DXM, CYP2D6-inhibiting antidepressants, piracetam, and glutamine: proposing a ketamine-class antidepressant regimen with existing drugs.
Frontiers in psychiatry January 1, 2026 Peer reviewed DOI: 10.3389/fpsyt.2026.1751605 via PubMed
Summary
A new four-component treatment regimen is proposed to mimic the rapid antidepressant effects of ketamine by shifting glutamatergic circuits from NMDA-dominant to AMPA-dominant states. The regimen includes dextromethorphan for NMDA antagonism, a CYP2D6 inhibitor to prolong its effects, piracetam as an AMPA modulator, and micronized L-glutamine to support glutamate levels. While preclinical evidence suggests potential synergy, this combination has not yet been tested in humans.
Study at a glance
| Key finding | The proposed treatment regimen could potentially replicate ketamine's effects on mood through a combination of four components, though it remains untested in humans. |
|---|
Abstract
Rapid-acting antidepressants show that mood can lift within hours when glutamatergic circuits shift from an "NMDA-dominant" to an "AMPA-dominant" state. Intravenous ketamine achieves this flip but is hampered by dissociation and logistics, while dextromethorphan + bupropion (Auvelity®) primarily supplies the initial NMDA blockade and yields slower, less durable benefit. We hypothesize that a fully oral, low-cost, four-component regimen may be able to approximate ketamine's full plasticity cascade (1) dextromethorphan (DXM) for NMDA antagonism; (2) a potent CYP2D6 inhibitor (fluoxetine, paroxetine, or high-dose duloxetine) to prolong DXM exposure; (3) piracetam as an AMPA positive allosteric modulator; and (4) micronized L-glutamine to restore presynaptic glutamate pools and buffer against excitotoxicity. Preclinical evidence supports mechanistic synergy along the same axis, but the full combination remains untested in humans. This hypothesis warrants formal preclinical and clinical evaluation.