Dimemorfan
Dimemorfan (INN) (or dimemorphan) (brand names Astomin, Dastosirr, Tusben), or dimemorfan phosphate (JAN), also known as 3,17-dimethylmorphinan, is an antitussive (cough suppressant) of the morphinan family that is widely used in Japan and is also marketed in Spain and Italy. It was developed by Yamanouchi Pharmaceutical (now Astellas Pharma) and introduced in Japan in 1975. Dimemorfan is an analogue of dextromethorphan (DXM) and its active metabolite dextrorphan (DXO), and similarly to them, acts as a potent agonist of the σ1 receptor (Ki = 151 nM). However, unlike DXM and DXO, it does not act significantly as an NMDA receptor antagonist, and for this reason, lacks dissociative effects, thereby having reduced side effects and abuse potential in comparison. Similarly to DXM and DXO, dimemorfan has only relatively low affinity for the σ1 receptor (Ki = 4421 nM).