CNS-5161 is an NMDA receptor antagonist which was under development for the treatment of neuropathic pain and cancer pain but was never marketed. It is taken by intravenously or transdermally.
The drug is a highly potent and selective noncompetitive antagonist of the NMDA receptor via the ion channel or dizocilpine (MK-801) binding site, with an affinity (K<sub>i</sub>) of 1.8nM. It produces analgesic, anticonvulsant, and neuroprotective effects in rodents. There was also some dose-dependent mortality related to respiratory failure in rodents.
In humans, the drug was found to produce mild dissociative-like effects such as visual disturbances and derealization at assessed doses of 250 to 2,000üg intravenously in clinical trials. In addition, it produced pronounced and dose-limiting hypertension.
The chemical synthesis of CNS-5161 and isotopologues has been described.
CNS-5161 was under development by CeNeS Pharmaceuticals. It reached phase 2 trials prior to the discontinuation of its development.