Esketamine is an S(+)-enantiomer of ketamine. It is a nonselective, noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptor. A nasal spray, containing esketamine, was approved in 2019 for the treatment of treatment-resistant depression in adults, in conjunction with an oral antidepressant, and is marketed under tradename SPARAVATO. Esketamine is a schedule III drug product in the USA.

ADX-71149 (JNJ-40411813), a phenylpiperidine-substituted pyridone, is positive allosteric modulator (PAM) metabotropic glutamate type 2 (mGlu2) receptor activity. In fed rats, JNJ-40411813 was rapidly absorbed with an absolute oral bioavailability of 31%. ADX-71149 (JNJ-40411813) demonstrates antipsychotic activity in vivo rodents experiments. ADX-71149 (JNJ-40411813) is being jointly developed by Addex Therapeutics and Janssen Pharmaceuticals, a Johnson & Johnson company, for the treatment of epilepsy. Addex Therapeutics was also developing the candidate for schizophrenia, major depressive disorder and anxiety disorders. However, development in these indications has been discontinued.