Pharmacodynamics<unk>  has approximately 50x the potency of the S-(+)-enantiomer as well as greater μ-opioid receptor selectivity. Accordingly, it is about twice as potent as methadone by weight and its effects are virtually identical in comparison. In addition to its activity at the opioid receptors,<unk>  has been found to act as a weak competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor complex and as a potent noncompetitive antagonist of the α3β4 nicotinic acetylcholine (nACh) receptor.
Levomethadone
Isomethadone
Methadone
Normethadone
Morphine
Buprenorphine
Levacetylmethadol
Dezocine