N-Isopropyl butylone is an unscheduled, novel synthetic cathinone analogue bearing structural resemblance to multiple beta-keto methylenedioxyamphetamines (“-ylones”), including N-ethyl pentylone, N,N-dimethylpentylone, and N-propyl butylone. N,N-Dimethylpentylone was placed under control by the World Health Organization in December 2024 and by the U.S. Drug Enforcement Administration in August 2025. As a result, its positivity has decreased over the last year as that of N-isopropyl butylone has increased as a replacement in the illicit drug market.
N-Isopropyl butylone was first identified by our laboratory in August 2024 in a drug material submitted from Georgia. Since then, N-Isopropyl butylone has been detected in more than 40 forensic samples, including 21 toxicological specimens from fatal and non-fatal overdoses, primarily from Florida. More than half of the cases were polydrug intoxications, testing positive for other drugs such as cocaine, methamphetamine, and fentanyl. Additional NPS detected included N,N-dimethylpentylone, alpha-PiHpP (also known as iso-PV8), bromazolam, and 2F-2oxo-PCE. Our laboratory received 18 postmortem and 3 antemortem specimens. Age ranged from approximately 25 to 60 years, when provided. The toxicity of N-isopropyl butylone has not been formally examined but recent associations with intoxication and death lead professionals to believe that this drug has the potential to cause harm and is of high public health concern, when mixed with other drugs or when consumed alone at high doses.
