Carfentanil Stats & Data
YDSDEBIZUNNPOB-UHFFFAOYSA-NPharmacology
DrugBankEffect Profile
CuratedModerate sedation and itching/nausea with mild pain relief
Tolerance & Pharmacokinetics
drugs.wikiCross-Tolerances
Harm Reduction
drugs.wikiCarfentanil is one of the most potent opioids identified in drug markets, with estimated quantitative potency around 10,000× morphine and ~100× fentanyl; human activity may begin at ~1 µg, but any specific human lethal dose remains unknown and likely varies widely with tolerance, route, and co‑ingestants. Treat any exposure as a medical emergency. Carfentanil has been detected as an adulterant or substitute for other opioids (e.g., heroin) and can appear in mixed drug supplies; users are often unaware of exposure. Overdose is characterized by rapid and profound respiratory depression, bradycardia, and loss of consciousness; naloxone can reverse opioid toxicity, but compared with heroin, fentanyl‑class overdoses may require faster administration, more rapid escalation, and overall higher or repeated doses of naloxone, with prolonged observation due to recurrent depression. Drug checking resources report that fentanyl test strips (FTS) can detect many fentanyl analogs, including carfentanil, but false negatives/positives are possible; pairing with confirmatory testing and careful sampling across a solution increases detection chances. Do not rely on a single negative result to assume safety. Polysubstance use—especially with benzodiazepines, alcohol, barbiturates, or gabapentinoids—markedly increases the risk of fatal respiratory depression and complicates reversal (naloxone does not reverse non‑opioid sedatives). Because of carfentanil’s potency and risk of recurrent toxicity, bystanders should call emergency services immediately, administer naloxone promptly (repeat if no response in 2–3 minutes), and provide rescue breathing until professionals take over. Expect need for multiple naloxone doses in some cases. Carfentanil presence in local markets is highly variable; relying on lab‑based drug checking programs (e.g., GC/MS) provides more definitive identification than immunoassay strips alone.
References
Drugs.wiki References
- EUDA/EMCDDA–Europol Joint Report on Carfentanil (2017)
- EUDA Best Practice Evidence Summary: Naloxone to revert synthetic opioids overdose
- DrugBank: Carfentanil (search results summary)
- DrugBank: Carfentanil (additional search hits)
- EUDA European Drug Report 2025 – Heroin and other opioids: polysubstance risk
- Toronto Drug Checking Service – Fentanyl test strips resource
- Erowid/DrugsData – lab drug checking project overview