Ketamine and nitrous oxide: The evolution of NMDA receptor antagonists as antidepressant agents.
Journal of the neurological sciences May 15, 2020 Molly C Kalmoe, Alvin M Janski, Charles F Zorumski et al.
NMDAR antagonists like ketamine and nitrous oxide are being studied as rapid-acting antidepressants. Intravenous ketamine rapidly reduces depressive and suicidal symptoms in treatment-resistant depression (TRD), as shown by several trials. The FDA has approved intranasal esketamine for TRD, with a REMS program to minimize misuse. Nitrous oxide, a gas used for anesthesia and analgesia, also acts as an NMDAR inhibitor. A recent double-blind, prospective, cross-over study found that nitrous oxide reduced depressive symptoms in severely ill TRD patients, though further research is needed.