Ketamine IV infusion - Racemic ketamine, which is administered intravenously, goes directly to the patient’s bloodstream. This is called intravenous, or IV, ketamine. The treatment is a mix of two mirror-image molecules, which are called “R” and “S” ketamine. The FDA approved its use decades ago for use as an anesthetic. For patients with treatment-resistant depression, doctors are using it off-label. IV ketamine infusion therapy is not a first-line treatment for depression. Rather, it’s administered when antidepressant medications fail. Administered through an IV infusion in the arm, ketamine takes effect right away, and the effects can last from days to weeks. Patients typically receive a series of six infusions over two to three weeks as part of an “induction” phase. After that, the maintenance period begins, and patients typically return for one infusion every two to six weeks. Doctors have also used ketamine to treat bipolar disorder; however, they do not prescribe it for children or those patients experiencing mania, active psychosis, or unstable cardiovascular disease. Esketamine (Spravato™) nasal spray - Esketamine (Spravato) is administered as a nasal spray. It uses only the “S” molecule rather than the combination of both R and S. This form of ketamine treatment is FDA approved; however, there is far less research on its effectiveness in treating depression. The two forms of ketamine interact differently with brain receptors, and the delivery method (IV versus nasal spray) also affects the drug’s effectiveness as well as side effects. Much more research is needed to compare the efficacy of esketamine (Spravato).