After years of off-label use, the United States FDA approved the first ketamine related drug back in 2019. Though it’s a very unique intranasal preparation of S-Ketamine called Spravato.
Before this, everyone received intravenous forms of Ketamine infusion containing both S-Ketamine and R-Ketamine
When someone uses ketamine, they’re exposed to two isomers, specifically the S & R enantiomers of Ketamine. This are effectively two different drugs with different properties.
S-Ketamine vs R-Ketamine
S-Ketamine has a higher affinity for NMDA Receptors and is more potent as an anesthetic and analgesic. Therefore the NMDA receptors and S-Ketamine receive much more attention for those reasons.