spravato_annual_worldwide_sales_2019_2026More than six decades after Calvin Stevens first synthesized ketamine at Parke-Davis while searching for a safer anesthetic, the molecule has completed its migration into psychiatry, where it has become a blockbuster. Esketamine, the more potent S-enantiomer of that original compound, won FDA approval for treatment-resistant depression as a nasal spray in March 2019, then…