Tetramethylfentanyl

The following information was compiled in October 2025 and is subject to change as new research is conducted and as new information becomes available:

Description: Tetramethylfentanyl is a synthetic opioid structurally similar to fentanyl and fentanyl analogues. Tetramethylfentanyl has been reported in trace amounts in drug materials containing BTMPS and it is assumed fentanyl-related precursors, byproducts, and intermediates (e.g., tetramethylfentanyl) could be manufactured from BTMPS.¹ Tetramethylfentanyl was first identified by our laboratory in March 2025.

Sample Source: U.S. Customs and Border Protection (CBP)

Sample Appearance: White solid material

Pharmacology: No information is available on the activity and potency of tetramethylfentanyl; however, prior data for fentanyl analogues suggests this drug would be lower in potency.

Toxicology: Tetramethylfentanyl has not been detected in toxicology cases to date at the CFSRE.

Drug Materials: Tetramethylfentanyl has been detected in two drug materials to date at the CFSRE.

Demographics / Geographics: The drug materials originated from the U.S.-Mexico Southwest Border. Tetramethylfentanyl was identified alongside synthetic opioids (e.g., fentanyl, carfentanil) and adulterants (e.g., BTMPS, lidocaine).

Legal Status: Tetramethylfentanyl is a Schedule I drug in the United States (21 CFR 1308).

Class:

Opioid

Appearance:

White solid material

Formula:

C26H36N2O

MW:

392.6

[M+]:

392

[M+H]+:

393.2900

IUPAC:

N-phenyl-N-[2,2,6,6-tetramethyl-1-(2-phenylethyl)-4-piperidyl]propanamide

Report Date:

October 21, 2025