent MOR agonism creates a strong dependence concern; exact human incidence and timing remain unknown.

Evidence ledger

Related evidence

• Orphine opioids family monograph
• Brorphine
• Nitazene opioids
• Designer synthetic opioids beyond nitazenes
• Research chemicals & NPS evidence map
• Substance Use, Dependence & Harm Reduction hub

Bottom line

Cychlorphine went from an unfamiliar forensic name to an international fatal-overdose signal in roughly two years.

The evidence now supports far more than calling it an “early-warning compound”: there are direct human overdoses, naloxone use, dozens of fatal toxicology detections, international spread, and strong preclinical evidence of dangerous opioid pharmacology.

What remains missing is equally important: controlled human PK, a dependence/withdrawal cohort, long-term safety data and any defensible consumer dose.

The responsible conclusion is therefore high hazard, rapidly growing real-world evidence, and major unresolved clinical uncertainty.