Wiki/N-Phenethyl-Noroxymorphone

N-Phenethyl-Noroxymorphone, also known by its acronym PHM, is an extremely potent opioid of the morphinan class. Chemically it can be described as similar to opioid receptor antagonists such as Naloxone or Naltrexone, however, despite the chemical reassemblence, strongly activates the µ-Opioid receptors. It has been encountered in research chemical shops in Germany and is as of May 2026 not federally scheduled there. PHM displays the same behavior as other opioid agonists, in that it leads to β-Arrestin 2 recruitment, so dependency and withdrawal if use of this substance is discontinued should be comparable to other more classical opioids such as fentanyl or morphine. The molecule is highly lipophilic due to the addition of a phenylethyl group, therefore it can penetrate the synaptic cleft stronger than a traditional opiate would. This effect is also visible with one of its sister compounds it is very closely related to, N-Phenethyl-Normorphine. The compound, while being new to the research chemical market, has first been synthesized in the 1960s as a potent analgesic, but was never marketed. Like many other drugs, its appearance can be described as a white powder without any notable odors or discolorations mentioned.

Pharmacology

PHM is highly selective for the mu-opioid receptor over the kappa-opioid receptor and presents roughly 2x the affinity and potency at the mu-opioid receptors that oxymorphone exhibits.