What is "alphacetylmethadol"

n. A synthetic opioid analgesic.

Alphacetylmethadol ( INN), or α-acetylmethadol (AAM), is a synthetic opioid analgesic. Its levorotary enantiomer, levacetylmethadol, is an FDA-approved treatment for opioid addiction. Alphacetylmethadol is very similar in structure to methadone, a widely prescribed treatment for opioid addiction. In the United States, it is a Schedule I controlled substance under the Controlled Substances Act (presumably because it was never marketed in the US, as is the case with other common opiate/opioid medications such as diacetylmorphine and alphaprodine), with an ACSCN of 9603 and a 2013 annual manufacturing quota of 2 grammes.