BTMPS is the Latest Illicit Drug Adulterant

In recent years, novel adulterants, such as xylazine and medetomidine, have adulterated fentanyl and other illicit drugs. Another adulterant BTMPS (2,2,6,6-tetramethyl-4-piperidyl) sebacate) was first detected in June 2024 in Portland, OR, and Philadelphia, PA. Within weeks, forensic labs across the country began to detect it in fentanyl samples. 

BTMPS is a hindered amine light stabilizer that is used as a UV protectant in plastics and adhesives. Unlike other adulterants, it has no known sedative or psychoactive effects. Illicit drug manufacturers may be using it as an inexpensive bulking agent to dilute fentanyl and maximize profits. Another possibility, is that manufacturers add BTMPS to stabilize fentanyl and extend its shelf life.

The toxicological effects of BTMPS in humans is unknown. Anecdotal reports have mentioned symptoms such as blurred vision, conjunctivitis, tinnitus, nausea, and a strong chemical taste or odor. Drug injection is associated with skin irritation, while smoking can cause persistent cough, throat irritation, and hemoptysis.

Animal studies have shown that BTMPS is a potent antagonist of L-type calcium channels and nicotinic acetylcholine receptors. Blockage of these channels could cause cardiotoxic effects such as hypotension and decreased myocardial contractility. It could also cause neurotoxicity such as autonomic dysfunction, muscle weakness, and ptosis.

Reference

Zhu DT et al. The Rapid Spread of a Novel Adulterant in the US Illicit Drug Supply-BTMPS, JAMA Intern Med, July 7, 2025, doi:10.1001/jamainternmed.2025.3037