NeuroRx believes

that its therapeutic approach may offer an oral, outpatient treatment with the potential to significantly extend ketamine’s anti-suicidal and antidepressant benefits.

All information on this page refers to a mechanism of action of an investigational drug – not approved by the FDA

© 2016 NeuroRx, Inc.

*This drug is investigational and not approved by the US FDA


Mechanism of Action

NRX-101 (Cyclurad™)'s proprietary mechanism of action targets the NMDA and 5-HT2a receptors - two key receptors in the brain.


The NMDA receptor is a glutamate receptor found in nerve cells.  It is critical to the memory function as it controls signaling from neuron to neuron.  NMDA also directly regulates a calcium ion channel that controls the rate of ideation (formation of new ideas) in the brain. D-cycloserine, one of the active ingredients in NRX-101, targets the NMDA receptor and modulates NMDA activity, potentially fostering a normal pace of thought generation. Multiple human studies have demonstrated that administration of D-cycloserine triggers an antidepressant effect. However, the treatment requires administration with an antipsychotic to counteract side effects.


The 5-HT2a receptor is a G protein-coupled receptor and a member of the serotonin family. It is known for its role in mediating certain antipsychotic drugs. Lurasidone, the other active ingredient in NRX-101, is a 5-HT2a antagonist that is currently approved as an antipsychotic, and for use in bipolar depression. Laboratory studies have shown that Lurasidone and other 5-HT2a antagonists have an unexpected synergistic effect with D-cycloserine, potentially enhancing the antidepressant effect while minimizing the potential psychomimetic (hallucinations) side effects. A phase 2 human study has shown results consistent with this finding.


NRX-101's proprietary combination of D-cycloserine and Lurasidone is designed to be administered daily for approximately six weeks following an initial, single infusion of ketamine. The company believes that this therapeutic approach may offer an oral, outpatient treatment with the potential to significantly extend Ketamine’s anti-suicidal benefit and offer an improved side effect profile.






NMDA regulates the speed of thoughts:

Too little NMDA activity > Increased Ideation, hallucinations, psychosis

Too much NMDA activity > Reduced Ideation, depression, suicide