Tox In Focus | NPS Benzodiazepines

Tox In Focus

Focused Clinical Reference

Vol. 14 · NPS Benzodiazepines · July 2026

Drug Quick Reference

Drug Class / Mechanism

Novel psychoactive 'designer' benzodiazepines

GABA-A agonists; potency and duration vary

Street Names

'Fake Xanax', 'Dope' (bromazolam)

'Clam' (clonazolam); 'Liquid Xanax' (flubromazolam)

Routes of Administration

Tablets (counterfeit Xanax/Klonopin)

Powder, liquid, blotter paper

Commonly Detected With

Fentanyl ('benzo-dope') · Other benzodiazepines, opioids

Metabolism

Phase I CYP + phase II UGT (UGT1A4)

Several agents poorly characterized

Window of Detection

Etizolam ~1 to 2 days; flubromazolam ~2 to 5 days

Bromazolam/clonazolam/flualprazolam: not established

Control Status

Not FDA-approved; many DEA Schedule I

Etizolam prescribed abroad, not in the US

NPS BENZODIAZEPINES

Designer benzodiazepines and 'benzo-dope' outside the standard benzo screen

Designer (NPS) benzodiazepines are illicit GABA-A agonists sold as 'research chemicals' or as counterfeit Xanax and Klonopin. They vary widely in potency and duration, are frequently combined with fentanyl ('benzo-dope'), and are not reliably detected by standard benzodiazepine immunoassays.¹

Why This Matters Now

Bromazolam and other designer benzodiazepines have surged across the US, largely alongside fentanyl, and appear in fatal and impaired-driving cases.² Some, such as flubromazolam, cause prolonged severe intoxication with coma, hypotension, and rhabdomyolysis.³

⚠ A negative benzodiazepine screen does not exclude a designer benzodiazepine. When sedation is severe or 'benzo-dope' is suspected, request targeted NPS-benzodiazepine LC-MS/MS.

Clinical Presentation

INTOXICATION

Strong sedation, drowsiness

Amnesia, slurred speech

Loss of coordination

Respiratory depression

Flubromazolam: coma, hypotension, rhabdomyolysis

WITHDRAWAL

Benzodiazepine-type withdrawal

Anxiety, insomnia, agitation

Tremor

Autonomic instability

Seizure risk

Important: Designer benzodiazepines vary enormously in potency, and flumazenil use is complex and can precipitate seizures. Combined with fentanyl ('benzo-dope'), they add sedation that naloxone does not reverse.

UDT Considerations

Standard benzodiazepine immunoassays do not reliably detect designer benzodiazepines. Targeted LC-MS/MS identifies specific agents and metabolites (e.g., bromazolam, 8-aminoclonazolam, etizolam and alpha-hydroxyetizolam, flualprazolam, flubromazolam).¹ Because the class evolves quickly, confirm the current analyte menu with the laboratory.

Clinical Guidance

Do not rely on benzodiazepine immunoassays to detect designer benzodiazepines; order targeted LC-MS/MS.
Suspect a designer benzodiazepine with severe or prolonged sedation and a negative or low benzodiazepine screen.³
Recognize 'benzo-dope' (designer benzodiazepine plus fentanyl); the benzodiazepine component is not reversed by naloxone.
Confirm the laboratory's current NPS-benzodiazepine menu, since analogues change frequently.
Interpret detection windows cautiously; data are limited for bromazolam, clonazolam, and flualprazolam.

Point-of-Care Testing Availability

Available strips

No point-of-care strip reliably detects designer benzodiazepines.

Clinical use

Standard benzodiazepine immunoassays detect these agents inconsistently, if at all.

Limitations

Identification requires targeted LC-MS/MS for specific analytes.

NPS BENZODIAZEPINES | Clinical & Program Guidance

Tox In Focus Vol. 14 · July 2026 · Page 2 of 2

Interpreting the Test Result

▲ If Testing Is Positive

Confirms a specific designer agent. Detection indicates use within the window of detection for that analyte.

Separate from the standard panel. A designer-benzodiazepine positive is a different test from the prescription benzodiazepine panel.

Timing is uncertain. Windows are established only for etizolam (~1 to 2 days) and flubromazolam (~2 to 5 days).¹

▼ If Testing Is Negative or Not Done

Does not exclude the class. A novel designer benzodiazepine may not be on the panel.

Not reliably on benzo screens. Standard benzodiazepine immunoassays can miss these agents.

Timing and cutoff. Absence may reflect timing of last use, dose, or levels below the cutoff.

Metabolism & Urinary Markers

Designer benzodiazepines and metabolites measured on the definitive panel.

Metabolite	Clinical Significance
Bromazolam	High-prevalence designer benzodiazepine, often with fentanyl; window not established.
Clonazolam (8-aminoclonazolam)	Potent triazolo-benzodiazepine; measured as its metabolite.
Etizolam / alpha-hydroxyetizolam	Thienodiazepine prescribed abroad; about 1 to 2 day window.
Flualprazolam; flubromazolam	Potent agents; flubromazolam about 2 to 5 day window, severe toxicity reported.

Key References

Brunetti P, et al. Designer benzodiazepines: a review of toxicology and public health risks. Pharmaceuticals (Basel). 2021;14(6):560.
Center for Forensic Science Research and Education. Bromazolam prevalence surging across the United States. 2022.
Bohnenberger K, Liu MT. Flubromazolam overdose: a review of a new designer benzodiazepine and the role of flumazenil. Ment Health Clin. 2019;9(3):133-137.

DISCLAIMER: This document is intended for clinical reference and educational purposes only. It does not constitute medical, legal, or professional advice and should not replace independent clinical or programmatic judgment. Content reflects published data available at time of preparation. ToxiPharm LLC makes no warranties regarding completeness or applicability in all settings. | © 2026 ToxiPharm LLC | toxipharm.org