A Staged Translational Framework for Evaluating Oral Glutamatergic and Senescence-Modulating Strategies in...

Treatment-resistant depression (TRD) is commonly operationalized as non-remission after at least two adequately delivered antidepressant trials, but the biological heterogeneity of this population remains substantial. This article presents a translational hypothesis and drug-development framework; it reports no original clinical or laboratory data and is not a systematic review. The central hypothesis is that an oral dextromethorphan-CYP2D6-inhibitor-piracetam regimen could, if pharmacokinetically and clinically validated, initiate glutamatergic plasticity, whereas nicotinamide mononucleotide (NMN) plus N-acetylcysteine (NAC), followed only at a later stage by a candidate senescence-directed agent, could be evaluated for effects on the redox, bioenergetic, inflammatory, and cellular-aging context associated with response durability in a biomarker-enriched subset of unipolar TRD. The core regimen is defined as dextromethorphan, one prespecified CYP2D6 inhibitor, and piracetam. Glutamine is retained only as an optional exploratory component and is not part of the core or augmentation definition used for future testing. Existing evidence is uneven. Human studies establish that CYP2D6 phenotype and inhibition materially alter dextromethorphan exposure; NAC has heterogeneous adjunctive psychiatric evidence; NMN has human NAD-related target-engagement data without established antidepressant efficacy; and senolytics have limited early human data outside TRD. Dasatinib plus quercetin is therefore positioned as a later-stage, specialist-supervised research probe rather than a routine psychiatric augmentation. No clinical role can yet be assigned to any proposed combination, and none should be used outside formal research protocols. The proposed development sequence prioritizes pharmacokinetic characterization, safety, target engagement, biomarker-defined subgroup selection, controlled efficacy testing, and independent replication.