dextromethorphan + bupropion (CSPC Ouyi Pharmaceutical)

dextromethorphan + bupropion is a fixed-dose combination therapy being developed by CSPC Ouyi Pharmaceutical for the treatment of Major Depressive Disorder (MDD). The formulation consists of dextromethorphan, an NMDA receptor antagonist and sigma-1 receptor agonist, and bupropion, which acts as a norepinephrine-dopamine reuptake inhibitor (NDRI) and a potent inhibitor of the CYP2D6 enzyme. By inhibiting CYP2D6, bupropion significantly increases the plasma concentration and half-life of dextromethorphan, which would otherwise be rapidly metabolized. This combination targets the glutamatergic system, providing a rapid-acting alternative to traditional monoaminergic antidepressants. It is currently undergoing Phase 3 clinical trials in China to evaluate its efficacy and safety in adult patients with MDD.